RiteMED Clonidine Drug Interactions

CNS depressants (e.g., opiates), other analgesics, barbiturates or other sedatives, anesthetics, or alcohol: Clonidine may be additive with, or may potentiate the action of these drugs.
Drugs that affect the sinus node function or atrioventricular nodal conduction (e.g., guanethidine), beta-blockers (e.g., propranolol), calcium antagonists, cardiac glycosides: Possible additive effects since clonidine may produce bradycardia and atrioventricular block.
Haloperidol (high IV doses): In patients in a state of alcoholic delirium, high IV doses of clonidine may increase the arrhythmogenic potential (QT-prolongation, ventricular fibrillation) of high IV doses of haloperidol. The causal relationship and relevance for antihypertensive treatment have not been established.
Psychotherapeutic agents, tricyclic antidepressants (e.g., imipramine, desipramine): May block the blood pressure lowering effect of clonidine. The increase in blood pressure usually occurs during the second week of tricyclic antidepressant therapy, but occasionally may occur during the first several days of concomitant therapy. Closely monitor blood pressure during the first several weeks of concurrent therapy and increase clonidine dosage to adequately control hypertension if necessary.
Drugs that increase blood pressure or induce sodium and water retention (e.g., Non-steroidal Anti-inflammatory Drugs, NSAIDs): May reduce the therapeutic effect of clonidine.
Drugs with alpha₂-receptor blocking properties (e.g., phentolamine, tolazoline): May abolish the alpha2-receptor mediated effects of clonidine in a dose dependent manner.
Other hypotensive agents: Increase blood pressure lowering effect of clonidine.