What are the contraindications of quetiapine?

Absolute Contraindication

• Hypersensitivity to quetiapine or any excipient in the formulation; anaphylactic reactions have been reported

Major Warnings (Relative/Clinical Contraindications)

Elderly Patients with Dementia-Related Psychosis

• Avoid — antipsychotics increase mortality approximately 1.6–1.7x compared to placebo in this population (the rate of death in drug-treated patients was about 4.5%, compared to a rate of about 2.6% in the placebo group)
• However, deaths were primarily cardiovascular or infectious in nature
• Not an approved indication

QTc Prolongation / Cardiac Risk

Avoid quetiapine (or use with extreme caution) in people with the following risk factors:

• Congenital long QT syndrome
• History of cardiac arrhythmia, including bradycardia
• Concomitant use of other QTc-prolonging drugs: Class IA antiarrhythmics (quinidine, procainamide), Class III antiarrhythmics (amiodarone, sotalol), Antimicrobials (macrolides, fluoroquinolones), methadone, TCAs, other antipsychotics
• Hypokalemia or hypomagnesaemia
• Congestive heart failure or cardiac hypertrophy

Drug–Drug Interaction–Related “Functional Contraindications"

• Elderly and those on CYP inhibitors (e.g., fluvoxamine, some SSRIs, clozapine) may have markedly increased serum levels and toxicity; lower doses should be considered
• Quetiapine is sensitive to CYP3A enzyme induction

Suicidality

• Increased risk of suicidal thoughts/behaviour in adolescents and young adults, particularly when used as adjunctive antidepressant therapy; requires close monitoring

Situations Requiring Significant Caution

Note on dementia with Lewy bodies / Parkinson's disease: Quetiapine is sometimes preferred among antipsychotics in this context due to its lower extrapyramidal burden, but the general dementia mortality warning still applies and careful risk-benefit assessment is required.