Subsalicylates

Subsalicylates are salts or esters derived from salicylic acid in which the carboxyl group is bound to a metal cation or another moiety. Common examples include sodium subsalicylate and bismuth subsalicylate. In medicinal contexts, subsalicylates are recognized for delivering the salicylate component, sometimes with additional properties from the accompanying metal.

In pharmaceutical use, the best-known subsalicylate is bismuth subsalicylate, the active ingredient in products such as Pepto-Bismol, which is used to treat upset stomach, indigestion, and diarrhea. Sodium subsalicylate has historically served as an analgesic and anti-inflammatory agent. The salicylate portion contributes analgesic and anti-inflammatory effects, while the accompanying metal or moiety can impart additional actions, such as the protective and antimicrobial properties seen with bismuth.

Mechanistically, salicylates inhibit cyclooxygenase enzymes, reducing the synthesis of prostaglandins involved in pain and inflammation. In bismuth subsalicylate, the bismuth component can form a protective layer on the gastric mucosa and may exhibit antimicrobial activity, contributing to therapeutic effects in gastrointestinal upset.

Safety and regulation considerations include the potential for salicylate toxicity at high doses and indications of risk for Reye’s syndrome in children and adolescents with viral illnesses. Bismuth subsalicylate can cause harmless darkening of stools and tongue. Subsalicylates may interact with other NSAIDs, anticoagulants, and certain chronic medications, so use should follow medical guidance.