Pharmacology Mnemonics - Flash Cards

Name: Lamotrigine (Lamictal)

Class: Antiepileptic Agent (Complex-Partial)

Mechanism: Inhib. release of glutamate. Inhib Na⁺-med. sustained firing.

Absorption: Oral ® 100% bioavailability.

Dist.: Protein binding 55%

Metabolism.: Primarily hepatic Metabolism.

Excretion, t½: Long t½.

Toxicity/S.E.s: Most common—somnolence, dizziness, headache, blurred vision, diplopia, ataxia, n/v. Less common—rash (mild-severe), esp. w/concurrent use of valproic acid. Drug interactions—¯ w/phenytoin, carbamazepine; ­ w/valproic acid. \ When administering w/valproic acid, start w/low dose (25 mg/d), then titrate up.

Utility: Adj. therapy of partial seizures, including secondarily generalized. Possible alt. for generalized absence.

Special Features: Long t½, low toxicity profile, defined therapeutic range, different Mechanism of action. But Metabolism. affected by concurrent antiepileptic therapy, and experience w/monotherapy is limited.

Name: Gabapentin (Neurontin)

Class: Antiepileptic Agent (Complex-Partial)

Mechanism: Unknown. Transp. into brain. Binds to unique specific receptor. Appears to inhib Na⁺-med. sustained firing. ­ brain GABA levels.

Absorption: Oral ® 60% bioavailability. Actively absorbed by l-amino acid transport system. Dose-dependent decrease in absorption at doses > 600 mg.

Dist.: <10%>

Metabolism.:

Excret. t½: Almost 100% excret. unchanged by kidney (µ to creatinine clearance). 5-7 hr (adults).

Toxicity/S.E.s: Somnolence, dizziness, ataxia, fatigue, nystagmus, headache, tremor, diplopia, n/v. No drug interactions.

Utility: Adj. therapy of partial seizures, including secondarily generalized. Management of neuropathic pain (off-label).

Special Features: Cleanest (regarding drug interactions) antiepileptic drug. Low toxicity profile. However, there is limited clinical experience w/it against other seizure types, limited experience w/monotherapy, and it has a short t½.

Name: Felbamate (Felbatol)

Class: Antiepileptic Agent (Complex-Partial)

Mechanism: Multiple. Blocks voltage-dependent Na⁺ channels ® inhib. of sustained high-freq repetitive neuron firing. Modulates strychnine-insens. glycine receptor. May enhance GABAergic neurotransmission.

Absorption: Oral ® 100% bioavail.

Dist.: 22-25% protein binding

Metabolism.: 50% hepatic, 50% renal. Excretion, t½: 20-23 hr (adults)

Toxicity/S.E.s: Most serious—aplastic anemia, acute hepatic failure. Patients & physicians both required by FDA to sign info/consent form. Most common—anorexia, n/v, insomnia, headache. Drug interactions—¯ w/phenytoin, carbamazepine.

Utility: Not DOC for anything. Monotherapy or adj. therapy of partial seizures in patients ³ 14 y.o. Adj. therapy of partial & gen. seizures assoc. w/Lennox-Gastaut synd.

Special Features: Broad-spectrum anticonvulsant. Effective as add-on & monotherapy. But multiple drug interactions, signif. S.E.s w/initial dosing, & increased risk of aplastic anemia & acute hepatic failure diminish its charm.

Name: Clonazepam (Clonopin)

Class: Benzodiazepine (Antiepileptic: Absence)

Mechanism: Acts on BZD receptors closely coupled to GABA_A receptors ® enhancement of GABA inhib. action via ­ freq. of Cl^- channel opening.

Absorption:

Dist.: Metabolism.: Excretion, t½:

Toxicity/S.E.s: All dose-related. Acute—excessive depression of CNS fxns (drowsiness, sleep, confusion, disorientation, ataxia, slurred speech, nystagmus, mild amnesia, dementia). May also cause aggression, hyperactivity, delirium, insomnia. Large doses or mixture w/depressants (e.g., EtOH) may cause resp. depression, coma, hallucinations, nightmares, confusion. Chronic—impaired thinking/memory, weight gain/loss. Habituation & physical dependence ® w/drawal syndrome. Abrupt discontinuation ® risk for convulsion. Metabolism. ¯ in elderly and by cimetidine. Overdose ® serious resp. depression (rarely fatal w/support). Development of tolerance.

Utility: Alt. to ethosuximide and valproate for uncomp. absence. Alt. to valproate for atypical absence. Limited use due to development of tolerance.

Special Features:

Name: Ethosuximide (Zarontin)

Class: Antiepileptic Agent (Absence)

Mechanism: Reduces T-channel Ca²⁺ currents ® ­ seizure threshold.

Absorption:

Dist.: 0% protein binding.

Metabolism.:

Excretion, t½: 20-60 hr (adults & kids)

Toxicity/S.E.s: Dose-related—anorexia, nausea, fatigue, headache. Non-dose-rel.—blood-dyscrasia, SLE-like rxn, hepatitis.

Utility: A DOC for uncomplicated absence.

Special Features: