"What are calcium channel blockers (CCBs) and how do they work?
Calcium channel blockers are drugs that block the entry of calcium into the muscle cells of the heart and arteries.
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Symptomatic hypotension is possible, particularly in patients with severe aortic stenosis. Because of the gradual onset of action, acute hypotension is unlikely.
Increased Angina or Myocardial Infarction
Patients with Hepatic Failure
Because NORVASC is extensively metabolized by the liver and the plasma elimination half-life (t ½) is 56 hours in patients with impaired hepatic function, titrate slowly when administering NORVASC to patients with severe hepatic impairment.
Carcinogenesis, Mutagenesis, Impairment of Fertility
Rats and mice treated with amlodipine maleate in the diet for up to two years, at concentrations calculated to provide daily dosage levels of 0.5, 1.25, and 2.5 amlodipine mg/kg/day, showed no evidence of a carcinogenic effect of the drug. For the mouse, the highest dose was, on a mg/m² basis, similar to the maximum recommended human dose of 10 mg amlodipine/day.3 For the rat, the highest dose was, on a mg/m² basis, about twice the maximum recommended human dose.3
Mutagenicity studies conducted with amlodipine maleate revealed no drug related effects at either the gene or chromosome level.
There was no effect on the fertility of rats treated orally with amlodipine maleate (males for 64 days and females for 14 days prior to mating) at doses up to 10 mg amlodipine/kg/day (8 times the maximum recommended human dose3 of 10 mg/day on a mg/m² basis).
Use In Specific Populations
Pregnancy Category C
There are no adequate and well-controlled studies in pregnant women. Amlodipine should be used during pregnancy only if the potential benefit justifies the risk to the fetus.
No evidence of teratogenicity or other embryo/fetal toxicity was found when pregnant rats and rabbits were treated orally with amlodipine maleate at doses up to 10 mg amlodipine/kg/day (respectively, 8 times2 and 23 times2 the maximum recommended human dose of 10 mg on a mg/m² basis) during their respective periods of major organogenesis. However, litter size was significantly decreased (by about 50%) and the number of intrauterine deaths was significantly increased (about 5-fold) in rats receiving amlodipine maleate at a dose equivalent to 10 mg amlodipine/kg/day for 14 days before mating and throughout mating and gestation. Amlodipine maleate has been shown to prolong both the gestation period and the duration of labor in rats at this dose.
It is not known whether amlodipine is excreted in human milk. In the absence of this information, it is recommended that nursing be discontinued while NORVASC is administered.
NORVASC (2.5 to 5 mg daily) is effective in lowering blood pressure in patients 6 to 17 years [see Clinical Studies]. Effect of NORVASC on blood pressure in patients less than 6 years of age is not known.
Clinical studies of NORVASC did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy. Elderly patients have decreased clearance of amlodipine with a resulting increase of AUC of approximately 40–60%, and a lower initial dose may be required [see DOSAGE AND ADMINISTRATION].
2 Based on patient weight of 50 kg.
Last reviewed on RxList: 1/22/2013
This monograph has been modified to include the generic and brand name in many instances.
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