How should chronic psychiatric medications be managed before surgery?

Perioperative Management of Psychiatric Medications

Continue all chronic psychiatric medications through the perioperative period, with the single exception of lithium, which should be stopped 72 hours before major surgery. 1, 2

General Principle

The overriding concern is preventing psychiatric relapse, withdrawal syndromes, and postoperative delirium—all of which significantly increase morbidity and mortality. The risk of stopping psychiatric medications almost always exceeds the risk of continuing them perioperatively. 2, 3

Specific Medication Classes

Antidepressants (SSRIs, SNRIs, TCAs, Atypical)

• Continue perioperatively 1, 2, 3
• Stopping risks discontinuation syndrome and psychiatric decompensation
• Be vigilant for serotonin syndrome when combining with meperidine, tramadol, or linezolid
• TCAs may potentiate sympathomimetics and anticholinergics—use lower doses of vasopressors initially

MAO Inhibitors

• Continue in most cases with careful anesthetic planning 2, 3
• Avoid meperidine absolutely (can cause fatal serotonin syndrome)
• Use direct-acting vasopressors (phenylephrine, vasopressin) rather than indirect agents
• If discontinuation is deemed necessary, requires 2 weeks washout—but this significantly increases psychiatric relapse risk

Antipsychotics

• Continue perioperatively 1, 2, 4
• Continuation actually reduces postoperative delirium in schizophrenic patients 4
• Monitor for QT prolongation, hypotension, and neuroleptic malignant syndrome
• Maintain adequate hydration and temperature control

Mood Stabilizers

Lithium: Stop 72 hours before major surgery 1, 3

• Narrow therapeutic window with significant toxicity risk
• Surgery-related fluid shifts and NSAIDs dramatically increase lithium levels
• Resume postoperatively once fluid status stable and renal function normal

Anticonvulsants (valproate, carbamazepine, lamotrigine): Continue 1, 2

• Stopping risks seizures perioperatively
• May interact with muscle relaxants—monitor neuromuscular blockade carefully
• Difficult to maintain therapeutic levels if NPO—consider IV formulations when available

Anxiolytics (Benzodiazepines)

• Continue perioperatively 1, 2
• Abrupt discontinuation causes withdrawal seizures and severe anxiety
• May require higher anesthetic doses due to cross-tolerance
• Continue scheduled doses; hold PRN doses only

Stimulants (ADHD medications)

• Hold on day of surgery 2, 3
• Risk of perioperative hypertension, tachycardia, and arrhythmias
• Can potentiate vasopressor response
• Resume postoperatively once hemodynamically stable
• For patients at high risk of severe ADHD symptoms, individualize with psychiatry consultation

Critical Pitfalls to Avoid

1. Do not stop medications "just to be safe"—psychiatric relapse and withdrawal are more dangerous than continuing therapy
2. Never combine meperidine with any serotonergic medication (SSRIs, SNRIs, MAOIs, TCAs)
3. Do not assume benzodiazepine tolerance means inadequate anesthesia—use objective monitoring
4. Remember lithium is the exception—it must be stopped for major surgery
5. Coordinate with psychiatry preoperatively for complex cases, not as a crisis intervention postoperatively

Anesthetic Considerations

• Expect potentially increased anesthetic requirements with chronic benzodiazepines
• Use regional anesthesia when possible to minimize systemic drug interactions
• Have vasopressin or phenylephrine available as first-line vasopressors (especially with MAOIs)
• Monitor temperature closely (risk of neuroleptic malignant syndrome, serotonin syndrome)
• Ensure adequate postoperative pain control—uncontrolled pain worsens psychiatric symptoms