Laropiprant (INN) was a drug used in combination with nicotinic acid to reduce blood cholesterol (LDL and VLDL) that is no longer sold, due to increases in side-effects with no cardiovascular benefit. Laropiprant itself has no cholesterol lowering effect, but it reduces facial flushes induced by nicotinic acid.
Merck & Co. planned to market this combination under the trade names Cordaptive in the US and Tredaptive in Europe. Both brands contained 1000 mg of nicotinic acid (niacin) and 20 mg of laropiprant in each tablet.[2]
Mechanism of action
Nicotinic acid in cholesterol lowering doses (500–2000 mg per day) causes facial flushes by stimulating biosynthesis of prostaglandin D2 (PGD2), especially in the skin. PGD2dilates the blood vessels via activation of the prostaglandin D2 receptor subtype DP1, increasing blood flow and thus leading to flushes.[2][3] Laropiprant acts as a selective DP1receptor antagonist to inhibit the vasodilation of prostaglandin D2-induced activation of DP1.[2]
Taking 325 mg of aspirin 20–30 minutes prior to taking nicotinic acid has also been proven to prevent flushing in 90% of patients, presumably by suppressing prostaglandin synthesis,[4] but this medication also increases the risk of gastrointestinal bleeding,[5] though the increased risk is less than 1 percent.[6]
History
In the mid-2000s, in a trial with 1613 patients, 10.2% patients stopped taking the medication in the combination drug group versus 22.2% under nicotinic acid monotherapy.[7]
On January 11, 2013, Merck & Co Inc. announced they were withdrawing the drug worldwide as a result of European regulators recommendations.[10]
The Heart Protection Study 2-Treatment of HDL to Reduce the Incidence of Vascular Events (HPS2-THRIVE) involved more than 25,000 adults. The treatment group received 2 g of extended-release nicotinic acid and 40 mg of laropiprant daily. Study results, reported in July 2014, showed that the combination of nicotinic acid and laropiprant did not have any beneficial effects when compared with a placebo treatment and had an increase in adverse effects.[11]
^Sørensen HT, Mellemkjaer L, Blot WJ, Nielsen GL, Steffensen FH, McLaughlin JK, Olsen JH (September 2000). "Risk of upper gastrointestinal bleeding associated with use of low-dose aspirin". The American Journal of Gastroenterology. 95 (9): 2218–2224. doi:10.1111/j.1572-0241.2000.02248.x. PMID11007221. S2CID33742424.
^Lai E, De Lepeleire I, Crumley TM, Liu F, Wenning LA, Michiels N, et al. (June 2007). "Suppression of niacin-induced vasodilation with an antagonist to prostaglandin D2 receptor subtype 1". Clinical Pharmacology and Therapeutics. 81 (6): 849–857. doi:10.1038/sj.clpt.6100180. PMID17392721. S2CID2126240.