What drug can cause a harmless black discoloration of the tongue?

Bismuth subsalicylate is known to cause a harmless black discoloration of the tongue, a phenomenon that can occur when this medication is taken. This darkening is due to a reaction between the bismuth component of the drug and sulfur compounds in the saliva, leading to the formation of bismuth sulfide, which is black.

This effect is generally temporary and usually resolves after discontinuation of the medication. It is important for patients to be aware of this potential side effect to avoid unnecessary concern when they notice the discoloration. The phenomenon is benign and does not indicate any serious underlying issue.

In contrast, amoxicillin is an antibiotic that does not cause tongue discoloration, nor does omeprazole, which is used to reduce stomach acid. Lubiprostone, a medication used for chronic constipation, is also not associated with causing tongue discoloration. Understanding the specific side effects associated with each medication helps in better patient education and management.