Nifedipine

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Nifedipine
Nifedipine.svg
Nifedipine-from-xtal-3D-balls.png
Systematic (IUPAC) name
3,5-dimethyl 2,6-dimethyl-4-(2-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate
Clinical data
Trade names Adalat, Procardia, others
AHFS/Drugs.com monograph
MedlinePlus a684028
Pregnancy
category
  • C: (USA)
Routes of
administration		 Oral, Topical
Pharmacokinetic data
Bioavailability 45-56%
Protein binding 92-98%
Metabolism Gastrointestinal, Liver
Biological half-life 2 hours
Excretion Kidneys: >50%, Biliary: 5-15%
Identifiers
CAS Number 21829-25-4 YesY
ATC code C08CA05 (WHO)
PubChem CID: 4485
IUPHAR/BPS 2514
DrugBank DB01115 YesY
ChemSpider 4330 YesY
UNII I9ZF7L6G2L YesY
KEGG D00437 YesY
ChEBI CHEBI:7565 YesY
ChEMBL CHEMBL193 YesY
Chemical data
Formula C17H18N2O6
Molecular mass 346.335 g/mol
  • O=C(OC)\C1=C(\N/C(=C(/C(=O)OC)C1c2ccccc2[N+]([O-])=O)C)C
  • InChI=1S/C17H18N2O6/c1-9-13(16(20)24-3)15(14(10(2)18-9)17(21)25-4)11-7-5-6-8-12(11)19(22)23/h5-8,15,18H,1-4H3 YesY
  • Key:HYIMSNHJOBLJNT-UHFFFAOYSA-N YesY
Physical data
Melting point 173 °C (343 °F)
  (verify)

Nifedipine, sold under the brand names Adalat among others, is a medication used to manage angina, high blood pressure, Raynaud's phenomenon, and premature labor.[1] It is one of the treatments of choice for Prinzmetal angina. It may be used to treat severe high blood pressure in pregnancy. It use in preterm labor may give more time for steroids to improve the babies lungs and to move the mother to a place were more medical care is available before delivery. It is taken by mouth and comes in a fast and slow release formulation.[1]

Common side effects include lightheadedness, headache, feeling tired, leg swelling, cough, and shortness of breath. Serious side effects may include low blood pressure and heart failure.[1] There is tentative evidence that its use in pregnancy is safe; however, it is not recommended during breastfeeding.[2] It is a calcium channel blocker of the dihydropyridine type.[1]

Nifedipine was discovered in 1969 and approved for use in the United States in 1981.[3][1] It is on the WHO Model List of Essential Medicines, the most important medications needed in a basic health system.[4] It is available as a generic medication.[1] The wholesale price for the slow release form is about 1.90 to 3.80 USD per month.[5] In the United States it is about 40 to 60 USD a month depending on the dose.[1]

Medical uses

High blood pressure

The approved uses for are the long-term treatment of hypertension (high blood pressure) and angina pectoris. In hypertension, recent clinical guidelines generally favour diuretics and ACE inhibitors, although calcium channel antagonists, along with thiazide diuretics, are still favoured as primary treatment for patients over 55 and African American patients.[6]

Sublingual nifedipine has previously been used in hypertensive emergencies. It was once frequently prescribed as needed to people taking MAOIs for real or perceived hypertensive crises.[7] This was found to be dangerous, and has been abandoned. Sublingual nifedipine causes blood-pressure lowering through peripheral vasodilation. It can cause an uncontrollable decrease in blood pressure, reflex tachycardia, and a steal phenomenon in certain vascular beds. There have been multiple reports in the medical literature of serious adverse effects with sublingual nifedipine, including cerebral ischemia/infarction, myocardial infarction, complete heart block, and death. As a result of this, the FDA reviewed all data regarding the safety and efficacy of sublingual nifedipine for hypertensive emergencies in 1995, and concluded that the practice should be abandoned because it was neither safe nor efficacious.[8][9] An exception to the avoidance of this practice is in the use of nifedipine in the treatment of hypertension associated with autonomic dysreflexia in spinal cord injury.[10]

Early labor

Nifedipine has been used frequently as a tocolytic (agent that delays premature labor). A Cochrane review has concluded that it is comparable with magnesium sulfate and beta-agonists (such as ritodrine) with fewer side-effects.[11] Its role vis à vis atosiban is not established.

Other

Raynaud's phenomenon is often treated with nifedipine. A 2005 meta-analysis showed modest benefits (33% decrease in attack severity, 2.8-5 reduction in absolute number of attacks per week); it does conclude that most included studies used low doses of nifedipine.[12]

Topical nifedipine has been shown to be as effective as topical nitrates for anal fissures.[13]

Nifedipine is also used in high-altitude medicine to treat high altitude pulmonary edema.[14]

Other uses include painful spasms of the esophagus such as from cancer or tetanus. It is also used for the small subset of people with pulmonary hypertension.

Side effects

Nifedipine rapidly lowers 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). A more novel release system is GITS (Gastro-Intestinal Therapeutic System), which - according to Bayer - provides 24-hour continuous release through an osmotic push system. Recent trials with GITS include INSIGHT (for blood pressure)[15] and ACTION (for angina).[16]

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 they raise blood nifedipine levels. There are several possible mechanisms, including the lowering of CYP3A4 activity.[17]

Overdose

A number of persons have developed toxicity due to acute overdosage with nifedipine, either accidentally or intentionally, and via either oral or parenteral administration. The adverse effects include lethargy, bradycardia, marked hypotension and loss of consciousness. The drug may be quantitated in blood or plasma to confirm a diagnosis of poisoning in hospitalized patients or to assist in a medicolegal death investigation. Analytical methods usually involve gas or liquid chromatography and specimen concentrations are usually in the 100-1000 μg/L range.[18][19]

History

Nifedipine (initially BAY a1040) was developed by the German pharmaceutical company Bayer, with most initial studies being performed in the early 1970s.[20]

The use of nifedipine and related calcium channel antagonists was much reduced in response to 1995 trials that mortality was increased in patients with coronary artery disease who took nifedipine.[21] This study was a meta-analysis, and demonstrated harm mainly in short-acting forms of nifedipine (that could cause large fluctations in blood pressure) and at high doses of 80 mg a day and more.[22]

See also

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Lua error in package.lua at line 80: module 'strict' not found.
  2. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  3. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  4. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  5. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  6. ↑ Hypertension: management of hypertension in adults in primary care. Clinical guideline CG34. National Institute for Health and Clinical Excellence (NICE), June 2006. Fulltext index. ISBN 1-86016-285-1.
  7. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  8. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  9. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  10. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  11. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  12. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  13. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  14. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  15. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  16. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  17. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  18. ↑ Nifediac package insert, TEVA Pharmaceuticals, Sellersville, Pennsylvania, August, 2009.
  19. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  20. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  21. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  22. ↑ Lua error in package.lua at line 80: module 'strict' not found.

External links

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