Uploaded byLudy Mae Nalzaro,BSM,BSN,MN
PHARMA=DRUGS FOR NEUROLOGIC DISORDERS
Myasthenia gravis is caused by a defect in neuromuscular transmission resulting in muscle weakness. Drugs used to treat it include neostigmine, pyridostigmine, and edrophonium. Neostigmine inhibits the breakdown of acetylcholine to improve nerve impulse transmission, but can cause excessive stimulation or paralysis. Pyridostigmine has a longer duration than neostigmine. Edrophonium is used diagnostically to differentiate myasthenic from cholinergic crisis.
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PHARMA=DRUGS FOR NEUROLOGIC DISORDERS
- 1. DRUGS FOR MYASTHENIAGRAVIS Neostigmine Pyridostigmine Edrophonium 1
- 2. MYSTENIA GRAVIS • Chronicmuscular disease caused by a defec in neuromuscular transmission characterize by gradual destruction of Ach receptors. • characterized by fatigue and severe weakness of skeletal muscles 2
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- 5. DRUGS FOR MYASTHENIAGRAVIS 1. NEOSTIGMINE ACTION: – Inhibit destruction of Ach facilitating transmission of impulse across myoneural junction PHARMACOKINETICS: • Poorly absorbed orally • Can cross blood-brain barrier affect CNS • Duration of action 2-4hrs 5
- 6. DRUGS FOR MYASTHENIAGRAVIS 1. NEOSTIGMINE CONTRAINDICATION: • Obstruction of GI tract, urinary tract • Peptic ulcer disease • Asthma • Coronary insufficiency • Hyperthyroidism 6
- 7. DRUGS FOR MYASTHENIAGRAVIS 1. NEOSTIGMINE ADVERSE EFFECTS: • EXCESSIVE MUSCARINIC STIMULATION – Excessive salivation – Increased gastric secretion – Increased tone and motility of GI – Urinary urgency – Bradycardia – Sweating 7
- 8. DRUGS FOR MYASTHENIAGRAVIS 1. NEOSTIGMINE ADVERSE EFFECTS: • NEUROMUSCULAR BLOCKADE – Accumulation of Ach in amount sufficient to produce depolarizing neuromuscular blockade – Results in paralysis of respiratory muscles 8
- 9. DRUGS FOR MYASTHENIAGRAVIS 2. PYRIDOSTIGMINE (Mestinon) • Inhibit destruction of Ach • Has longer duration than neostigmine • * adverse reaction: decreased HR, diarrhea and hypotension 9
- 10. DRUGS FOR MYASTHENIAGRAVIS 3. EDROPHONIUM (Tensilon) • A drug with very short duration of action (10-20 min) • PRIMARILY USED AS A DIAGNOSTIC AGENT to differentiate myasthenic crisis from cholinergic crisis • If the drug alleviates symptoms = MYASTHENIC CRISIS • If the drug intensifies symptoms = CHOLINERGIC CRISIS 10
- 11. DRUGS FOR ALZHEIMERSDISEASE Cognex Aricept 11
- 12. ALZHEIMERS DISEASE • Progressivedisorder involving neuronal degeneration in the cortex leading to loss of memory and inability to perform activities of daily living 12
- 13. DRUGS FOR ALZHEIMERSDISEASE 1. COGNEX • 1st cholinesterase inhibitor approved for Alzheimer’s disease • Administered orally • Food decreases absorption • Blood levels peak in 2 hrs, with short half- life of 3hrs, must be administered 4x a day • Cause liver damage with high dose 13
- 14. DRUGS FOR ALZHEIMERSDISEASE 2. ARICEPT • Current agent of choice • Well-absorbed orally • Eliminated mainly in urine and partly in bile • Has longer plasma half-life of 6hrs • Administered 1x a day 14
- 15. Alzheimer’s – MedicalManagement • Medication to treat symptoms – Memory:Cognex, Aricept – Agitation: Mellaril, Haldol • Supplements – Folic Acid & Vitamin B12 – Low fat diet – NSAIDS
- 16. Medications Cholinesterase inhibitors usedto treat mild to moderate dementia • Tacrine hydrochloride (Cognex) • Donepezil hydrochloride (Aricept) • Rivastigmine (Exelon) Medications to treat depressions • Tranquilizers for severe agitation • Thioridazine (Mellaril) • Haloperidol (Haldol) • Antioxidants: vitamin E, anti-inflammatory agents, estrogen replacement therapy in women
- 17. DRUGS FOR SEIZURES Hydantoins Succinimides 17
- 18. SEIZURES • Sudden andrapid firing of electrical impulse from neuron located in brain • Generalized seizures begin in 1 area and spread throughout the different areas of the brain • Partial seizures involve only 1 area of the brain and remain localized. 18
- 19. DRUGS FOR SEIZURES 1.HYDANTOINS • Stabilize nerve membranes and limit spread of excitability from the initiating focus Drugs: 1. phenytoin (Dilantin) = prototype drug 2. ethotoin 3. fosphenytoin 4. mephenytoin 19
- 20. DRUGS FOR SEIZURES 1.HYDANTOINS INDICATION: – Tonic-clonic seizures PHARMACOKINETICS: • Slowly absorbed in small intestine • Excreted in urine • Highly protein bound, thus, decrease in serum protein or albumin can increase free phenytoin serum level • Half-life is 22 hrs 20
- 21. DRUGS FOR SEIZURES 1.HYDANTOINS CONTRAINDICATIONS: • Psyche conditions • Bradycardia • Hepatic failure CAUTION: • Pregnancy – can cause birth defects and bleeding tendencies 21
- 22. DRUGS FOR SEIZURES 1.HYDANTOINS ADVERSE EFFECTS: 1. GINGIVAL HYPERPLASIA 2. Neurologic and psyche SE like slurred speech, confusion, depression and thrombocytopenia 3. Hyperglycemia = effect of drug inhibiting release of insulin Less severe AE: 1. Alopecia 2. Hirsutism 3. Nystagmus 4. N&V 22
- 23. DRUGS FOR SEIZURES 1.HYDANTOINS SPECIAL NURSING CONSIDERATIONS: 1. Administer IV infusion of phenytoin directly into a large vein. – Maybe diluted in NSS; dextrose solution should be avoided-cause drug precipitation 2. Do not administer continuously – 50 mg can be administered in a period of 1min for adult and 25mg in elderly 23
- 24. DRUGS FOR SEIZURES 1.HYDANTOINS SPECIAL NURSING CONSIDERATIONS: 3. Monitor local irritation at injection site 4. Monitor drug levels as ordered; therapeutic level 10-20mcg/ml 5. Enteral feeding interfere oral absorption. Stop feeding for 2 hrs before and after administration 24
- 25. DRUGS FOR SEIZURES 2.SUCCINIMIDES ACTION: – Suppress the abnormal electrical activity in the brain associated in petit mal or absence seizure INDICATION: – Control of absence seizures 25
- 26. DRUGS FOR SEIZURES 2.SUCCINIMIDES – Absorbed in GI tract – Peak levels of 1-7hrs – Metabolized in liver – Excreted in urine – Able to cross placenta and enter breast milk 26
- 27. DRUGS FOR SEIZURES 2.SUCCINIMIDES CONTRAINDICATIONS: – Renal/hepatic disease – Pregnancy and lactation – Intermittent porphyria 27
- 28. DRUGS FOR SEIZURES 2.SUCCINIMIDES ADVERSE EFFECTS: • Depressing effects in CNS: – Depression, drowsiness, ataxia, insomnia, HA and blurred vision • Bone marrow suppression and dermatologic reaction: – Pruritus, urticaria, alopecia and Steven Johnson’s syndrome 28
- 29. DRUGS FOR SEIZURES 2.SUCCINIMIDES GENERAL NURSING CONSIDERATIONS: 1. Discontinue at any sign of hypersensitivity reaction, liver dysfunction or severe skin rash – to prevent potential fatal reaction. 2. Administer with food – to alleviate GI upset 3. Women of child-bearing age should be referred for counseling – may cause serious damage to fetus 29
- 30. DRUGS FOR SEIZURES 2.SUCCINIMIDES GENERAL NURSING CONSIDERATIONS: 4. Suggest wearing of MedicAlert bracelet – to alert emergency workers about the use of the drugs 5. Monitor CBC before and periodically during therapy – to detect bone marrow suppression early and provide appropriate interventions 30
- 31. DRUGS FOR SEIZURES 3.DRUGS FOR PARTIAL/FOCAL SEIZURES – Carbamazepine (Tegretol) – Clorazepate (Tranxene) – Felbamate (Felbatol) – Gabapentin (Neurontin) – Lamotrigine (Lamictal) – Levetiracetam (Keppra) 31
- 32. DRUGS FOR SEIZURES 3.DRUGS FOR PARTIAL/FOCAL SEIZURES ACTION: – Control partial or focal seizures either by acting on the sodium and calcium channels or increasing GABA activity 32
- 33. DRUGS FOR SEIZURES 3.DRUGS FOR PARTIAL/FOCAL SEIZURES CONTRAINDICATION: • Bone marrow suppression • Hepatic dysfunction • Pregnancy and lactation • Presence of renal stones ADVERSE EFFECTS: • CNS depression: drowsiness, fatigue, weakness, confusion and HA 33
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- 35. NEUROMUSCULAR ABNORMALITIES MUSCLE SPASM •Result of musculoskeletal injury – Muscle stretches beyond capacity • Characterized by painful contraction of muscles • Spasms are felt when sensory impulses travel fro the spinal cord to the site of injury, passing the motor nerves to cause muscle contraction • Blood flow to the muscle is disrupted causing lactic acid accumulation and pain 35
- 36. MUSCLE SPASTICITY • Permanentcondition caused by neuronal damage in the CNS • Hyperactive stimulation of the muscles resulting to loss of muscle coordination • Ex in MULTIPLE SCLEROSIS – Lesion in CNS interrupts nerve impulse resulting to progressive muscle weakness 36
- 37. CENTRALLY-ACTING MUSCLE RELAXANTS Prototype: Baclofen Baclofen Carisoprodol Chlorphenesin Chlorzoxasone Cyclobensapine Metaxalone Methocarbamol 37
- 38. CENTRALLY-ACTING MUSCLE RELAXANTS ACTION: •Interfere with neuromuscular communication in CNS to cause muscle relaxation INDICATION: • Multiple Sclerosis • Cerebral palsy • Any trauma in spinal cord 38
- 39. CENTRALLY-ACTING MUSCLE RELAXANTS •Rapidly absorbed orally • Peak 2-3hrs • Can cross blood brain barrier and crosses the placenta CAUTION: – CNS depression – Cardiac dysfunction – Hepatic and renal dysfunction – Pregnancy and lactation 39
- 40. CENTRALLY-ACTING MUSCLE RELAXANTS NURSINGCONSIDERATIONS: • Discontinue if + hypersensitivity or liver dysfunction. – If using baclofen, taper the drugs gradually within 1-2 weeks to prevent dev’t of psychoses • If receiving baclofen using IV pump, instruct client about the pump and the rationale for the need to monitor frequently • Report if client’s respiratory status deteriorates 40
- 41. DIRECT-ACTING MUSCLE RELAXANTS Prototype: Dantrolene 41
- 42. DIRECT-ACTING MUSCLE RELAXANTS ACTION: •Relaxes muscles thru direct action on the skeletal muscle fibers • Dantrolene prevents muscular contraction by inhibiting the release of calcium from the muscle fibers 42
- 43. DIRECT-ACTING MUSCLE RELAXANTS INDICATION: •Tx of upper motor neuron disorders: MYASTHENIA GRAVIS & CEREBRAL PALSY • Acute tx of malignant hyperthermia (complication of general anesthesia=severe muscle contraction) 43
- 44. DIRECT-ACTING MUSCLE RELAXANTS •Only 30% of oral dose is absorbed, reaching peak plasma concentration in 5 hrs • Liver metabolizes the drug • Crosses the placenta and breastmilk 44
- 45. DIRECT-ACTING MUSCLE RELAXANTS ADVERSEEFFECTS: • Muscle weakness : drooling, slurred speech, drowsiness, dizziness, malaise • GI effects: diarrhea, constipation, GI bleeding, dysphagia, n&v • Aplastic anemia and leucopenia 45
- 46. DIRECT-ACTING MUSCLE RELAXANTS NURSINGCONSIDERATIONS: 1. Assess for lactose intolerance before drug administration – Dantrolene capsules contain lactulose 2. Administer with food or milk to avoid GI distress 3. Advise to wear appropriate protective clothing sunscreen when exposed to direct sunlight 46
- 47. DIRECT-ACTING MUSCLE RELAXANTS NURSINGCONSIDERATIONS: 4. Provide safety precautions in cases of severe muscle weakness 5. Provide frequent skin care to prevent skin breakdown 6. Inform client that hepatitis is 1 of the dangerous adverse effects – Loss appetite, n&v, yellow skin or eyes and changes in urine and stool color. 47