General Prescribing Guidelines.pptx

GENERAL PRESCRIBING
GUIDELINES
Dr.Navaneethakrishnan PharmD.,
Assistant Professor
Department of Pharmacy Practice

Introduction
Prescribing medication is a complex and important aspect of
healthcare that requires careful consideration of various factors. Here are
some general prescribing guidelines:
Follow evidence-based guidelines:
When prescribing medication, it is important to follow
evidence-based guidelines that are backed by research and clinical trials.
This helps to ensure that the medication is safe and effective.
Consider the patient's medical history:
Before prescribing medication, it is important to consider the
patient's medical history, including any allergies, previous illnesses, and
current medications. This can help to avoid potential interactions or adverse
effects.

Introduction
Start with the lowest effective dose:
It is recommended to start with the lowest effective dose when
prescribing medication. This helps to minimize the risk of side effects and
adverse reactions.
Monitor the patient's response:
After prescribing medication, it is important to monitor the
patient's response and adjust the dosage or medication as needed. This
helps to ensure that the medication is working effectively and that the
patient is not experiencing any adverse effects.
Educate the patient:
It is important to educate the patient about the medication,
including its benefits and potential side effects. This helps to ensure that the
patient is fully informed and can make informed decisions about their
healthcare.

Introduction
Consider non-pharmacological options:
In some cases, non-pharmacological options such as lifestyle
changes or alternative therapies may be appropriate. These options should
be considered before prescribing medication, if appropriate.
Prescribe within scope of practice:
When prescribing medication, it is important to stay within the
scope of practice for your profession and follow relevant laws and
regulations.
These guidelines are not exhaustive and may vary depending
on the specific patient and medication. Therefore, it is important to consult
with a healthcare professional before prescribing medication.

General Prescribing Guidelines for Paediatrics
Prescribing medication for pediatric patients requires special
attention and considerations. Here are some general prescribing guidelines
for pediatric patients:
Accurate diagnosis:
As with adult patients, accurate diagnosis is essential before
prescribing medication for pediatric patients. This includes a thorough
assessment of the patient's symptoms, medical history, physical
examination, and any necessary laboratory tests.
Weight-based dosing:
Dosage of medication for pediatric patients should be calculated
based on the child's weight. The dosage should be calculated carefully to
ensure the medication is neither over-dosed nor under-dosed.

Age-appropriate medications:
Different medications and dosages may be appropriate for different
age groups of pediatric patients. It is important to consider the age of the
patient when selecting medications and dosages.
Formulations:
Medications may come in different formulations, such as liquid or
chewable tablets, that are easier for children to take. It is important to
consider the formulation when selecting medication for pediatric patients.
Safety:
Safety should always be the top priority when prescribing medication
for pediatric patients. Medications should be selected carefully to avoid any
adverse effects, and dosages should be adjusted based on the patient's
response.

Education:
Education is important when prescribing medication for pediatric
patients. Parents or guardians should be informed about the medication's
benefits, potential side effects, and instructions for administration.
Monitoring:
Monitoring the patient's response to medication is essential for
pediatric patients. Children may not be able to express their symptoms
accurately, so it is important to monitor their response to medication and
adjust the dosage or medication as needed.
Interactions with other medications:
Pediatric patients may be taking other medications, so it is important
to consider potential interactions when prescribing medication. Any
potential interactions should be carefully assessed and monitored.

Example for a pediatric patient with ear infection
Accurate diagnosis:
The child is diagnosed with acute otitis media (ear infection).
Weight-based dosing:
The antibiotic medication is prescribed based on the child's
weight.
Age-appropriate medications:
The medication is selected based on the child's age and the
severity of the ear infection.
Formulations:
The medication is available in a liquid form that is easier for the
child to take.

Example for a pediatric patient with ear infection
Safety:
The medication is selected based on the child's medical history, any
allergies, and potential interactions with other medications.
Education:
The parents or guardians are educated about the medication,
including how to administer it, potential side effects, and when to contact a
healthcare provider.
Monitoring:
The child's symptoms are monitored, and the medication may be
adjusted or changed if necessary.

When prescribing medications to pediatric patients, it is important to
consider the absorption, distribution, metabolism, and excretion (ADME) of
the drug to ensure that it is effective and safe.
Absorption
 Infants and young children have a higher gastric pH, which can affect
drug absorption. For acid-sensitive drugs, such as penicillin, the dose may
need to be adjusted accordingly.
 Enteral feeding or the use of feeding tubes may impact drug absorption. It
is important to consider the timing of drug administration in relation to
feeding.
 Some medications may require higher doses in children due to differences
in body weight and surface area.

Distribution
 Children have a higher percentage of body water than adults, which can
affect drug distribution. Hydrophilic drugs may have a larger volume of
distribution, while lipophilic drugs may have a smaller volume of
distribution in children.
 The protein-binding capacity of neonates and infants is lower than that of
adults, which can affect drug distribution. For highly protein-bound
drugs, this may result in a higher free drug concentration and increased
risk of toxicity.
Metabolism
 Hepatic metabolism is less efficient in neonates and infants due to the
immaturity of the liver. This can lead to slower metabolism of some
medications, resulting in longer half-lives and increased risk of toxicity.
 Age-related differences in enzyme activity and expression may affect drug
metabolism. It is important to consider the pharmacokinetic profiles of
individual drugs to ensure that doses are appropriate for children.

Excretion
Renal function is lower in neonates and infants, which can affect drug
excretion. Doses may need to be adjusted for drugs that are primarily
renally excreted.
The immature blood-brain barrier may affect the excretion of some
medications. This may result in a longer half-life and increased risk of
toxicity for drugs that are eliminated by the central nervous system.
Overall, pediatric prescribing requires careful consideration of
ADME factors to ensure that drugs are administered safely and effectively.
Dosing regimens may need to be adjusted based on age, weight, organ
function, and other individual patient factors.

 Pediatric dosing guidelines are important to ensure that medications are
administered safely and effectively in children.
 Dosage calculations in pediatrics are typically based on body weight, age,
or body surface area, and may be adjusted based on organ function,
comorbidities, and other individual patient factors.
Here are some general guidelines for pediatric dosing:
Body weight-based dosing:
 Most medications are dosed based on body weight, in milligrams per
kilogram (mg/kg).
 The recommended dose may vary depending on the age of the child, as
infants and young children may have different body weight ranges for a
given age compared to older children and adolescents.
 For example, the dosing range for acetaminophen in children aged 2-11
years is 10-15 mg/kg/dose, while the dosing range for adolescents aged
12-17 years is 325-650 mg/dose.

Body weight-based dosing
Dosage based on mg/kg:
To calculate the dose of a medication based on body weight in milligrams
per kilogram (mg/kg), use the following formula;
Dose = Weight (kg) x Dose (mg/kg)
For example, if the recommended dose of acetaminophen is 10 mg/kg and a child
weighs 20 kg, the dose would be: Dose = 20 kg x 10 mg/kg = 200 mg
Dosage based on mg/kg/day:
Some medications may be dosed based on a daily dose in milligrams per
kilogram per day (mg/kg/day). To calculate this dosage, use the following
formula;
Daily dose = Weight (kg) x Daily dose (mg/kg/day)
For example, if the recommended daily dose of amoxicillin for a child is 40
mg/kg/day, and a child weighs 25 kg, the daily dose would be: Daily dose = 25
kg x 40 mg/kg/day = 1000 mg/day. This total daily dose can then be divided into
multiple doses to be given throughout the day.

Body weight-based dosing
Young's rule, Fried's rule, and Clark's rule are three commonly used methods to
calculate pediatric medication dosages. The formulas for each rule are as follows:
Fried's Rule: This rule calculates the pediatric dose based on the child's weight.
Pediatric Dose = (Weight in kg ÷ 50) x Adult Dose
For example, if the adult dose is 500mg and the child weighs 30kg, the pediatric
dose would be:
Pediatric Dose = (30 ÷ 50) x 500mg = 500mg x 0.6 = 300mg
Clark's Rule: This rule calculates the pediatric dose based on the child's weight.
Pediatric Dose = (Weight in lbs ÷ 150) x Adult Dose
For example, if the adult dose is 500mg and the child weighs 66lbs, the pediatric
dose would be:
Pediatric Dose = (66 ÷ 150) x 500mg = 500mg x 0.44 = 220mg

Age-based dosing
 Some medications may be dosed based on age rather than body weight.
This is typically the case for liquid formulations or medications that are
difficult to accurately dose by weight.
 For example, ibuprofen suspension is dosed at 5-10 mg/kg/dose for
children aged 6 months to 11 years.
Young's Rule:
This rule calculates the pediatric dose based on the child's age.
Pediatric Dose = (Age / Age + 12) x Adult Dose
For example, if the adult dose is 500mg and the child is 5 years old, the
pediatric dose would be:
Pediatric Dose = (5 ÷ 5 + 12) x 500mg = 500mg x 0.29 = 145mg

Body surface area-based dosing
 Some medications may be dosed based on body surface area (BSA), which
is calculated using the child's height and weight.
 This is typically the case for chemotherapy drugs and other medications
with narrow therapeutic indices.
 The recommended dose may be expressed as mg/m2 or as a fixed dose for
a specific BSA range.
Body surface area (BSA) is a measure of the total surface area
of the body and is often used as a basis for dosing certain medications in
pediatric patients. The most commonly used formula for calculating BSA in
children is the Mosteller formula, which is as follows:
BSA (m2) = (Height (cm) x Weight (kg)) / 3600

To use this formula, first measure the child's height in centimeters and
weight in kilograms. Then, plug these values into the formula to calculate
BSA in square meters (m2).
For example, if a child is 1.2 meters tall and weighs 30 kg, the BSA
calculation would be:
BSA = (120 cm x 30 kg) / 3600 = 1.0 m2
Dilling's rule is a method for calculating the pediatric dosage of
medications based on body surface area.
Pediatric Dose = (BSA of child ÷ 1.73) x Adult Dose
In this formula, BSA refers to body surface area, which is calculated
based on the child's height and weight. The value of 1.73 represents the
average body surface area of an adult.

Once BSA is calculated, the appropriate dose of a medication can be
determined based on the recommended dose per square meter. This dose
can be calculated using the following formula:
Dose = BSA (m2) x Dose per square meter
For example, if the recommended dose of a medication is 10 mg/m2 and the
calculated BSA is 1.0 m2, the dose would be:
Dose = 1.0 m2 x 10 mg/m2 = 10 mg
It is important to use the appropriate formula for each medication and
to double-check calculations to avoid medication errors.
Additionally, it is important to consider the patient's age, clinical
status, and other factors when determining the appropriate dose. A pediatric
pharmacist or other healthcare provider can assist in ensuring accurate
dosing for pediatric patients.

Dose adjustments based on organ function:
 In children with impaired renal or hepatic function, dosing may need to be
adjusted to prevent accumulation of medications or their metabolites.
 For example, the dosing of vancomycin in children with impaired renal
function may need to be adjusted based on their estimated glomerular
filtration rate (eGFR).
It is important to follow specific dosing guidelines for each
medication and to consult with a pediatric pharmacist or other healthcare
provider if there are questions about dosing or administration.

General Prescribing Guidelines for Geriatrics
Prescribing medications for geriatric patients can be challenging due
to age-related changes in physiology, multiple comorbidities, and
polypharmacy. Here are some general prescribing guidelines for geriatrics:
Start low and go slow: Begin with the lowest effective dose and titrate
slowly to avoid adverse effects and drug interactions.
Be aware of age-related changes in pharmacokinetics: Elderly patients may
have decreased liver and kidney function, resulting in slower drug
metabolism and elimination. Adjust the dose and dosing frequency
accordingly.
Consider the patient's comorbidities: Elderly patients often have multiple
chronic conditions that require medication. Be aware of potential drug
interactions and adverse effects.
Simplify the medication regimen: Consider deprescribing medications that
are no longer necessary or that may be causing more harm than benefit.
Simplifying the medication regimen can improve medication adherence and
reduce the risk of adverse effects.

Monitor for adverse effects:
Elderly patients are more susceptible to adverse effects from
medications. Monitor for adverse effects and adjust the dose or discontinue
the medication as needed.
Be aware of the risk of polypharmacy:
Elderly patients may be taking multiple medications from multiple
healthcare providers, increasing the risk of drug interactions and adverse
effects. Review the medication regimen regularly to ensure that it is
appropriate and necessary.
Consider non-pharmacologic interventions:
Non-pharmacologic interventions, such as exercise, physical therapy,
and dietary changes, may be appropriate for treating certain conditions in
geriatric patients.

Provide clear instructions:
Provide clear instructions to the patient or caregiver on how to take
the medication, including the dose, frequency, and any special instructions
or precautions.
Monitor for medication adherence:
Elderly patients may have difficulty remembering to take
medications or may have physical limitations that make it difficult to take
medications as prescribed. Monitor for medication adherence and address
any barriers to adherence.
Follow up regularly:
Follow up with the patient regularly to assess the effectiveness of the
medication and any adverse effects. Adjust the medication regimen as
needed.

Example for an elderly patient with chronic pain
Accurate diagnosis:
The patient is diagnosed with chronic pain due to osteoarthritis.
Evidence-based treatment:
The patient is prescribed a medication that has been shown to be
effective in treating chronic pain.
Treatment goals:
The goal of treatment is to reduce pain and improve the patient's
quality of life.
Dosage and administration:
The medication is prescribed at a starting dose based on the
patient's age, weight, and any other medical conditions, and the dosage
may be adjusted over time based on the patient's response.

Example for an elderly patient with chronic pain
Monitoring:
The patient's pain levels and any potential side effects are monitored
regularly, and the medication dosage may be adjusted if needed.
Education:
The patient is educated about the medication, including how to take
it, potential side effects, and the importance of monitoring pain levels and
any potential side effects.
Interactions with other medications:
Potential interactions with other medications the patient is taking are
carefully considered, and the medication may be adjusted or changed if
necessary.

Absorption
 Age-related changes in the gastrointestinal tract can affect the absorption
of medications in geriatric patients. For example, decreased gastric acidity
and slower gastric emptying can delay drug absorption. It's important to
consider these factors when selecting the appropriate dosage form and
administration route for geriatric patients.
Distribution
 Changes in body composition, such as decreased muscle mass and
increased adipose tissue, can affect drug distribution in geriatric patients.
Additionally, changes in protein binding and blood flow can also impact
drug distribution. It's important to consider these factors when selecting
the appropriate dosage and dosing frequency for geriatric patients.

Metabolism
 Age-related changes in liver function can affect drug metabolism in
geriatric patients. For example, decreased hepatic blood flow and
decreased activity of drug-metabolizing enzymes can result in slower drug
metabolism and longer drug half-lives. It's important to consider these
factors when selecting the appropriate dosage and monitoring for
potential adverse effects.
Excretion
 Age-related changes in renal function can affect drug excretion in geriatric
patients. For example, decreased glomerular filtration rate can result in
slower drug clearance and longer drug half-lives. It's important to
consider these factors when selecting the appropriate dosage and
monitoring for potential adverse effects.

General Prescribing Guidelines.pptx

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