Drug Interaction Report

MONITOR: Nonsteroidal anti-inflammatory drugs (NSAIDs) may attenuate the antihypertensive effect of beta-blockers. The proposed mechanism is NSAID-induced inhibition of renal prostaglandin synthesis, which results in unopposed pressor activity producing hypertension. In addition, NSAIDs can cause fluid retention, which also affects blood pressure. Indomethacin and piroxicam have been reported to have greater attenuating effects than other NSAIDs, and indomethacin effects may be significant in patients with eclampsia.

MANAGEMENT: Patients receiving a beta-blocker who require prolonged (greater than 1 week) concomitant therapy with an NSAID should have blood pressure monitored more closely following initiation, discontinuation, or change of dosage of the NSAID. The interaction is not expected to occur with low doses (e.g., low-dose aspirin) or intermittent short-term administration of NSAIDs.

MONITOR: Many psychotherapeutic and CNS-active agents (e.g., anxiolytics, sedatives, hypnotics, antidepressants, antipsychotics, opioids, alcohol, muscle relaxants) exhibit hypotensive effects, especially during initiation of therapy and dose escalation. Coadministration with antihypertensives and other hypotensive agents, in particular vasodilators and alpha-blockers, may result in additive effects on blood pressure and orthostasis.

MANAGEMENT: Caution and close monitoring for development of hypotension is advised during coadministration of these agents. Some authorities recommend avoiding alcohol in patients receiving vasodilating antihypertensive drugs. Patients should be advised to avoid rising abruptly from a sitting or recumbent position and to notify their physician if they experience dizziness, lightheadedness, syncope, orthostasis, or tachycardia. Patients should also avoid driving or operating hazardous machinery until they know how the medications affect them.