For an inpatient soon after coronary bypass surgery, do not give a routine sleeping pill without the cardiac-surgery team reviewing them first. Insomnia can signal pain, low oxygen, fluid overload, arrhythmia, medication effects, alcohol/benzodiazepine withdrawal, or delirium.

Seek immediate review rather than a sleep medication if the patient is newly confused, severely restless, hallucinating, short of breath, has chest pain, oxygen desaturation, low blood pressure, fever, or a new irregular heartbeat.

5 mg melatonin has been used in studies of adults after cardiac surgery, including for sleep and delirium prevention. It is generally less likely than benzodiazepines or zolpidem to suppress breathing or cause delirium. However, it should still be given only if the inpatient cardiac-surgery team approves and orders it.

Before giving it, the team should check for:

For a recently bypassed patient, 5 mg may be reasonable if they are stable, alert, breathing well, and the prescribing team agrees, but do not self-administer a home supply while admitted. The better approach is to ask the nurse or resident: “Can you assess the cause of the insomnia and prescribe melatonin if appropriate?”

Evidence in cardiac-surgery populations includes regimens using 3 mg or 5 mg, but results are not definitive and the exact regimen should follow the hospital protocol. A cardiac-surgery meta-analysis found a possible reduction in postoperative delirium, although evidence quality was low.