MAOIs and Anticonvulsants Pearls Key points for your Board Review

• Lithium toxicity often due to drug interactions (do not give NSAID, ACE inhibitor, diuretics)

• Lithium is renally eliminated; treat toxicity with IV fluids, dialysis if end-stage renal disease patient

• Monoamine oxidase inhibitor (MAOI) has food interactions (tyramine, aged cheeses, red wine) causing hypertensive crisis; and drug interactions (meperidine, sympathomimetics, dextromethorphan, SSRI, lithium) causing serotonin syndrome

• Metal Fume fever = “Monday morning fever” (welder with flu-like symptoms that improve over the week); normal chest x-ray

• Methemoglobinemia = hypoxia unresolved with oxygen; causes = nitrites, aniline dyes, medications; treat with methylene blue

• Mushroom toxicity general rules: immediate vomiting <6hr post-ingestion (better prognosis): symptom onset >6hr post-ingestion (worse prognosis)

• Treat organophosphate toxicity with atropine until secretions dry; also 2-PAM for organophosphates

• Phenytoin = gingival hyperplasia; rapid IV administration can cause hypotension (due to propylene glycol diluent, not from phenytoin itself)

• Salicylate uncouples oxidative phosphorylation = lactic acidosis; presents with mixed primary respiratory alkalosis (tachypnea) + metabolic acidosis

• Salicylate toxicity treatment: activated charcoal, sodium bicarbonate infusion to alkalinize urine (goal serum pH >7.45-7.55 or urine pH>8 to enhance excretion); hemodialysis for renal failure or severe academia

• Chloral hydrate can sensitize myocardium to catecholamines, causing ventricular tachycardia; treat with beta-blocker

• Serotonin Syndrome (exposure to 5HT agent) = altered mental status, rigidity, hyperthermia, clonus, tremor

• Strychnine: similar mechanism as tetanus (myoclonus, opisthotonus, seizure but awake, agitation); found in adulterant in heroin, gopher rodenticide; treat with benzodiazepines and often paralyze/intubate