Medication List 5 PDF

Classic Anticonvulsants Phenytoin (Dilantin®) Use: Partial seizures, generalized tonic-clonic seizures (GTC), status epilepticus. Pharmacodynamics: Prolongs the inactivated state of sodium channels, inhibits glutamate release, and enhances GABA release. Pharmacokinetics:...

Classic Anticonvulsants Phenytoin (Dilantin®) Use: Partial seizures, generalized tonic-clonic seizures (GTC), status epilepticus. Pharmacodynamics: Prolongs the inactivated state of sodium channels, inhibits glutamate release, and enhances GABA release. Pharmacokinetics: o 90% protein-bound. o Nonlinear metabolism (small dose changes can lead to large serum level fluctuations). o Metabolized by the liver (CYP3A4 inducer). Details: o Therapeutic Level: 10–20 mcg/mL (total), 1–2 mcg/mL (free). o Adverse Effects: § Dose-related: Nystagmus, diplopia, ataxia, sedation. § Non-dose related: Gingival hyperplasia, hirsutism, rash, hepatotoxicity. § Long-term: Osteomalacia (recommend vitamin D supplementation). o Avoid in pregnancy due to teratogenic effects. Carbamazepine (Tegretol®, Carbatrol®) Use: Partial seizures, generalized tonic-clonic seizures. Pharmacodynamics: Prolongs inactivated state of sodium channels. Pharmacokinetics: o Induces CYP3A4 and auto-induces its own metabolism. o T½: Initially 36 hours, then 8–12 hours with continued use. Details: o Therapeutic Level: 4–12 mcg/mL. o Adverse Effects: § Common: Diplopia, GI upset, drowsiness, ataxia. § Severe: Aplastic anemia, agranulocytosis (monitor CBC regularly). § Rare: Stevens-Johnson Syndrome (HLA-B*1502 screening recommended in Asian populations). o Strong enzyme inducer → multiple drug interactions. Phenobarbital (Luminal®) Use: Generalized tonic-clonic seizures, status epilepticus. Pharmacodynamics: Enhances GABA-mediated inhibition and inhibits sodium, calcium, and chloride channels.  Pharmacokinetics: o Long half-life: 75–125 hours. o Induces CYP3A4 (many drug interactions). Details: o Therapeutic Level: 10–40 mcg/mL. o Adverse Effects: § Sedation, cognitive impairment, hypotension (IV form), ataxia, hyperactivity. § High potential for abuse and dependence. o Avoid in pregnancy due to teratogenic effects. Valproic Acid (Depakote®, Depakene®) Use: Absence seizures, generalized tonic-clonic, myoclonic, atonic, partial seizures. Pharmacodynamics: Increases GABA activity, prolongs sodium channel inactivation. Pharmacokinetics: o Highly protein-bound (90%). o Inhibits liver enzymes (CYP2C9, CYP3A4). Details: o Therapeutic Level: 50–100 mcg/mL. o Adverse Effects: § Common: GI distress, weight gain, tremor, sedation, hair loss. § Severe: Hepatotoxicity, pancreatitis, thrombocytopenia. o Highly teratogenic (neural tube defects, cardiac anomalies). Modern Anticonvulsants Levetiracetam (Keppra®) Use: Generalized tonic-clonic, myoclonic, and partial seizures. Pharmacodynamics: Modulates synaptic vesicle proteins to reduce neurotransmitter release. Pharmacokinetics: o 100% bioavailable orally. o Minimal liver metabolism (not CYP dependent). Details: o Therapeutic Level: Not routinely monitored. o Adverse Effects: § Somnolence, asthenia, ataxia, agitation, psychosis. o Minimal drug interactions, making it a preferred option. Lamotrigine (Lamictal®) Use: Generalized tonic-clonic, partial, absence, myoclonic, and atonic seizures. Pharmacodynamics: Inhibits sodium channels and weakly inhibits calcium channels. Pharmacokinetics: o Hepatic metabolism. o Dose adjustments required with valproate (inhibitor) and enzyme inducers. Details: o Therapeutic Level: 3 mcg/mL. o Adverse Effects: § Common: Dizziness, headache, nausea. § Severe: Rash, including Stevens-Johnson Syndrome (SJS/TEN). o Risk of serious skin reactions is reduced with slow titration. Topiramate (Topamax®) Use: Partial and generalized tonic-clonic seizures, Lennox-Gastaut syndrome. Pharmacodynamics: Inhibits sodium channels, potentiates GABA activity, inhibits glutamate receptors. Pharmacokinetics: o Renally excreted. o Moderate CYP3A4 interactions. Details: o Therapeutic Level: Not routinely monitored. o Adverse Effects: § Common: Cognitive impairment ("Dopamax"), weight loss, paresthesia. § Severe: Nephrolithiasis, metabolic acidosis, glaucoma. o Monitor serum bicarbonate for metabolic acidosis. Gabapentin (Neurontin®) Use: Adjunct for partial seizures (not first-line). Pharmacodynamics: Modulates GABA release and inhibits calcium channels. Pharmacokinetics: o Renal excretion (adjust dose in renal failure). o Absorption decreases at high doses. Details: o Therapeutic Level: 10–40 mcg/mL. o Adverse Effects: § Common: Somnolence, dizziness, weight gain, peripheral edema. o Minimal drug interactions. Pregabalin (Lyrica®) Use: Partial seizures (not first-line), neuropathic pain. Pharmacodynamics: More potent version of gabapentin; binds to calcium channels. Pharmacokinetics: o Renally excreted. o Linear pharmacokinetics (dose-dependent plasma levels). Details: o Adverse Effects: § Somnolence, dizziness, weight gain, peripheral edema. o Schedule V controlled substance. Lacosamide (Vimpat®) Use: Partial seizures. Pharmacodynamics: Preferentially inhibits slow inactivation of sodium channels. Pharmacokinetics: o Minimal liver metabolism. o Low drug interactions. Details: o Adverse Effects: § Dizziness, headache, diplopia. o Titrate slowly to avoid dizziness. Generalized Seizure Medications Ethosuximide (Zarontin®) Use: Absence seizures (first-line). Pharmacodynamics: Selectively inhibits calcium channels in the thalamus. Pharmacokinetics: o Hepatic metabolism. o Minimal drug interactions. Details: o Therapeutic Level: 50–100 mcg/mL. o Adverse Effects: § Common: GI distress, lethargy, dizziness. § Rare: Psychosis.