DRUG INTERACTIONS
Drug Interactions
Interactions Common for Both Benazepril and Hydrochlorothiazide
Potassium Supplements and Potassium-Sparing Diuretics: Concomitant use with Lotensin HCT may effect potassium levels. Monitor potassium periodically.
Lithium: Renal clearance of lithium is reduced by thiazides and increase the risk of lithium toxicity. Increased serum lithium levels and symptoms of lithium toxicity have been reported in patients receiving ACE inhibitors during therapy with lithium. Monitor lithium levels when used concomitantly with Lotensin HCT.
Dual Blockade of the Renin-Angiotensin System (RAS): Dual blockade of the RAS with angiotensin receptor blockers, ACE inhibitors, or aliskiren is associated with increased risks of hypotension, hyperkalemia, and changes in renal function (including acute renal failure) compared to monotherapy. Closely monitor blood pressure, renal function and electrolytes in patients on Lotensin HCT and other agents that block the RAS.
Do not co-administer aliskiren with Lotensin HCT in patients with diabetes. Avoid use of aliskiren with Lotensin HCT in patients with renal impairment (GFR <60 ml/min).
NSAIDs and Cox-2 selective agents: In patients who are elderly, volume-depleted (including those on diuretic therapy), or with compromised renal function, co-administration of NSAIDs, including selective COX-2 inhibitors, with ACE inhibitors, including benazepril, may result in deterioration of renal function, including possible acute renal failure. These effects are usually reversible. Monitor renal function periodically in patients receiving benazepril and NSAID therapy.
The antihypertensive effect of benazepril and hydrochlorothiazide may be attenuated by NSAIDs.
Benazepril
Benazepril has been used concomitantly with beta-adrenergic-blocking agents, calcium-blocking agents, cimetidine, diuretics, digoxin, hydralazine, and naproxen without evidence of clinically important adverse interactions. Other ACE inhibitors have had less than additive effects with beta-adrenergic blockers, presumably because drugs of both classes lower blood pressure by inhibiting parts of the renin-angiotensin system.
Interaction studies with warfarin and acenocoumarol have failed to identify any clinically important effects of benazepril on the serum concentrations or clinical effects of these anticoagulants.
Gold: Nitritoid reactions (symptoms include facial flushing, nausea, vomiting and hypotension) have been reported rarely in patients on therapy with injectable gold (sodium aurothiomalate) and concomitant ACE inhibitor therapy.
Hydrochlorothiazide
Ion exchange resins: Stagger the dosage of hydrochlorothiazide and ion exchange resins such that hydrochlorothiazide is administered at least 4 hours before or 4-6 hours after the administration of resins. Single doses of either cholestyramine or colestipol resins bind the hydrochlorothiazide and reduce its absorption from the gastrointestinal tract by up to 85% and 43%, respectively.
Digitalis glycosides: Thiazide-induced hypokalemia or hypomagnesemia may predispose the patients to digoxin toxicity
Skeletal muscle relaxants: Possible increased responsiveness to muscle relaxants such as curare derivatives.
Antidiabetic agents: Dosage adjustment of antidiabetic drug may be required.
Antineoplastic agents (e.g., cyclophosphamide, methotrexate): Concomitant use of thiazide diuretics may reduce renal excretion of cytotoxic agents and enhance their myelosuppressive effects.
Drugs that alter gastrointestinal motility: The bioavailability of thiazide-type diuretics may be increased by anticholinergic agents (e.g., atropine, biperiden), apparently due to a decrease in gastrointestinal motility and the stomach emptying rate. Conversely, pro-kinetic drugs may decrease the bioavailability of thiazide diuretics.
Cyclosporin: Concomitant treatment with diuretics may increase the risk of hyperuricaemia and gout-type complications.
Alcohol, barbiturates or narcotics: Concomitant administration of thiazide diuretics with alcohol, barbiturates, or narcotics may potentiate orthostatic hypotension.
Pressor amines: Hydrochlorothiazide may reduce the response to pressor amines such as noradrenaline but the clinical significance of this effect is not sufficient to preclude their use.
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