Felodipine
Encyclopedia
Felodipine is a calcium channel blocker
(calcium antagonist), a drug used to control hypertension
(high blood pressure). It is marketed under the brand name Plendil by AstraZeneca
and Renedil by Sanofi-Aventis
. The formulation patent for the substance expired in 2007.
AstraZeneca dropped Plendil from its support and AZ&Me free Rx access program in October 2008.
can cause toxic effects. Oral administration of felodipine is first metabolized in the gastrointestinal tract and liver by the enzyme CYP3A4
. Grapefruit juice contains bergamottin
which is found to have an inhibiting effect over this enzyme and as a result the bioavailability
of the drug increases, raising the risk for abnormal side effects.
use cautiously with pregnancy, impaired hepatic function.
Calcium channel blocker
A calcium channel blocker is a chemical that disrupts the movement of calcium through calcium channels.CCB drugs devised to target neurons are used as antiepileptics. However, the most widespread clinical usage of calcium channel blockers is to decrease blood pressure in patients with...
(calcium antagonist), a drug used to control hypertension
Hypertension
Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
(high blood pressure). It is marketed under the brand name Plendil by AstraZeneca
AstraZeneca
AstraZeneca plc is a global pharmaceutical and biologics company headquartered in London, United Kingdom. It is the world's seventh-largest pharmaceutical company measured by revenues and has operations in over 100 countries...
and Renedil by Sanofi-Aventis
Sanofi-Aventis
Sanofi S.A. is a multinational pharmaceutical company headquartered in Paris, France, the world's fourth-largest by prescription sales. Sanofi engages in the research and development, manufacturing and marketing of pharmaceutical products for sale principally in the prescription market, but the...
. The formulation patent for the substance expired in 2007.
AstraZeneca dropped Plendil from its support and AZ&Me free Rx access program in October 2008.
Interactions
Studies dating back to 1989 have suggested that felodipine in combination with grapefruit juiceGrapefruit juice
Grapefruit juice is the fruit juice from grapefruits. It is rich in Vitamin C and ranges from sweet-tart to very sour. It is considered by some cultures to be a mystical tonic which promotes health and vigor. Certain civilizations have had holy men who live on Grapefruit juice alone...
can cause toxic effects. Oral administration of felodipine is first metabolized in the gastrointestinal tract and liver by the enzyme CYP3A4
CYP3A4
Cytochrome P450 3A4 , a member of the cytochrome P450 mixed-function oxidase system, is one of the most important enzymes involved in the metabolism of xenobiotics in the body. CYP3A4 is involved in the oxidation of the largest range of substrates of all the CYPs. As a result, CYP3A4 is present in...
. Grapefruit juice contains bergamottin
Bergamottin
Bergamottin is a natural furanocoumarin found principally in grapefruit juice. It is also found in the oil of bergamot, from which it was first isolated and from which its name is derived. To a lesser extent, bergamottin is also present in the essential oils of other citrus fruits...
which is found to have an inhibiting effect over this enzyme and as a result the bioavailability
Bioavailability
In pharmacology, bioavailability is a subcategory of absorption and is used to describe the fraction of an administered dose of unchanged drug that reaches the systemic circulation, one of the principal pharmacokinetic properties of drugs. By definition, when a medication is administered...
of the drug increases, raising the risk for abnormal side effects.
Contraindications and cautions
contraindicated with allergy to felodipine or other calcium channel blockers, sick sinus syndrome, heart block(second and third degree, lactation.use cautiously with pregnancy, impaired hepatic function.