Different calcium channels are present in vascular tissue and cardiac tissue; an in vitro study on human vascular and cardiac tissues comparing how selective various calcium channel blockers are for vascular compared to cardiac tissue found the following vascular/cardiac tissue ratios: mibefradil 41, felodipine 12; nifedipine 7, amlodipine 5, and verapamil 0.2.:172
Felodipine is a member of the 1,4-dihydropyridine class of calcium channel blockers.:20–21 It is a racemic mixture, and is insoluble in water but is soluble in dichloromethane and ethanol.:25
The Swedish company Hässle, a division of Astra AB, discovered felodipine; it filed a patent application in 1979 claiming felodipine as an antihypertensive drug. Astra partnered this drug and others with Merck & Co. in the US under a 1982 agreement between the companies. The drug was approved by the FDA in 1991 after a three and a half year review; the drug entered a very crowded market the included the other calcium channel blockers nifedipine, verapamil, nicardipine, and isradipine. The FDA gave the drug a 1C rating, meaning that it found little difference between felodipine and the drugs already approved for the same use.
In 1994 Astra AB and Merck changed their partnership to a joint venture called Astra Merck, and in 1998 Astra (by that time, AstraZeneca) bought out Merck's rights in the joint venture.
The first generics became available in Sweden in 2003 and in the US in 2004.:155
In April 2016, AstraZeneca announced that they were selling the right to market felodipine in China to China Medical System Holdings for $310 million; AZ would continue to manufacture the drug.
^ abcJoshi GS, Burnett JC, Abraham DJ (2003). "Cardiac Drugs: Antianginal, Vasodilators, Antiarrhythmic". In Abraham DJ (ed.). Burger's medicinal chemistry and drug discovery. Volume 3: Cardiovascular Agents and Endocrines (6th ed.). Hoboken, N.J.: Wiley. ISBN9780471270904.
^Astrazeneca AB v. Mutual Pharmaceutical Co. (United States Court of Appeals for the Federal Circuit 2004). Text
^US patent 4,264,611, Berntsson, Peder; Carlsson, Stig & Gaarder, Jan et al., "2,6-Dimethyl-4-2,3-Disubstituted Phenyl-1,4-Dihydro-Pyridine-3,5 Dicarboxylic Acid-3,5-Asymmetric Diesters having Hypotensive Properties, as well as Method for Treating Hypertensive Conditions and Pharmaceutical Preparations Containing Same", issued 28 April 1981, assigned to Aktiebolaget Hassle
^George J (28 July 1997). "Secret of Astra Merck". Philadelphia Business Journal. Philadelphia. Retrieved 7 November 2016.