Pharmacology and Toxicology in Neurocritical Care
Core pharmacology
Know the neurocritical drugs and their pitfalls: osmotic agents (mannitol vs hypertonic saline), antiseizure medications, sedatives (propofol, midazolam, dexmedetomidine), vasopressors, and anticoagulants/reversal agents. Understand pharmacokinetics in critically ill patients (altered volume of distribution, organ dysfunction) and drug interactions.
Toxicology
Recognize toxidromes relevant to neurocritical care: opioid (miosis, respiratory depression), sympathomimetic (agitation, hypertension, hyperthermia), anticholinergic, and serotonin syndrome. Know antidotes (naloxone, flumazenil caveats, sodium bicarbonate for TCA, lipid emulsion for local anesthetics). Recognize that alcohol withdrawal and sedative withdrawal can cause seizures and delirium.
Traps
- Using flumazenil in mixed overdose or seizure-prone patients (risk of seizures).
- Forgetting that mannitol can cause hypovolemia and hypernatremia; monitor osmolality.
- Missing serotonin syndrome vs neuroleptic malignant syndrome (clonus/hyperreflexia vs rigidity).
- Overlooking drug-induced seizures or encephalopathy.
Rule of thumb
Identify the toxidrome, stabilize ABCs, and use antidotes when indicated - but never delay supportive care for a specific antidote.
Worked example
A patient with agitation, hyperthermia, clonus, and recent SSRI plus tramadol: serotonin syndrome - stop serotonergic agents, provide supportive care, and consider cyproheptadine in severe cases.