Nifedipine
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Nifedipine
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| Systematic (IUPAC) name | |
| dimethyl2,6-dimethyl-4-(2-nitrophenyl)- 1,4-dihydropyridine-3,5-dicarboxylate | |
| Identifiers | |
| CAS number | |
| ATC code | C08 |
| PubChem | |
| DrugBank | |
| Chemical data | |
| Formula | C17H18N2O6 |
| Mol. mass | 346.335 g/mol |
| Physical data | |
| Melt. point | 173 °C (343 °F) |
| Pharmacokinetic data | |
| Bioavailability | 45-56% |
| Protein binding | 92-98% |
| Metabolism | Gastrointestinal, Hepatic |
| Half life | 2 hours |
| Excretion | Renal: >50%, Biliary: 5-15% |
| Therapeutic considerations | |
| Pregnancy cat. |
C: (USA) |
| Legal status | |
| Routes | Oral |
Nifedipine (brand name Adalat and Procardia) is a dihydropyridine calcium channel blocker. Its main uses are in angina pectoris (especially Prinzmetal's angina) and hypertension, although a large number of other uses have recently been found for this agent, such as Raynaud's phenomenon, premature labor, and painful spasms of the esophagus in cancer and tetanus patients. It is also commonly used for the small subset of pulmonary hypertension patients whose symptoms respond to calcium channel blockers.
Nifedipine rapidly lowers the blood pressure, and patients are commonly warned they may feel dizzy or faint after taking the first few doses. Tachycardia (fast heart rate) may occur as a reaction. These problems are much less frequent in the sustained-release preparations of nifedipine (such as Adalat OROS).
Extended release formulations of nifedipine should be taken on an empty stomach, and patients are warned not to consume anything containing grapefruit or grapefruit juice, as it lowers CYP3A4 activity (the enzyme that digests nifedipine) and may lead to increased levels of nifedipine or other medications that are metabolised by CYP3A4 in the blood.
[edit] Off-label use of Nifedipine
While the use of the sustained-release form Nifedipine has a documented record of safety, some doctors continue to use it sublingually for hypertensive crises (emergency situations where bringing down the blood pressure is of critical importance to avoid organ damage). The sublingual use of Nifedipine has not been approved by the FDA, and the Cardiorenal Advisory Committee of the FDA has concluded that sublingual administration of nifedipine should be abandoned because it is neither safe nor efficacious.(Varon, 2003.)
Documented cases indicate that sublingual administration of nifedipine has caused:
- death
- stroke
- acute myocardial infarction (tissue death of the heart muscle mass)
- cerebrovascular ischemia (lack of blood flow to the brain)
- severe hypotension (very low blood pressure)
- conduction disturbances
- fetal distress
Nifedipine has also been shown to be effective as a wound healing agent when used topically. Numerous studies have shown conclusively that when applied in concentrations as low as 0.3%, nifedipine is effective for treating chronic anal fissures(Erzi,Dis Colon Rectum. 2003 Jun;46(6):805-8), with few side effects of alternative agents.
[edit] References
- Nifedipine - rxlist.com
- MedlinePlus DrugInfo medmaster-a684028
- Varon, Joseph and Paul E Marik (2003) Clinical review: The management of hypertensive crises Crit Care; 7(5): 374–384.
- Grossman E, Messerli FH, Grodzicki T, Kowey P. (1996) Should a moratorium be placed on sublingual nifedipine capsules given for hypertensive emergencies and pseudoemergencies? JAMA Oct 23-30;276(16):1328-31.
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| Dihydropyridines | Amlodipine, Felodipine, Isradipine, Lacidipine, Lercanidipine, Nicardipine, Nifedipine, Nimodipine, Nisoldipine |
| Phenylalkylamines | Verapamil |
| Benzothiazepines | Diltiazem |
