If you are currently being treated with any of the following medications, you should not use cayenne preparations without first talking to your healthcare provider.

ACE-Inhibitors
Using capsaicin cream on the skin may increase the risk of cough associated with angiotensin-converting enzyme (ACE) inhibitors, medications used to regulate blood pressure including captopril, enalapril, and lisinopril. If individuals using capsaicin cream while on these medications develop a cough, use of the cream should be discontinued.

Aspirin
One study found that capsaicin (when taken together with aspirin) reduced irritation and damage to the stomach normally associated with this medication.

Blood-thinning medications and herbs
In theory, capsaicin may increase the risk of bleeding associated with certain blood-thinning medications (such as warfarin and low molecular weight heparin) and herbs (such as ginkgo and garlic). However, this theory has not been tested. Until more information is available, extreme care should be taken if considering use of capsaicin when on a blood thinning medication, in a class known as anticoagulants, or blood thinning herb.

Theophylline
Regular use of cayenne may increase the absorption of theophylline, a medication used to treat asthma, thereby increasing the risk of toxicity associated with this medication.