Indications/Uses
Dosage/Direction for Use
Overdosage
Amlodipine: Gross overdosage could result in excessive peripheral vasodilation and possibly reflex tachycardia. Marked and probably prolonged systemic hypotension up to and including shock with fatal outcome have been reported.
Administration
Contraindications
Warnings
Special Precautions
Amlodipine should be used with caution in patients with hypotension, in patients whose cardiac reserve is poor, and in those with heart failure has been noted. It should not be used in cardiogenic shock, in patient who have recently suffered a myocardial infarction, or in acute unstable angina. It should not be used to treat an angina attack in chronic stable angina. In patients with severe aortic stenosis it may increase the risk of developing heart failure. Sudden withdrawal might be associated with an exacerbation of angina. The dose may need to be reduced in patients with hepatic impairment. It should be discontinued in patients who experience ischaemic pain following its administration.
Use In Pregnancy & Lactation
Lactation: It is not known whether Losartan or Amlodipine is excreted in human milk. In the absence of this information, it is recommended that nursing may be discontinued while combination is administered.
Adverse Reactions
Overdose may be associated with bradycardia and hypotension.
Drug Interactions
Fluconazole: Fluconazole, an inhibitor of cytochrome P4502C9, decreased active metabolite concentration and increased Losartan concentration.
Agents that increases Serum Potassium: As with other drugs that block angiotensin II or its effects, concomitant use of potassium-sparing diuretics, potassium supplements or salt substitutes containing potassium may lead to increase in serum potassium.
Lithium: Losartan reduces lithium excretion; hence, serum lithium levels should be monitored carefully if lithium salts are to be co-administered with this combination.
Non-Steroidal Anti-Inflammatory Agents (NSAIDs) including Selective Cyclooxygenase-2 inhibitors: In some patients with compromised renal function who are being treated with NSAIDs, including those that selectively inhibit cyclooxygenase-2 inhibitors (COX-2 inhibitors), the co-administration of Losartan may result in a further deterioration of renal function. These effects are reversible. Reports suggest that NSAIDs, including selective COX-2 inhibitors may diminish the antihypertensive effect of Losartan. This interaction should be given consideration in patients taking NSAIDs, including selective COX-2 inhibitors, concomitantly with this combination of Losartan and Amlodipine.
Storage
Action
Amlodipine: Amlodipine inhibits the transmembrane influx of calcium ions into vascular smooth muscle and cardiac muscle. Experimental data suggest that Amlodipine binds to both dihydropyridine and non-dihydropyridine binding sites. The contractile processes of cardiac muscle and vascular smooth muscle are dependent upon the movement of extracellular calcium ions into these cells through specific ion channels. Amlodipine inhibits calcium ion influx across cell membranes selectively, with a greater effect on vascular smooth muscle cells than on cardiac muscle cells. Amlodipine is a peripheral arterial vasodilator that acts directly on vascular smooth muscle to cause a reduction in peripheral vascular resistance and reduction in blood pressure.
Pharmacokinetics: Losartan is readily absorbed from the gastrointestinal tract following oral administration, with an oral bioavailability of about 33%. It undergoes first-pass metabolism to form an active carboxylic acid metabolite E-3174 (EXP-3174), which has greater pharmacological activity than Losartan, and some inactive metabolites. Metabolism is primarily by cytochrome P450 isoenzymes CYP2C9 and CYP3A4. Peak plasma concentrations of Losartan and E-3174 occur about 1 hour and 3 to 4 hours, respectively after an oral dose. Both Losartan and E-3174 are more than 98% bound to plasma proteins. Losartan is excreted in the urine, and in the faeces via bile, as unchanged drug and metabolites. Following oral dosing about 35% of the dose if excreted in the urine and about 60% in the faeces. The terminal elimination half-lives of Losartan and E-3174 are about 1.5 to 2.5 hours and 3 to 9 hours, respectively.
Amlodipine is well absorbed following oral administration with peak blood concentrations occurring after 6 to 12 hours. The bioavailability is about 60 to 65%. Amlodipine is reported to be about 97.5% bound to plasma proteins. It has a prolonged terminal elimination half-life of 35 to 50 hours and steady-state plasma concentrations are not achieved until 7 to 8 days of administration. Amlodipine is extensively metabolized in the liver; metabolites are mostly excreted in urine together with less than 10% of dose as unchanged drug.
MedsGo Class
Features
- Amlodipine
- Losartan Potassium