Pharmacology

PRACTICAL PHARMACOLOGY
FOR 2nd YEAR MEDICAL STUDENTS
2020
5MEDX TEAM

Background:
Drug: is any substance other than water and food used to prevent, treat or
diagnose a disease.
For a drug to exert its effect on the body, it must reach its site of action on a
sufficient concentration. This is usually affected by "HOW" it enters the body
(Routes of administration).
Route of administration Dosage form
Describe the way by which the drug will
be introduced into the body.
Describe the pharmaceutical form
(shape) in which the drug will be
formulated to be administered.
Drug effects:
Local Systemic
Results from Direct application of the drug to the
desired site of action.
Advantage:
❖ Achieving high concentration of the
drug at the site of action
❖ Reduced systemic adverse
reactions
The entrance of the drug
into the circulatory system
and its transport to the site
of action.
Such as Eye/ nose/ skin/ lung ❖ Intravenous injection
❖ Absorbed into venous
circulation following
oral or other routes of
administration
Routes of drug administration with their related dosage forms differ in their ease of:
(Administration – Risks – Relative time to drug action) in order to suit the patients'
different clinical conditions.
Each route has its own advantages and disadvantages
Drugs are given orally usually to produce
Systemic effects Local effect in GIT
❖ The swallowed drug will be
absorbed from the GIT.
❖ The small intestine is the main site of
drug absorption because of its large
surface area and rich blood supply.
❖ Some drugs are partially absorbed
from stomach (Aspirin)
❖ If it is poorly absorbed.
❖ e.g: the antibiotic neomycin is given
to sterilize the gut before surgical
operations
Routes of drug administration
Dosage forms and routes
of drug administration

The amount of the drug that reaches the systemic circulation depends on:
Drug absorption Affected by:
1. pH of GIT
2. gastric emptying.
3. Intestinal motility.
4. Stability of drugs in the GIT.
5. Binding of drugs to GIT contents
Hepatic first pass metabolism Absorbed drugs will pass first through the portal
venous system to the liver, where they may be
metabolized with various extents before reaching the
systemic circulation.
Advantages:
Oral drug administration Highly acceptable and convenient to the patients.
Oral dosage forms Cheaper than other dosage forms.
Duration of action Can be prolonged
Disadvantages:
Oral administration Is not suitable in
❖ Emergency because of delayed onset of action
❖ comatose patients
Is not applicable for drugs destroyed
❖ By gastric acidity (e.g. penicillin)
❖ By gastric enzymes (e.g. insulin, and oxytocin)
is not used for drugs with extensive first pass
effect (e.g. testosterone)
is not suitable for drugs with very poor
absorption (e.g. gentamycin)
Some drugs may cause gastric irritation (e.g. aspirin)
Absorption of some
drugs
May be affected, delayed, or enhanced by the
presence or absence of food in the stomach
And whether they are given before or after
meals,
❖ e.g, most antibiotics are better given on empty
stomach to prevent interference with their
absorption by food.
Sometimes tablet taken
without or with small
quantity of water and
while the patient is in the
supine position
may lodge in the oesophagus and its absorption
is delayed
may cause ulceration specially in the elderly
(e.g. sustained release KCI )
Dosage forms for oral administration:
In general, they could be in a solid or liquid form.
Drugs administered in aqueous solution are mostly absorbed much more
rapidly than those administered in solid form because disintegration and
dissolution are not required.

A.Tablets:
❖ solid disc-like formulations
❖ prepared in the factories by mechanical compression of active drug
substance inert substances used as fillers or binders (e.g. lactose ,
calcium salts ,etc ... )
Uncoated tablets ❖ the most common type of tablets
❖ Is intended to be swallowed and to release the drug in
a relatively short time.
❖ They are therefore sometimes called immediate
release tablets.
❖ May be plain or scored.
Scored tablet is a tablet that has a score (fissure) that allows it
to be divided into two, three, or sometimes four equal parts.
requires that the active ingredient is homogenously
distributed throughout the tablet
Chewable tablets ❖ Are to be chewed and thus mechanically disintegrated
in the mouth.
❖ Thus flavoring and sweetening agents are important.
Effervescent tablets
‫فوار‬
contain active ingredients + mixture of acids and
carbonate, which release CO2 and produce
effervescence when mixed with water.
They are used for
❖ Large sized tablets that cannot be swallowed
❖ Drugs that is not easily dissolved in stomach
Lozenges ‫مستحلب‬ Dissolve slowly in the mouth and thus, release the drug
dissolved in the saliva.
They are mostly used for local soothing effect in the throat
Coated tablets
Are coated with a cover that
❖ protects the drugs from decomposition,
❖ masks the bad disagreeable taste or odour
❖ Facilitates swallowing.
Modified release
tablets
Delayed release tablets (enteric coated tablets): are
covered with substances that are
❖ Resistant to the acidic gastric juice
❖ But dissolve in the alkaline pH of the intestine.
Drug release is thus delayed. This type of tablets protects
❖ The acid-sensitive drugs from destruction by gastric
acid
❖ The gastric mucosa from irritant drugs
Extended release tablets: The drug within them is prepared as
pellets coated with a waxy film of different thickness so that
these pellets can dissolute gradually at variable speed along
the GIT
PlainScored

B. Capsules:
❖ They consist of oblong casing made of gelatine or similar substances that
contains the drug in a powder or granulated forms .
❖ Capsules can also be formulated to have modified release properties .
C.Syrups and mixtures :
In syrups In mixtures
the active ingredient (s) are
dissolved in a sugary solution
(syrup) containing additional
flavoring and coloring agents to
improve the taste and odour.
the drugs are simply suspended or emulsified.
❖ Suspension is a mixture of insoluble material
suspended in a liquid medium in the
presence of a suspending agent,
❖ Emulsion is a mixture of two immiscible
liquids that are made miscible by
emulsifying agents.
An example of suspending or emulsifying
agents is gum acacia.
Both emulsions and suspensions should be
shaken well before administration
D.Powders :
They are preparations of solid dry particles containing one or more active
substances that are generally administered in water or another suitable liquid.
Drugs are given in the form of small tablets or pellets to produce a systemic effect.
The drug is dissolved in saliva and absorbed through the buccal mucosa directly into
the systemic circulation avoiding passage through the liver.
It is used when :
❖ A rapid response is required , e.g. sublingual nitroglycerin can stop chest pain
due to ischemia of the cardiac muscle .
❖ The drug is either unstable at gastric pH Or extensively metabolized in the liver.
II. Sublingual route
Question ❖ Which is the best oral dosage form you think is more suitable for a drug with a bad
taste or odour? Coated tablets Or capsules
❖ When needed!! Patient can take safely half of which dosage form? Scored tablet

Advantages:
1.Drugs can produce a rapid effect and with smaller doses, because it is directly
introduced into the blood stream through the rich blood supply of the oral mucosa
2.Drugs bypass barriers of the GIT absorption and hepatic metabolism .
3.The effect can be terminated by spitting out the tablet
Disadvantages:
1. Drugs may be irritant to the mucous membranes .
2. Salivation promotes swallowing, thus, losing the advantage of this route.
3. This route is only suitable for a small number of drugs, which are effective in
small dose.
Rectal administration is used either to produce
local effects systemic effects
❖ Anti-inflammatory
drugs used in
ulcerative colitis and
astringent,
haemostatic
❖ Anti-inflammatory
agents used in
anorectal conditions
as haemorrhoids)
paracetamol for treatment of fever.
To achieve a systemic effect, the drug must be
dissolved and absorbed through the rectal
mucosa.
Drugs absorbed from
the upper rectum the lower rectum
❖ pass through the liver
❖ Are exposed to first
pass metabolism
❖ Before reaching the
systemic circulation
enter directly to the
systemic circulation
without passing
through the liver
Advantages:
1. useful for drugs
which are
destroyed by
❖ Intestinal enzymes
❖ The low pH in the stomach
❖ Are extensively inactivated by the liver
2. useful in ❖ case of vomiting
❖ patients who cannot swallow.
❖ unconscious patient.
❖ when cooperation is lacking (sedation in children).
3. It is advantageous
for drugs with
Bad taste and odour.
4. It is useful to Achieve rapid local effect as to relieve pain and
itching in haemorrhoids
Disadvantages:
1. It is inconvenient to the patient
2. Sometimes absorption may not
be regular,
especially if the rectum is full of stools
III. Rectal route

3. Rectal inflammation may occur
with
repeated use
Dosage forms for rectal administration
1. Suppositories
‫اللبوس‬
These are solid preparations intended to be inserted into
the rectum. They melt at the body temperature , releasing
the drugs.
2. Enemas
‫الشرجية‬ ‫الحقنة‬
These are solutions introduced into the rectum
Evacuation enemas Retention enemas
Applied to produce
local effect by
softening the feces
and distending the
bowel.
They are used in
preparations for
surgery, radiological
examinations, and
endoscopy
Enemas to be retained may be
used to provide
local effect systemic effect
in ulcerative
colitis of the
colon
nutritional
enemas
(Retention is achieved by
controlling the amount of the
fluid and the pressure by which
it is introduced into the rectum)
3. Creams,
Ointments, and
Gels
These are also available for application in localized
anorectal disorders.
N.B .: Suppositories intended for insertion into the vagina are called ovules.
❖ Now, it generally refers to administration of drugs by injections,
❖ While, the oral, sublingual, and the rectal routes are sometimes collectively
referred to as the enteral route.
By this route, a drug is injected through a needle into the body at various sites and
to various depths, therefore it includes different subtypes.
❖ It is generally used to produce a systemic effect,
❖ But sometimes it can produce a local effect according to the site of
injection.
IV. Parenteral route
Para entron
Beside Intestine
Outside the intestine and not by the way of the
alimentary tract

Parenteral administration is generally used under the following situations
1. Drugs that are poorly absorbed from the GIT
2. Drugs that undergo extensive hepatic first pass metabolism.
3. Drugs that are unstable in the GIT, such as insulin.
4. It can be used for the treatment of unconscious patients or when a rapid onset is
required.
Parenteral routes of administration include
1. Intradermal route:
Injection is made into the skin.
This route is used for:
❖ Testing for the sensitivity to the drugs, e.g. penicillin before their administration.
❖ Tuberculin test for diagnosis of tuberculosis.
❖ Vaccination, e.g. BCG vaccine (vaccine against tuberculosis)
2. Subcutaneous route (SC):
Injection is made in the subcutaneous tissues.
It is suitable for non-irritant drugs, which may be either in:
❖ Aqueous solution
❖ Fine suspension (to slow the absorption and prolong the duration of action, e.g.
long acting insulin preparations)
Advantages Disadvantages
Easy route for self-medication,
E.g. SC insulin for treatment of
diabetes mellitus
❖ Not suitable for large volume (should be less
than 2 ml), as it may be painful.
❖ Inadequate absorption in patient with shock,
because of cutaneous vasoconstriction
N.B: Vasoconstrictors, such as adrenaline, greatly decrease the rate of absorption from
SC injection. Therefore, adrenaline may be used with local anesthetics injection to
prolong their duration of action and to decrease their systemic absorption, and thus
their adverse reactions.
‫بم‬‫عني‬‫ان‬‫الـ‬Adrenaline‫بيعمل‬cutaneous vasoconstriction‫بنحقنها‬ ‫اللي‬ ‫األدوية‬ ‫امتصاص‬ ‫يقلل‬ ‫فبالتالي‬
locally by subcutaneous injection‫عشان‬‫كدا‬‫بنستخدمه‬‫مع‬‫الـ‬Local anesthetic drugs‫يقلل‬ ‫عشان‬
‫الـ‬ ‫في‬ ‫امتصاصها‬Systemic circulation‫تأثيرها‬ ‫يفضل‬ ‫ف‬locally

3. Intramuscular route (IM):
Injection is made deep into a large muscle, e.g.
❖ The deltoid muscle in the shoulder or
❖ Gluteus muscle in the buttocks.
Intramuscular route can accommodate volume of drug up to a maximum of 10
ml.
Drug given by intramuscular injection may be available as aqueous solution or
depot preparation.
Depot preparation is either a suspension of a drug in non-prolong the duration of action.
Advantages Disadvantages
❖ Provides more rapid absorption than
subcutaneous injection
soluble preparations are absorbed
within 10-20 minutes
❖ Suitable for irritant drugs
❖ The use of depot preparation allows
for prolonged action of some drugs,
e.g. long acting penicillin
❖ Not suitable for self-administration
❖ There is a risk of infection and
abscess formation
❖ Painful
4. Intravenous route (IV):
The injection of the drug solution is made directly into a vein so that it is diluted with
the venous blood. Only aqueous solution can be used.
Advantages
1. Large volume of the drug could be injected I.V.
2. The effect of the drug is immediate. SO
it is useful in emergency and with a highly predictable blood concentration.
3. It is suitable for administration of very irritant drugs since
❖ The walls of the blood vessels are insensitive to pain
❖ The drug is immediately diluted by the blood, e.g. administration of cytotoxic
drugs
4. Immediate stop of administration is possible (if unwanted effects occur) in I.V
infusion.
5. Drugs that are rapidly destroyed (short t1/2) can be infused continuously to
provide a steady state ( e.g. oxytocin ) plasma concentration.
N.B:
❖ By slow IV infusion, the concentration of the drugs in blood could be
adjusted by the control of the flow rate.
❖ Intravenous infusion is useful to maintain blood levels of drugs over a long
duration. )‫مباشرة‬ ‫الدم‬ ‫في‬ ‫أحقنه‬ ‫ما‬ ‫بدل‬ ‫محلول‬ ‫في‬ ‫الدوا‬ ‫أحط‬ ‫(يعني‬

Disadvantages
1. Rapid delivery of the drug to the plasma and tissues may lead to
unwanted effects. Therefore, it should be given slowly
2. It may lead to
❖ phlebitis (inflammation in the wall of veins)
❖ thrombophlebitis (thrombosis on top of inflammation of the wall of veins)
especially with prolonged infusion of irritant drugs
3. There is a risk of infection, if aseptic technique is not used
4. There is a risk of extravasation of drugs into the surrounding tissues
SC IM IV
Non-irritant Mild irritant Irritant
Aqueous and depot Aqueous and depot Aqueous only
5. Intra-arterial injection:
❖ Injection is made into the lumen of an artery.
❖ The artery is chosen as close as possible to the site of action desired.
❖ This is an example of parenteral drug administration to achieve a local
effect.
❖ Certain anticancer agents may be administered by intra-arterial injection
into the artery going to the malignant tumor.
6. Intra-thecal injection:
❖ It is given in the subarachnoid space to
achieve a local effect.
7. Intra-cardiac injection:
This type of injection is used only in cardiac resuscitation, e.g. adrenaline in cardiac
arrest.
8. Intra-articular injection:
Injection introduced directly into particular joint to produce a local effect e.g. intra -
articular steroids in certain types of arthritis.

Dosage forms for parenteral administration include
❖ ampoules that contain a single dose.
❖ vials that contain single or multiple doses.
❖ I.V infusion.
❖ I.V canula.
Parenteral formulations should be:
❖ sterile
❖ pyrogen free (free of any foreign proteins which may lead to fever)
❖ Of suitable pH.
❖ Of suitable osmotic pressure
Topical administration is the route by which drugs are directly applied to the body
surface including the skin and mucous membranes, e.g , eye and nose.
It is commonly used for
❖ local drug delivery,
❖ but some specific formulations can allow for systemic effect.
Dosage forms used for topical administration
❖ Ointments
❖ Creams
❖ Gel
❖ Pastes
• Are semisolid preparations.
• May be applied to the skin or mucous membranes e.g.
eye ointment and gel.
• The base of the preparation incorporates the drug (s),
which are intended to produce local effect.
V. Topical route
Question
❖ In case of emergency, which parenteral route do
you think is the most suitable?
✓ Intravenous injection

Gel Ointment Creams
Useful in hairy
areas
Greasy, sticky
providing a
protective film on
non-hairy areas
Oil-in-water
emulsions
*Spread more easily
than ointments and
are easier to remove.
*They are especially
suitable for exudative
lesions as in burns.
❖ Drops
❖ Sprays
❖ Lotions
• Are aqueous solutions
• Applied to the eye, ear, nose, or even the skin.
Eye drops Ear drops Nasal drops & sprays
designed for
application to the
mucosal surface of
the eye
(conjunctival sac)
applied to the
external auditory
canal.
applied to the nasal
cavity.
Some nasal
formulations can allow
for systemic
absorption and are
intended to produce
systemic effect, e.g.
Oxytocin
These preparations should be sterile, isotonic, stable, and
non-irritant.
Transdermal
patch
(Transdermal
delivery
system)
the drug is applied to the skin to be absorbed into the general
circulation producing a systemic effect through the use of a
transdermal patch.
o This patch is a plaster like material, which is pasted to the
skin
o It contains a reservoir from which the drug may diffuse
and is absorbed through the skin to the systemic
circulation
o This type of preparation offers the advantage that a drug
depot will be administered over extended period of time in
a manner similar to an infusion.
o In addition to the ease of application, the effect of the
drug can be terminated simply by removal of the patch
Characteristics of drugs that can be given transdermal are:
❖ Good penetration through the skin.
❖ Effective in very small doses.
❖ Possessing a wide therapeutic margin (a wide range
between therapeutic and toxic blood levels)
For example:
❖ Nitroglycerin skin patch used to relieve chest pain due to
cardiac ischemia
❖ Nicotine skin patch used to stop smoking habit.

By this route, the drug in the form of gas or volatile liquid will go into the respiratory
passages with inspiration.
Drugs may be introduced into the respiratory passages to produce either
A local effect A systemic effect
As in treatment of bronchial asthma As in general anesthesia
In this later condition, the lung itself will be
❖ the route of administration
❖ As well as, the site of drug excretion
The rapid absorption of drugs through the alveoli is due to
❖ Their wide surface area
❖ High vascularity
❖ Thin porous membrane.
Dosage forms for administration by inhalation
1. Inhaler Is a device that delivers drugs directly into the
patient's lungs in the form of aerosol or fine powder
particles that the patient breathes in.
2. Nebulizer It is a device used to administer an aerosol
(through a mask) of a drug solution kept inside a
reservoir
3. Inhalational gases General anesthetic, e.g. sevoflurane is
administered through a face mask or tracheal
tube connected to an anesthetic delivery system.
VI. Inhalation route
❖ All preparations are used for local
effect except transdermal patch that
induces systemic effect.
❖ Nasal sprays may be designed to
provide a local or systemic effect
❖ For systemic effect, the drug must reach the systemic circulation whether
✓ Directly as in I.V injection
Or
✓ Indirectly through the portal pulmonary, skin, muscle, sublingual, or
nasal mucosal blood vessels in other routes of administration.
❖ For local effect, the drug is directly delivered to its target site and its
absorption to the systemic circulation is usually minimal or negligible

Route of administration Time until effect Route of administration Time until effect
Intravenous 30-60 sec. Inhalation 2-3 min.
Sublingual 3-5 min. Intramuscular 10-20 min.
Rectal 5-30 min. Subcutaneous 15-30 min.
Oral 30-90 min. Transdermal (topical) Variable (min. To H.)
Choose ONE correct answer
1. If a drug has extensive first pass metabolism in the liver, which dosage form has
the advantage of bypassing this metabolism?
a. Extended release tablet
b. Enteric coated tablet
c. Transdermal patch
d. Delayed release capsule
2. In the emergency room (ER), a patient came unconscious with hyperglycemic
coma that should be treated with insulin, by which route would you administer
insulin to this patient to achieve rapid control of blood glucose level?
a. Intravenous infusion
b. Oral route
c. Subcutaneous injection
d. Sublingual route
3. A girl has a small lesion in her scalp, which needs administration of a topical anti
- inflammatory drug. Which preparation is the best to be used in this situation?
a. Anti - inflammatory cream
b. Anti - inflammatory gel
c. Anti - inflammatory ointment
d. Anti - inflammatory patch
4. Which of the following hormones cannot be taken orally due to extensive first
pass metabolism?
a. Oestrogen
b. Progesterone
c. Testosterone
d. Cortisone
5. Which of the following types of injection is the most suitable for administration of
an antibiotic that is highly irritant in aqueous solution?
a. Intramuscular
b. Intravenous
c. Subcutaneous
d. Intradermal
Questions

6. Which of the following preparations may have a short duration of action?
a. Transdermal patch
b. Intramuscular depot preparation
c. Extended release tablet
d. Sublingual tablet
1. C 2. A 3. B 4. C 5. B 6. D

BACKGROUND:
A prescription is an instruction from a prescriber to a dispenser to supply
certain quantity of a specific substance (s) or drug (s) to a specific patient.
The prescriber is usually a physician.
The dispenser )‫الصيدلية‬ ‫في‬ ‫الروشتة‬ ‫هيصرف‬ ‫اللي‬(is not always a pharmacist, but can
be a pharmacy technician, an assistant, or a nurse.
Every country has its own standards for the minimum information required for
a prescription and its own laws and regulations to define which drugs require
a prescription and who is entitled to write it.
In general, on writing a prescription, the following should be stated:
WHAT is to be given, to WHOM , by WHOM.
To WHOM ❖ Patient's name
❖ Age
❖ Address
By WHOM ❖ Doctor's name
❖ Number
❖ Address
❖ Doctor's signature
WHAT is to be given Instructions on;
❖ HOW MUCH should be given.
❖ HOW OFTEN,
❖ By WHICH ROUTE
❖ And, sometimes for HOW LONG.
Basically, all the drugs should require prescription before being dispensed.
However, few drugs and most of nutritional supplements can be available to
consumers without prescription. Such drugs are termed non - prescription drugs or
Over the counter (OTC) drugs.
‫و‬ ‫روشتة‬ ‫غير‬ ‫من‬ ‫بتتصرف‬ ‫الفيتامينات‬ ‫زي‬ ‫األدوية‬ ‫بعض‬ ‫في‬ ‫انه‬ ‫بمعني‬‫األدوية‬‫اسمها‬ ‫دي‬prescription drugs-non
.Over the counter (OTC) drugsor
A drug can be approved to be an OTC if:
❖ Its benefits outweigh its risks, (Benefits >Risks)
❖ The potential for misuse and abuse is low.
❖ The consumer can use it for self-diagnosed conditions.
❖ It can be adequately labelled.
‫الـ‬ ‫العلبة‬ ‫علي‬ ‫مكتوب‬ ‫بيبقي‬dose‫ال‬ ‫و‬ ‫ايه‬ ‫قد‬side effects‫هكذا‬ ‫و‬
❖ Health practitioners are not needed for the safe and effective use of the
product.
Prescription writing

with the exception of OTC products, all other medications are termed prescription
drugs, whose dispensing requires a prescription.
‫الـ‬ ‫غير‬ ‫تاني‬ ‫دوا‬ ‫أي‬OTC‫اسمه‬ ‫بيبقي‬Prescription drugs‫س‬ ‫روشتة‬ ‫فس‬ ‫يبقي‬ ‫تتصرف‬ ‫عشان‬ ‫الزم‬ ‫يعني‬‫كانوا‬ ‫واء‬
controlled drugs-nonOrcontrolled
Non-controlled drugs Controlled drugs
Non addicting
‫إدمان‬ ‫إلي‬ ‫يؤدي‬ ‫ال‬ ‫استخدامها‬ ‫يعني‬
Addicting
‫إمان‬ ‫إلي‬ ‫يؤدي‬ ‫استخدامها‬ ‫سوء‬ ‫أدوية‬ ‫يعني‬(Abuse –
dependence)
The specifications of the prescription vary according to the degree of " harm " induced
by the drug, mainly its potential to drug dependence or abuse, such drugs are termed
controlled drugs.
‫بيسبب‬ ‫الدوا‬ ‫لو‬ ‫يعني‬Abuse or dependence‫اسمه‬ ‫دا‬ ‫يبقي‬controlled drug
REQUIREMENTS FOR WRITING A FULL PRESCRIPTION FOR NON-CONTROLLED DRUGS:
On writing any prescription, the following items should be fulfilled:
1. Date
2. Prescriber
information
1. Doctor's name.
2. Phone number.
3. Address.
They should be clearly written (or commonly pre-printed )
on the top of the prescription form .
3. Patient information 1. Patient's name
2. Age
3. Address
4. Diagnosis
5. Superscription ℞ This is a symbol for the word Recipe (take thou, Latin),
which is addressed to the patient.
6. Inscription it includes
1. the name
2. Dosage form of the drug prescribed
3. The specific strength of that dosage form
7. Subscription It contains:
1. The amount of the drug to be dispensed by the
pharmacist.
2. The instructions for the patient, to be written on the
container by the pharmacist.
For example,
❖ The number of tablets to be taken
❖ The frequency of administration
❖ sometimes the timing, especially in relation to food
intake, as well as other drugs or food to be avoided
8. Doctor's signature

N.B:
If more than one drug is prescribed, each of them should have its own
superscription, inscription, and subscription.
It is also sometimes important to determine whether the pharmacist can supply
a substitute drug or not. The number of allowed prescription refill can be also
indicated.
N.B: some countries, like EGYPT, legally mandate prescription only for Controlled drugs
---------------------------------------------------------------------------------------------------
REQUIREMENTS FOR WRITING A FULL PRESCRIPTION FOR CONTROLLED DRUGS:
❖ There are special prescription requirements for drugs classed as "controlled
drugs".
❖ These requirements are in part to monitor the distribution of drugs that are
potentially harmful when misused, to prevent patients from developing a drug
dependence, and to prevent those who misuse drugs from obtaining a
prescription by deception.
E.g: Diazepam – Morphine - Alprazolam
On writing a prescription for controlled drugs, the following items should be fulfilled
over the typical prescription form:
It should be ❖ properly dated
❖ Written in ink
Doctor's information ❖ Doctor's name
❖ address
❖ phone number
❖ Registration number
Patient's information ❖ Patient's name
❖ Age (Age is mandatory)
❖ Address.
Patient's name:
Patient's address:
Patient's age:
Doctor's name:
Doctor's address & Phone number:
Date:
Diagnosis: Simple headache.
℞
Paracetamol tablets 500 mg/tablets
Send 10 tablets
One tablet to be taken when necessary
Doctor's signature
Prescriber informationPatient information
Superscription
Subscription
Inscription
Name Dosage form Strength
Pharmacological
name
Instructions for the patient
Controlled drugs: Any drug or therapeutic agent with a potential for abuse or addiction

Diagnosis
No abbreviations, and no figure numbers All doses, number of ampoule, or tablets
should be written in letters
Doctor's full signature at the end of the prescription
The prescription is dispensed once and kept by the pharmacist
‫ال‬ ‫شبه‬ ‫تقريبا‬ ‫يعني‬prescription of non-controlled drugs‫تتكتب‬ ‫الزم‬ ‫األرقام‬ ‫و‬ ‫اختصارات‬ ‫مفيش‬ ‫هنا‬ ‫انه‬ ‫باختالف‬
‫في‬ ‫غلطة‬ ‫أي‬ ‫ألن‬ ‫بالحروف‬prescription of controlled drugs‫تسبب‬ ‫ممكن‬addiction
Example of controlled drugs prescription
Prescribing a drug to relieve severe types of pain requires the use of a class of
analgesics known as opioid analgesics, Severe pain could be due to cancer,
myocardial infarction, surgical trauma, fractures .... etc.
Examples of opioid analgesics are.
❖ Morphine Fifteen milligrams per ampoule. I.V – I.M – SC
❖ Oxycodone Ten milligrams per ampoule. I.V – I.M – SC – Orally
❖ Pentazocine Sixty milligrams per ampoule. I.V – I.M
Any of these drugs could be given However
intravenously or intramuscularly ❖ morphine and oxycodone could
also be given subcutaneously,
❖ Oxycodone is available as oral
tablets
Opioid analgesics are different in efficacy and the choice of one drug from another
depends on the severity of pain and the presence of certain contraindications , e.g ..
asthma, labour, benign prostatic hyperplasia ... etc. morphine is better avoided.
Patient's name:
Patient's age:
Patient's address:
Doctor's name:
Doctor's address:
Doctor's registration number:
Date:
Diagnosis: Cancer pain.
℞
Oxycodone Hydrochloride ampoule Ten milligrams per ampoule
Send two ampoules
One ampoule injected intravenous when required
Doctor's Full signature
Prescriber informationPatient information
Superscription
Subscription
Inscription
Name Dosage form Strength
Pharmacological
name
Instructions for the patient

Abbreviations used in medical prescriptions
Abbreviation Word in Latin Meaning
Qd Quaque die Once a day
Bid Bis in die 2x a day
Tid Ter in die 3x a day
qid Quarter in die 4x a day
Hs Hora Somni At bedtime
Ac Post cibum After meals
Ac Anti cibum Before meal
PO Per os Oral
Prn Pro re nata As needed
‫الـ‬ ‫عدد‬ ‫هنحسب‬ ‫ازاي‬ ‫طب‬capsules‫للمريض‬ ‫هتتصرف‬ ‫اللي‬‫؟‬
‫الـ‬ ‫دوا‬ ‫هنكتب‬ ‫اننا‬ ‫افترضتنا‬ ‫لو‬strength‫بتاعته‬250 mg/capsule‫هياخد‬ ‫المريض‬ ‫النفروض‬ ‫و‬500 mg‫اليوم‬ ‫في‬
‫ياخد‬ ‫الزم‬ ‫انه‬ ‫كدا‬ ‫معني‬ .....2 capsules / day‫لمدة‬ ‫مثال‬ ‫الدوا‬ ‫أخد‬ ‫لو‬ ‫و‬3‫أيا‬‫كدا‬ ‫يبقي‬ ‫م‬
‫الـ‬ ‫عدد‬ ‫نحسب‬ ‫نيجي‬ ‫لما‬ ‫ف‬capsules‫لمدة‬ ‫اليوم‬ ‫في‬ ‫كبسولتين‬ ‫أخد‬ ‫لو‬ ‫انه‬ ‫هنالقي‬3‫كدا‬ ‫معني‬ ‫أيام‬‫انه‬‫محتاج‬6 capsules
‫دوا‬ ‫أي‬ ‫علي‬ ‫دا‬ ‫تطبق‬ ‫تقدر‬According to the strength‫الدوا‬ ‫علبة‬ ‫علي‬ ‫المكتوب‬
PRINCIPLES OF SAFE PRESCRIBING
Be clear about the reasons
for prescribing
❖ Establish an accurate diagnosis whenever possible.
❖ Be clear in what way the patient is likely to gain
from the prescribed medicines
Take into account the
patient's medication history
before prescribing
Obtain an accurate list of
❖ Current and recent medications (including OTC
and alterative medicines),
❖ Prior adverse drug reactions,
❖ Drug allergies from the patient and their carers
Take into account other
factors that might alter the
benefits and risks of
treatment.
For example,
❖ Physiological changes with age and pregnancy
❖ or impaired kidney, liver functions
Select effective, safe , and
cost-effective medicines
individualized for each
patient
❖ Choose the best
formulation, dose , frequency, route of administration,
and duration of treatment
❖ Select medicines with regard to costs and needs
of the patients
2 x 1 x 3No. Of
capsules
Per day
No. Of
days

Adhere to national
guidelines and local
formularies where
appropriate
Be aware of guidance produced by respected bodies,
but always consider the individual needs of the patient
Identify how the beneficial
and adverse reactions of
treatment can be assessed
❖ Understand how to alter the prescription as a result of
this information.
❖ Know how to report adverse drug reactions via the
Yellow Card scheme
Prescribe within the limitations of your
❖ knowledge
❖ Skills
❖ Experience
Write clear legal
prescriptions
Give patients important information about
❖ How to take the medicine,
❖ What benefits might arise,
❖ Adverse reactions,
❖ Any monitoring tool that is required
Be aware of common
factors that cause
medication errors and know
how to avoid them
Prescribing errors can occur as a result of:
❖ Inadequate knowledge of the patients and their
clinical status.
❖ Inadequate drug knowledge.
❖ Calculation errors.
❖ Illegible handwriting.
❖ Drug name confusion.
❖ Poor history taking.
Illegible prescription: The following example shows how drug name has been
misinterpreted as a result of poor handwriting. A prescription for Amoxil (an
antibiotic) was misread as Daonil (an oral hypoglycemic). Accordingly, the
patient suffered permanent harm as a result of prolonged hypoglycemia.
‫دوا‬ ‫كاتب‬ ‫الطبيب‬ ‫يعني‬Amoxil‫للمريض‬‫بداله‬ ‫صرف‬ ‫و‬ ‫غلط‬ ‫قراه‬ ‫الصيدلي‬ ‫ف‬ ‫واضح‬ ‫مش‬ ‫خطه‬ ‫لكن‬ ‫و‬Daonil‫بيوطي‬ ‫دوا‬ ‫دا‬ ‫و‬
‫الدم‬ ‫في‬ ‫السكر‬‫هي‬ ‫المريض‬ ‫فبالتالي‬‫من‬ ‫يعان‬ ‫و‬ ‫غلط‬ ‫دوا‬ ‫اخد‬hypoglycemia
Dose units: As well as drug names, dose units can be misinterpreted.
This is especially important
❖ In paediatrics
❖ In drugs with wide variation in the dose that can be administered.
For example Abbreviation of the word units to IU resulted in the administration of 10 -
fold overdose of insulin when prescriptions for 6IU were misread as 61 units.

‫اختصار‬ ‫يعني‬international unit‫بيكون‬IU‫مثال‬ ‫االنسولين‬ ‫جرعة‬ ‫كتب‬ ‫الطبيب‬ ‫لما‬ ‫ف‬6IU‫اتقرت‬61 unit‫انه‬ ‫كدا‬ ‫معني‬
‫هياخد‬10‫الـ‬ ‫أضعاف‬dose
-----------------------------------------------------------------------------------------------------------------------------
Examples of prescriptions:
Poor handwriting
Poor handwriting
Poor handwriting
Inadequate drug knowledge

Poor handwriting
No doctor's name
Poor handwriting
Duphaston can be
misinterpreted by Dupatalin
Liverin can be
misinterpreted by Librax

Background:
❖ Therapeutic and toxic effects of drugs result from their interactions with
molecules in the body.
❖ Most drugs act by non-covalent interaction with specific macromolecules in
ways that alter the macromolecules' biofunctional activities.
❖ Such macromolecules are termed RECEPTORS
‫يدي‬ ‫الدوا‬ ‫عشان‬ ‫أنه‬ ‫بمعني‬effect‫كان‬ ‫سواء‬therapeutic or toxic‫بيدخ‬ ‫لما‬ ‫هو‬ ‫ف‬‫في‬ ‫و‬ ‫جزئيات‬ ‫مع‬ ‫بييتفاعل‬ ‫الجسم‬ ‫ل‬
‫تعمل‬ ‫انها‬ ‫طريق‬ ‫عن‬ ‫بتتفاعل‬ ‫األدوية‬ ‫بعض‬covalent bonds-non‫ال‬ ‫هي‬ ‫دي‬ ‫الجزئيات‬ ‫و‬ ‫دي‬ ‫الجزئيات‬ ‫مع‬Receptor
‫ال‬ ‫و‬receptor‫ليه‬2 domains
❖‫ال‬ ‫في‬ ‫هيمسك‬ ‫و‬ ‫برة‬ ‫من‬ ‫اللي‬drug‫اسمه‬Ligand- binding domain
❖‫اسمه‬ ‫جوة‬ ‫من‬ ‫اللي‬ ‫و‬Effector domain
❖‫كل‬ ‫ان‬ ‫عارفين‬ ‫كلنا‬ ‫طبعا‬receptor‫بيكون‬‫ليه‬endogenous substance‫في‬ ‫طبيعي‬ ‫موجودة‬ ‫مادة‬ ‫يعني‬
‫ال‬ ‫في‬ ‫تمسك‬ ‫لما‬ ‫الجسم‬receptor‫بتدي‬effect
❖‫الـ‬ ‫في‬ ‫مسك‬ ‫الدواء‬ ‫فلو‬Receptor‫الـ‬ ‫نفس‬ ‫عطي‬ ‫و‬maximum effect‫ال‬ ‫بيديه‬ ‫اللي‬endogenous
substance‫اسمه‬ ‫يبقي‬Agonist
❖‫ال‬ ‫نفس‬ ‫عطي‬ ‫لو‬ ‫و‬effect‫لكن‬ ‫و‬less than the maximum effect‫اسمه‬ ‫يبقي‬Partial agonist
❖‫ال‬ ‫في‬ ‫مسك‬ ‫الدوا‬ ‫لو‬ ‫و‬receptor‫اداش‬ ‫ما‬ ‫و‬effect‫يبقي‬ ‫خالص‬Antagonist‫بيعمل‬ ‫بكدا‬ ‫و‬inhibition to
the receptor
Dose-Effect Relationship

‫الـ‬Acetylcholine (Ach)‫هو‬ ‫عارفين‬ ‫احنا‬ ‫ما‬ ‫زي‬neurotransmitter‫علي‬ ‫بيشتغل‬muscarinic and
nicotinic receptors
‫نـ‬ ‫اننا‬ ‫مطلوب‬ ‫دا‬ ‫السكشن‬ ‫في‬Investigate the dose-effect relationship‫باستخدام‬ ‫هنعمله‬ ‫دا‬ ‫و‬microlab
stimulation software‫المعمل‬ ‫في‬ ‫هنعملها‬ ‫المفروض‬ ‫كنا‬ ‫*الخطوات‬‫الكمبيوتر‬ ‫علي‬*‫الكلية‬ ‫في‬ ‫السكشن‬ ‫حضرنا‬ ‫كنا‬ ‫لو‬
‫بنجيب‬ ‫اننا‬ ‫الفكرة‬piece of intestine‫برة‬ ‫عليها‬ ‫نشتغل‬ ‫و‬*In vitro*‫دوا‬ ‫عليها‬ ‫نجرب‬ ‫و‬‫دي‬ ‫الحالة‬ ‫في‬ ‫هنا‬ ‫هو‬ ‫*اللي‬
Ach*‫بنالحظ‬ ‫و‬magnitude of contraction
Experimental design ‫الفكرة‬ ‫نفهم‬ ‫عشان‬ ‫نفهمها‬ ‫الزم‬ ‫بس‬ ‫الخطوات‬ ‫في‬ ‫هنتسأل‬ ‫مش‬
‫بنجيب‬piece of isolated guinea pig ileum‫ال‬ ‫جسم‬ ‫برة‬ ‫عليها‬ ‫نشغل‬ ‫و‬animal‫يعني‬*in-vitro*
‫بواسطة‬ ‫خطواتها‬ ‫هنشوف‬ ‫كنا‬ ‫لكن‬ ‫و‬ ‫دي‬ ‫التجربة‬ ‫هنعمل‬ ‫مكناش‬ ‫الكلية‬ ‫في‬ ‫حتي‬ ‫كنا‬ ‫لو‬ ‫طبعا‬ ‫و‬microlab software
‫اننا‬ ‫بما‬ ‫و‬‫ال‬ ‫علي‬ ‫بنشتغل‬intestine‫انها‬ ‫تقدر‬ ‫و‬ ‫ساعات‬ ‫لمدة‬ ‫سليمة‬ ‫عليها‬ ‫نحافظ‬ ‫عشان‬ ‫عوامل‬ ‫شوية‬ ‫فيه‬ ‫يكون‬ ‫فالزم‬ ‫الجسم‬ ‫برة‬
‫للدوا‬ ‫تستجيب‬
Requirements for working intestine in-vitro:
1. Nutrient medium (Tyrode's solution)
2. Temperature of organ bath (37 ℃)
3. Mild degree of muscle tension.
4. Oxygenation with a mixture of (95% O2 + 5% CO2)
+2+ MgCl2NaCl + KCl + CaCl
+ Glucose3NaHCO

‫للـ‬ ‫بالنسبة‬Microlab software
1.‫بنختار‬ ‫و‬ ‫البرنامج‬ ‫بنفتح‬isolated
ileum
2.‫علي‬ ‫بنضغط‬ ‫بعدين‬ ‫و‬Experiment
3. Select "Acetylcholine" From the "Agonist" list.
4. Click on Bath conc. and write the desired
concentration (it's suggested to start with using
1e-9 mol/L, which equals1 nanomol/L)
5. Press on "Apply" button to add the agonist, the
trace will assume the "on" state.
6. After 10 to 20 seconds, press on "wash" to return to
normal concentrations, then press the "off" button to stop recording until you
prepare for the next concentration.
7.‫من‬ ‫الخطوات‬ ‫نكرر‬ ‫بعدين‬ ‫و‬3–6‫الـ‬ ‫نزود‬ ‫و‬concentration‫مرة‬ ‫كل‬ ‫في‬
8.‫ال‬ ‫فيه‬ ‫جدول‬ ‫في‬ ‫النتايج‬ ‫نحط‬ ‫بعدين‬ ‫و‬
Concentration and effect
Students activity 1
❖ 2e-9 mol/L = 2 nmol/L
❖ 8e -8 mol/L = 80 nmol/L
‫الـ‬ ‫تكون‬ ‫الزم‬ ‫النتايج‬ ‫نرسم‬ ‫هنيجي‬ ‫لما‬ ‫اننا‬ ‫بالك‬ ‫خلي‬unit‫واحدة‬‫لـ‬ ‫كله‬ ‫هنحول‬ ‫ف‬nmol/L‫؟؟؟‬ ‫ازاي‬ ‫دا‬ ‫طب‬
❖9-9 = 10-e‫و‬‫لـ‬ ‫نحولها‬ ‫نيجي‬ ‫لما‬nmol/L‫هنشيل‬9-e‫الوحدة‬ ‫جنبه‬ ‫و‬ ‫الرقم‬ ‫نحط‬ ‫و‬nmol/L
o E.g: 2e-9 mol/L = 2 nmol/L
❖8-8=10-e‫من‬ ‫أكبر‬ ‫يعني‬9-10‫هنشيل‬ ‫نحولها‬ ‫نيجي‬ ‫لما‬ ‫ف‬8-e‫في‬ ‫نضربه‬ ‫و‬ ‫الرقم‬ ‫نحط‬ ‫و‬10‫الوحدة‬ ‫جنبه‬ ‫و‬
nmol/L
❖7-= 107-e‫و‬‫لـ‬ ‫نحولها‬ ‫نيجي‬ ‫لما‬nmol/L‫هنشيل‬7-e‫الوحدة‬ ‫جنبه‬ ‫و‬ ‫الرقم‬ ‫نحط‬ ‫و‬nmol/L

9.‫في‬ ‫النتايج‬ ‫ارسم‬ ‫بعدين‬ ‫و‬
Concentration-effect curve
‫علي‬ ‫تاني‬ ‫النتائج‬ ‫نرسم‬ ‫بعدين‬ ‫و‬semi-log scale‫نحسب‬ ‫و‬
EC50
‫الـ‬Semi-log dose effect curve‫بيحول‬
rectangular hyperbola curve‫لـ‬
Symmetrical sigmoid curve
N.B:
❖ The effect (magnitude of
acetylcholine-induced concentration)
can be observed in the trace.
❖ To get accurate results, fix the duration
of muscle relaxation (wash period)
N.B:
❖ At a sub-threshold concentration → no
response
❖ ↑ Dose → ↑ response
❖ until Max. response → Furthur ↑ in Dose →
no ↑ in response
This produces a rectangular
hyperbola curve
Symmetrical sigmoid curve
EC50: is the concentration of an agonist, which produces 50% of the maximum possible
effective response for that agonist.
Rectangular hyperbola curve
Due to saturation of all the receptors

Potency Efficacy
Is the amount of drug required to
produce an effect of given intensity.
Is the ability of a drug to produce a
maximum response.
Differences in drug potency are
evaluated by comparing EC50 (or ED50)
values.
Differences in drug efficacy are
evaluated by comparing differences in
maximal response at high drug doses or
concentrations
‫في‬ ‫عملنا‬ ‫ما‬ ‫زي‬ ‫هنعمل‬ ‫هنا‬students activity1‫هنضيف‬ ‫اننا‬ ‫الفرق‬ ‫بس‬*antagonist*Atropine‫ال‬ ‫مع‬Ach
1. Select "Acetylcholine" from the agonist list, begin
with concentration of 1e-8, then gradually
increase the dose to make a concentration-
effect curve as you have made in the former
section.
2. Select "Atropine" from the antagonist list, write a
concentration of 1e-8 mol/L for atropine.
3. Repeat the same concentrations of acetylcholine
used in concentration-effect curve in the
presence of the antagonist (atropine).
4.‫هنزود‬ ‫بس‬ ‫جدول‬ ‫في‬ ‫النتائج‬ ‫نحط‬ ‫بعدين‬ ‫و‬‫خانة‬‫الـ‬ ‫تركيز‬Atropine
Students activity 2

5.‫نرسم‬ ‫بعدين‬ ‫و‬Curve for agonist alone‫نرسم‬ ‫و‬Curve for agonist + antagonist in the
same semi-log graph
6.‫قيمة‬ ‫نحسب‬ ‫و‬EC50 For Ach alone‫و‬‫نحسب‬EC50 in the presence of atropine
7. Finally, compare between both curves regarding EC50 and Maximal effect (Emax)
❖ A competitive antagonist combines with the same receptor site as the agonist.
❖ Competitive antagonists do not stimulate the receptor when they bind to it, but
they will prevent the access of an agonist to it and thus, block its action.
o The competitive antagonist can be displaced from the binding site by an excess of
the agonist.
Therefore, the maximum effect of an agonist can still be achieved in the presence of a
competitive antagonist if a sufficient dose or concentration of the agonist is used.
o The competitive antagonist lowers the potency of the agonist (EC50) but does not
alter its efficacy (Emax)
‫الـ‬ ‫ضيفنا‬ ‫احنا‬ ‫فاتت‬ ‫اللي‬ ‫التجربة‬ ‫في‬Atropine‫يعتبر‬ ‫هو‬ ‫و‬Antagonist *blocker*‫الـ‬ ‫عمل‬ ‫بيضاد‬ ‫يعني‬Ach‫عن‬
‫الـ‬ ‫في‬ ‫يمسك‬ ‫بيرح‬ ‫انه‬ ‫طريق‬Receptors‫المفر‬ ‫أللي‬‫و‬‫الـ‬ ‫فيها‬ ‫يمسك‬ ‫ض‬Ach‫الـ‬ ‫تأثير‬ ‫نلغي‬ ‫ممكن‬ ‫احنا‬ ‫لكن‬ ‫و‬atropine
‫الـ‬ ‫تركيز‬ ‫نزود‬ ‫اننا‬ ‫طريق‬ ‫عن‬Ach‫الـ‬ ‫ف‬Ach‫الـ‬ ‫في‬ ‫يمسك‬ ‫و‬ ‫هيغلب‬Receptor‫ال‬ ‫ألن‬ ‫ودا‬Atropine‫يعتبر‬
Reversible competitive antagonist‫الـ‬ ‫من‬ ‫أفصله‬ ‫أقدر‬ ‫يعني‬receptor‫فيه‬ ‫ماسك‬ ‫ألنه‬reversibly
ِ
‫الـ‬ ‫فب‬ ‫هنالحظ‬Curve‫ناحية‬ ‫اتحرك‬ ‫انه‬‫اليمين‬
‫ال‬ ‫ان‬ ‫مدا‬ ‫معني‬potency‫احتجنا‬ ‫يعني‬ ‫قلت‬
‫من‬ ‫أعلي‬ ‫تركيز‬Ach‫للـ‬ ‫نوصل‬ ‫عشان‬EC50
‫ان‬ ‫كدا‬ ‫معني‬‫الـ‬EC50‫زادت‬
‫ال‬ ‫لكن‬ ‫و‬Efficacy‫اتغيرتش‬ ‫ما‬

‫في‬ ‫عملناه‬ ‫اللي‬ ‫نفس‬ ‫هنعمل‬ ‫هنا‬Students activity 2‫الـ‬ ‫هنبدل‬ ‫لكن‬ ‫و‬ ‫بالظبط‬Atropine‫بـ‬Papaverine‫دا‬ ‫و‬
‫بردوا‬Antagonist‫الـ‬ ‫بيعمله‬ ‫اللي‬ ‫عكس‬ ‫بيعمل‬ ‫يعني‬Ach‫بيعمل‬ ‫يعني‬Muscle relaxation‫ال‬ ‫عن‬ ‫يختلف‬ ‫لكنه‬ ‫و‬
Atropine‫في‬competitive antagonist-non‫بيستخدم‬ ‫كدا‬ ‫عشان‬as antispasmodic
‫ايه‬ ‫يعني‬ ‫طب‬non-competitive antagonist‫؟؟؟‬
❖ The primary effect of a non-competitive antagonist is a reduction in the maximal
effect produced by the agonist.
❖ In contrast to a competitive antagonist, the effect of a non-competitive
antagonist cannot be reversed by simply increasing the concentration of the
agonist
Atropine with Ach Papaverine with Ach
EC50 Shifted to the right Constant
Efficacy Constant Decreased
Students activity 3
‫الـ‬ ‫بيقلل‬ ‫لما‬ ‫يعني‬maximal effect of the agonist‫تركيز‬ ‫نزود‬ ‫اننا‬ ‫طريق‬ ‫عن‬ ‫تاني‬ ‫أزوده‬ ‫مبقدرش‬‫الـ‬agonist‫لسببين‬ ‫دا‬ ‫و‬
1.‫الـ‬ ‫نفس‬ ‫في‬ ‫بيمسك‬ ‫انه‬ ‫إما‬Receptor‫الـ‬ ‫فيه‬ ‫بيمسك‬ ‫اللي‬Agonist‫لكن‬ ‫و‬Irreversibly‫هيسيبه‬ ‫ما‬ ‫عمره‬ ‫يعني‬
‫حصل‬ ‫مهما‬
2.‫أي‬ ‫في‬ ‫مسك‬ ‫أنه‬ ‫إما‬ ‫و‬Site‫في‬ ‫تاني‬signaling pathway‫الـ‬ ‫من‬ ‫مقربش‬ ‫يعني‬receptor‫ال‬ ‫بوظ‬ ‫ف‬pathway
‫كله‬
ِ
‫الـ‬ ‫فب‬ ‫هنالحظ‬Curve‫انه‬‫الـ‬Efficacy
‫قلت‬
‫الـ‬ ‫لكن‬ ‫و‬EC50‫تقريبا‬‫ثابتة‬

Put (True) or (False) regarding the following statements about agonist /antagonist
interaction.
1. In the presence of atropine, the concentration - effect curve of ACh Is shifted to
the right
2. Competitive antagonists markedly lower the maximum effect of the agonist.
3. Atropine has no effect on the EC50 of Ach
4. In the presence of papaverine, the Emax of ACh is decreased
5. The EC50 of the agonist is typically decreased in the presence of competitive
antagonist.
1. True 2. False 3. False 4. True 5. False
Put (True) or (False) regarding the following statements about the composition of Tyrod's
solution.
1. Similar in composition to extracellular fluid
2. Similar in composition to intracellular fluid
3. Essentially a sodium chloride solution
4. Essentially a potassium chloride solution
5. Should contain glucose and oxygen to support metabolism of smooth muscle
cells
1. True 2. False 3. True 4. False 5. True
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Pharmacology

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Pharmacology