Drug interactions between Inderide and Marax DF

propranolol ↔ theophylline

Applies to:Inderide (hydrochlorothiazide/propranolol) and Marax DF (ephedrine/hydroxyzine/theophylline)

GENERALLY AVOID: The pharmacologic effects of theophyllines and beta-blockers are opposite. Nonselective and high doses of cardioselective beta-blockers may cause severe or fatal bronchospasm by opposing theophylline-induced bronchodilation. Ophthalmic beta-blockers undergo significant systemic absorption and may also interact. In addition, propranolol and other beta-blockers may reduce the CYP450 hepatic metabolism of theophylline, and serum theophylline levels may be increased.

MANAGEMENT: Oral and ophthalmic nonselective beta-blockers (e.g., carteolol, carvedilol, levobunolol, metipranolol, nadolol, oxprenolol, penbutolol, pindolol, propranolol, sotalol, and timolol) are considered contraindicated in patients with bronchospastic diseases. Cardioselective beta-blockers should generally be avoided, or used with extreme caution if no other alternatives are available and the benefits outweigh the risks of potentially severe bronchospasm. If patients do receive this combination, they should be closely monitored for increased serum theophylline levels but decreased bronchodilatory effectiveness.

propranolol ↔ ephedrine

Applies to:Inderide (hydrochlorothiazide/propranolol) and Marax DF (ephedrine/hydroxyzine/theophylline)

MONITOR: Beta-blockers may antagonize the cardiostimulatory effects of ephedrine by blocking beta-1 adrenergic receptors in the heart. Parenteral ephedrine may be less effective in the treatment of shock and hypotension if the patient is receiving, or has recently received, a beta-blocking drug. In addition, peripheral vascular resistance may increase due to unopposed alpha-adrenergic effect of ephedrine in the presence of beta-blockade. Theoretically, the interaction may also occur with beta-blocker ophthalmic preparations, since they may be systemically absorbed and can produce clinically significant systemic effects even at low or undetectable plasma levels.

MANAGEMENT: Clinicians should be alert to the potential for diminished cardiac response when parenteral ephedrine is used in patients treated with beta-blockers, including ophthalmic formulations.

GENERALLY AVOID: Noncardioselective beta-blockers can antagonize the bronchodilating effects of ephedrine by blocking beta-2 adrenergic receptors in smooth muscles of the bronchial tree. The interaction is less likely to occur with cardioselective beta-blockers, which generally have little effect on beta-2 adrenergic receptors at therapeutic dosages. However, cardioselectivity is not absolute and may be lost with larger doses.

MANAGEMENT: Noncardioselective beta-blockers, including ophthalmic formulations, should generally be avoided in patients using ephedrine-containing preparations for bronchospastic diseases. If beta-blocker therapy is necessary, an agent with beta-1 selectivity (e.g., atenolol, metoprolol, betaxolol) is considered safer. However, caution is advised, especially with higher dosages of the beta-blocker.

propranolol ↔ hydroxyzine

Applies to:Inderide (hydrochlorothiazide/propranolol) and Marax DF (ephedrine/hydroxyzine/theophylline)

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 antihypertensive agents, in particular vasodilators and alpha-blockers, may result in additive effects on blood pressure and orthostasis.

MANAGEMENT: Caution is advised during coadministration of these agents. Close monitoring for development of hypotension is recommended. 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.

hydrochlorothiazide ↔ hydroxyzine

Applies to:Inderide (hydrochlorothiazide/propranolol) and Marax DF (ephedrine/hydroxyzine/theophylline)

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 antihypertensive agents, in particular vasodilators and alpha-blockers, may result in additive effects on blood pressure and orthostasis.

MANAGEMENT: Caution is advised during coadministration of these agents. Close monitoring for development of hypotension is recommended. 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.