Do Not Restart at 90 mg
You cannot safely restart citalopram at 90 mg after a 4-5 day gap—this dose exceeds maximum safety limits and poses serious cardiac risks. The patient should be restarted at a maximum of 40 mg daily, which is the FDA-mandated ceiling dose for citalopram due to QT prolongation risks 1, 2, 1, 2, 3.
Critical Safety Issue: The 90 mg Dose is Dangerous
Citalopram causes dose-dependent QT prolongation associated with Torsades de Pointes, ventricular tachycardia, and sudden death at daily doses exceeding 40 mg/day 1. The FDA and EMA have explicitly limited maximum doses due to cardiac safety concerns 2. Your patient has been on a dose more than double the maximum recommended limit—this represents a prescribing error that needs immediate correction, not continuation.
Restart Strategy After 4-5 Days Off
After a 4-5 day gap, citalopram has been substantially cleared from the system (elimination half-life ~35 hours, meaning approximately 3-4 half-lives have passed). The patient will likely experience discontinuation symptoms including:
- Dizziness, fatigue, lethargy, general malaise
- Nausea, vomiting, diarrhea
- Anxiety, irritability, agitation
- Sensory disturbances, paresthesias 1, 4
Restart at 40 mg daily maximum 3. Do not attempt to return to 90 mg—this dose should never have been prescribed. The guidelines explicitly state to start at lower doses and titrate slowly in 10 mg increments at 1-2 week intervals 1.
Why Not Resume at the Previous Dose?
Even if the previous dose were safe (which 90 mg is not), restarting at full dose after several days off carries risks:
- Discontinuation followed by abrupt reinitiation can cause adverse effects including hypertension, adrenergic hyperactivation, and other withdrawal-rebound phenomena 5
- The body has partially adapted to being off the medication—restarting at high doses increases side effect risk
- Citalopram should be titrated gradually to optimize the benefit-to-harm ratio 1
Correct Dosing Going Forward
- Restart at 20-40 mg daily (start lower if patient is elderly, has cardiac risk factors, or experienced significant side effects previously)
- Obtain baseline ECG before restarting, given the history of supratherapeutic dosing and QT prolongation risk 2
- Screen for cardiac risk factors: congenital long QT syndrome, electrolyte abnormalities (hypokalemia, hypomagnesemia), concurrent QT-prolonging medications 1, 3
- Monitor closely for the first 24-48 hours after restart for serotonin syndrome symptoms or adverse effects 1
- Never exceed 40 mg daily—this is an absolute maximum, not a target dose 3
Common Pitfall to Avoid
Do not confuse "the dose the patient was taking" with "the dose the patient should be taking." The fact that someone has been on 90 mg does not make it safe or appropriate. This is a medication error that requires correction, not perpetuation. The evidence is unequivocal that doses above 40 mg carry unacceptable cardiac risks 1, 2, 1, 2, 3.