Week 11 Reverse Flashcards
Bind to GABA-A receptors, enhancing the inhibitory effect of GABA by increasing chloride influx, leading to neuronal hyperpolarization and decreased excitability.
Benzodiazepines: MOA in Seizure Management
Used acutely for seizure emergencies like status epilepticus (e.g., diazepam, lorazepam). Chronic use is limited due to tolerance; clobazam and clonazepam may be used for specific seizure types.
Benzodiazepines: Acute vs. Chronic Use
IV lorazepam preferred for status epilepticus. Diazepam is available in rectal and intranasal formulations for out-of-hospital use.
Benzodiazepines: Routes of Administration
Chronic use may lead to tolerance and decreased effectiveness. Typically reserved for short-term or adjunctive therapy.
Benzodiazepines: Tolerance and Long-Term Use
Blocks voltage-gated sodium channels, stabilizing neuronal membranes and preventing repetitive firing.
Phenytoin: Mechanism of Action
Fosphenytoin is a water-soluble prodrug of phenytoin, safer for IV/IM use with fewer infusion-related complications.
Fosphenytoin vs. Phenytoin
Binds to synaptic vesicle protein SV2A. Minimal drug interactions, renally excreted, fewer cognitive side effects. May cause mood changes.
Levetiracetam: MOA and Clinical Advantages
Selection based on seizure type, side effect profile, drug interactions, and patient-specific factors.
Antiepileptic Drugs: Risks and Benefits
Highly protein-bound; nonlinear pharmacokinetics. Small dose changes can lead to large increases in serum levels.
Phenytoin: Distribution
Many anti-epileptic drugs induce or inhibit CYP enzymes. Phenytoin, carbamazepine, and phenobarbital are potent inducers.
Antiepileptics: Drug-Drug Interactions
Phenytoin, carbamazepine, topiramate, and clobazam can reduce effectiveness of hormonal contraceptives by increasing metabolism.
AEDs and Contraceptives
Inhibit breakdown of acetylcholine, enhancing cholinergic transmission. Used for mild to moderate Alzheimer’s disease.
Acetylcholinesterase Inhibitors: Role in AD
Donepezil (daily dosing), rivastigmine (oral and patch, used in PD-related dementia), galantamine (dual MOA).
AChE Inhibitors: Common Agents
GI effects (nausea, diarrhea), bradycardia, syncope, muscle cramps. Risk of falls due to vagotonic effects.
AChE Inhibitors: Adverse Effects
Anticholinergics reduce efficacy; beta-blockers increase bradycardia risk. Monitor for GI effects and syncope.
AChE Inhibitors: Interactions and Monitoring
Memantine blocks NMDA receptors to prevent excitotoxicity from excess calcium influx. Used in moderate to severe AD.
NMDA Receptor Antagonist: Role in AD
Generally well tolerated. May cause agitation, confusion, dizziness, and headache, which may be difficult to differentiate from AD symptoms.
Memantine: Adverse Effects
Topiramate and divalproex are effective options. Start low and titrate to avoid side effects.
AEDs in Migraine Prevention
Cognitive dysfunction, paresthesia, fatigue, weight loss, kidney stones, and glaucoma.
Topiramate: Adverse Effects
Hepatotoxicity, pancreatitis, teratogenicity (neural tube defects). Common side effects include nausea, tremor, weight gain.
Valproate: Adverse Effects and Black Box Warnings
Avoid valproate due to teratogenic risk. Counsel on contraception and folic acid supplementation.
Migraine AED Use in Reproductive-Age Patients
Topiramate blocks sodium channels and enhances GABA. Divalproex increases GABA availability and suppresses neuronal firing.
Topiramate and Divalproex: MOA in Migraine
May reduce frequency and intensity of attacks by up to 50–70%. Benefits begin within weeks; maximum effect may take months.
Migraine Prevention: Efficacy and Onset
Includes weight changes, fatigue, cognitive changes, and teratogenicity. Monitor patients closely for tolerability.
Migraine Prevention: Adverse Effects
