Normetec Drug Interactions

Amlodipine/Olmesartan Medoxomil (Normetec): The blood pressure lowering effect of Amlodipine/Olmesartan Medoxomil (Normetec) can be increased by concomitant use of other antihypertensive medicinal products (e.g. alpha blockers, diuretics).
No drug interaction studies have been conducted with Amlodipine/Olmesartan Medoxomil (Normetec) and other drugs; although, studies have been conducted with the individual olmesartan medoxomil and amlodipine components of Amlodipine/Olmesartan Medoxomil (Normetec), as described as follows.
Olmesartan medoxomil: Use with Lithium: Increases in serum lithium concentrations and lithium toxicity have been reported during concomitant administration of lithium with angiotensin II receptor antagonists, including olmesartan. Monitor serum lithium levels during concomitant use.
Dual Blockade of the Renin-Angiotensin System (RAS): Dual blockade of the RAS with angiotensin receptor antagonists, ACE inhibitors or aliskiren is associated with increased risks of hypotension, hyperkalemia and changes in renal function (including acute renal failure) compared to monotherapy. Monitor blood pressure, renal function and electrolytes in patients on olmesartan and other agents that affect the RAS.
Use with Aliskiren: Do not co-administer aliskiren with olmesartan medoxomil in patients with diabetes (see Pharmacology under Actions) because dual use is associated with increased risks of hypotension, hyperkalemia, and changes in renal function (including acute renal failure) compared to monotherapy.
Use with Non-steroidal Anti-inflammatory Drugs (NSAIDs): NSAIDs and angiotensin receptor blockers (ARBs) may act synergistically by decreasing glomerular filtration. The concomitant use of NSAIDs and ARBs may increase the risk of worsening renal function.
Additionally, the antihypertensive effect of ARBs, including olmesartan, may be attenuated by NSAIDs, including selective cox2 inhibitors.
Use with Colesevelam Hydrochloride: Concurrent administration of bile acid sequestering agent colesevelam hydrochloride reduces the systemic exposure and peak plasma concentration of olmesartan. Administration of olmesartan at least 4 hours prior to colesevelam hydrochloride decreased the drug interaction effect (see Pharmacology under Actions).
Amlodipine (as Besilate): Concomitant Use Requiring Caution: CYP3A4 inhibitors (e.g. ketoconazole, itraconazole, ritonavir): A study in elderly patients showed that diltiazem inhibits the metabolism of amlodipine, probably via CYP3A4, since plasma concentrations of amlodipine increased by approximately 50% and its effect was therefore increased. The possibility that more potent CYP3A4 inhibitors (e.g. ketoconazole, itraconazole, ritonavir) may increase the plasma concentration of amlodipine to a greater extent than diltiazem cannot be excluded.
CYP3A4 inducers (e.g. anticonvulsants [such as carbamazepine, phenobarbital, phenytoin, fosphenytoin, primidone], rifampicin, Hypericum perforatum): Concomitant administration of CYP3A4 may decrease the plasma concentration of amlodipine. Clinical monitoring is indicated, with possible adjustment of amlodipine dosage during treatment with the CYP3A4 inducer and after its withdrawal.
Simvastatin: Co-administration of multiple doses of 10 mg of amlodipine with 80 mg simvastatin resulted in a 77% increase in exposure to simvastatin compared to simvastatin alone. Limit the dose of simvastatin to 20 mg daily in patients on amlodipine.
Tacrolimus: The co-administration of amlodipine with tacrolimus may increase exposure of tacrolimus. Because Amlodipine/Olmesartan Medoxomil (Normetec) contains amlodipine, monitor tacrolimus blood levels during concomitant use.
Cyclosporine: In a prospective study in renal transplant patients, an average 40% increase in trough cyclosporine levels was observed in the presence of amlodipine. The co-administration of amlodipine with cyclosporine may increase exposure to cyclosporine. Because Amlodipine/Olmesartan Medoxomil (Normetec) contains amlodipine, monitor trough cyclosporine levels during concomitant use.