Class: Calcium channel blocking agent
- Tablets, controlled-release 5 mg
- Tablets, controlled-release 10 mg
- Capsules 2.5 mg
- Capsules 5 mg
Reduces systemic vascular resistance and BP by inhibiting movement of calcium ions across cell membrane in systemic and coronary vascular smooth muscle and myocardium.
The bioavailability is 15% to 24%. The C max is approximately 1 ng/mL/mg (immediate release); 3 to 4 ng/mL (controlled release). The T max is 1.5 h (immediate release); 7 to 18 h (controlled release). Increased bioavailability up to 25% with food.
95% is protein bound.
Completely metabolized by ring oxidation and ester cleavage primarily via CYP-450 3A4. Metabolites are inactive.
The t 1/2 is approximately 8 h. 60% to 65% is excreted in the urine, 25% to 30 % in the feces.
Special PopulationsRenal Function Impairment
Mild (CrCl 30 to 80 mL/min)
The AUC increases by 45%.Severe (CrCl is less than 10 mL/min, hemodialysis)
The AUC decreases by 20 to 50%.Hepatic Function Impairment
The C max increases by 32% and AUC increases by 52%.Elderly
The AUC and C max increases.
Indications and Usage
Treatment of hypertension.
Dosage and AdministrationAdults
PO 2.5 to 10 mg/day in 2 divided doses (max dose 20 mg/day).
Store in tightly closed container at room temperature. Protect from light.
None well documented.
Laboratory Test Interactions
None well documented.
Peripheral edema; flushing; palpitations; angina; tachycardia; hypotension; syncope; CHF; MI; atrial or ventricular fibrillation.
Dizziness; lightheadedness; headache; fatigue; lethargy; weakness; shakiness; psychiatric disturbances.
Nausea; diarrhea; constipation; abdominal discomfort; cramps; dyspepsia; vomiting.
Urinary frequency; micturition disorders; sexual difficulties.
Shortness of breath; dyspnea; wheezing.
Transient ischemic attack; stroke.
Category C .
Safety and efficacy not established.
Use with caution in patients with CHF.
Hypotension, dizziness, slurred speech, nausea, weakness, drowsiness, confusion.
- Explain that dosage will be tapered slowly before stopping to avoid withdrawal symptoms. Warn patient that sudden discontinuation may cause serious chest pain.
- Tell patient to brush and floss teeth regularly to minimize gum changes (eg, overgrowth of gums).
- Instruct patient to report the following symptoms to health care provider: irregular heart beat, shortness of breath, swelling of hands or feet, pronounced dizziness, constipation, nausea, or hypotension.
- Advise patient that drug may cause dizziness and to use caution while driving or performing other tasks requiring mental alertness.
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