Clonidine and Quetiapine interaction
Clonidine and Quetiapine: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Clonidine (QLONILIK) label · effective 2026-08-12
Avoid use with other central nervous system (CNS) depressants ( 5.3 )
Avoid use with other central nervous system (CNS) depressants, as this combination may cause excessive drowsiness or sedation [see Drug Interactions (7) ].
Intervention Avoid concomitant use of CNS depressants with QLONILIK.
Intervention Monitor blood pressure and heart rate, and adjust dosage of QLONILIK accordingly in patients treated concomitantly with antihypertensives CNS depressants Clinical Implication Concomitant use of CNS depressants with clonidine potentiates the sedating effects [see Warnings and Precautions (5.3) ].
Concomitant use of CNS depressants with clonidine potentiates the sedating effects.
From the Quetiapine (SEROQUEL XR) label · effective 2026-04-10
Quetiapine should be used with particular caution in patients with known cardiovascular disease (history of myocardial infarction or ischemic heart disease, heart failure, or conduction abnormalities), cerebrovascular disease, or conditions which would predispose patients to hypotension (dehydration, hypovolemia, and treatment with antihypertensive medications).
Effect of Quetiapine on Other Drugs Because of its potential for inducing hypotension, SEROQUEL XR may enhance the effects of certain antihypertensive agents.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.