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Absorption
Nifedipine is rapidly and fully absorbed (100%). T max is about 30 min (immediate-release) and 2.5 to 5 h (extended-release). Bioavailability is 84% to 89% (extended-release) and 45% to 75% (immediate-release).
Distribution
Nifedipine protein binding is 92% to 98%.
Metabolism
Nifedipine is metabolized extensively in the liver to inactive metabolites.
Elimination
Nifedipine is eliminated in urine (0.1% unchanged) and in small amounts in feces. The t ½ is about 7 h (extended-release) and 2 h (immediate-release). 60% to 80% excreted in urine and the remainder in feces in metabolized form.
Special Populations
Hepatic Function Impairment
Longer t ½ , higher bioavailability, and reduced protein binding may occur in patients with liver cirrhosis.
Elderly
Mean C max is 36% higher and plasma concentration is 70% greater in elderly patients.
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