Pharmacotherapy of Neurological and Psychiatric Disorders
Core concepts
Master the pharmacology of antidepressants (SSRIs, SNRIs, TCAs, MAOIs), antipsychotics (typical vs atypical), mood stabilisers (lithium, valproate, lamotrigine), antiepileptics and drugs for Parkinson disease. Know mechanisms, key adverse effects and monitoring. SSRIs are first-line for depression and anxiety; TCAs are dangerous in overdose (cardiotoxicity, anticholinergic effects). Atypical antipsychotics carry metabolic risk (weight gain, hyperglycaemia, dyslipidaemia) requiring baseline and periodic monitoring. Lithium has a narrow therapeutic index (roughly 0.6–1.0 mmol/L maintenance) and requires renal, thyroid and calcium monitoring.
Traps in questions
Serotonin syndrome versus neuroleptic malignant syndrome is a classic confusion: serotonin syndrome has clonus and hyperreflexia, NMS has rigidity and bradyreflexia. Another trap is stopping antiepileptics abruptly (seizure rebound). Watch for lamotrigine titration too fast (Stevens-Johnson syndrome) and for valproate in pregnancy (teratogenic). Questions may also test that antipsychotics can prolong QT.
Worked rule of thumb
For lithium, remember "levels, kidneys, thyroid, calcium": check serum level 12 hours post-dose, monitor creatinine, TSH and calcium every 6–12 months. For serotonin syndrome, the triad is mental status change, autonomic instability, neuromuscular hyperactivity - clonus is the discriminator.