Heartburn Drug Prilosec Can Interfere with Plavix
The U.S. Food and Drug Administration (FDA) has new data showing that omeprazole, a medicine used to reduce stomach acid and treat frequent heartburn, can reduce the anti-blood clotting effect of clopidogrel, better known as Plavix.
Plavix is the world’s second most prescribed drug, with global sales of about $9 billion.
A key ingredient of omeprazole, the generic name for the proton pump inhibitor Prilosec and Prilosec OTC, blocks the conversion of clopidogel into its active form, reducing its ability to prevent blood clots by 45%. The reduction in effectiveness occurred whether the drugs were together or as much as 12 hours apart.
Since Plavix can cause stomach upset and increase the risk of stomach bleeding, a medication such as Prilosec is often used in combination to block the production of stomach acid.
The FDA has requested that the following information be included on the packaging label and emphasized for patients who are prescribed Plavix:
• Patients using clopidogrel should consult with their healthcare provider if they are currently taking or considering taking omeprazole, including Prilosec OTC.
• Both clopidogrel and omeprazole can provide significant benefits to patients, and patients should always consult with their healthcare professional before starting or stopping any medication.
• It is very important that patients talk with their healthcare professional about any over-the-counter (OTC) drugs they are taking before starting or while using clopidogrel
Plavix was also found last year to interact negatively with Nexium, another proton pump inhibitor, when Medco Health Solutions reported that taking the combination significantly increased patients chance of being hospitalized for heart attack, stroke, or chest pain.
Other drugs may also inhibit the same enzyme activity and have a similar effect, and should therefore be avoided as well when taking Plavix. These drugs include cimetidine (Tagamet), fluconazole (Diflucan), ketoconazole (Nizoral), voriconazole (VFEND), etravirine (Intelence), felbamate (Felbatol), fluoxetine (Prozac), fluvoxamine (Luvox), and ticlopidine (Ticlid).
Patients prescribed Plavix who need a medication to reduce stomach acid can use an antacid such as Maalox or Mylanta, or another acid reducer, such as Zantac (ranitidine), Pepcid (famotidine), or Axid (nizatidine). The FDA does not believe that these medicines will interfere with the anti-clotting activity.
The FDA says it is continuing to investigate other drug interactions with clopidogrel and plans to present on this issue at the next meeting of FDA's Drug Safety Oversight Board in November.