Pharmacology Methenamine salts are used as urinary antiseptics. The reason they lack systemic antibacterial action is that they are : A Not absorbed into systemic circulation after oral use B Rapidly metabolized by liver drug metabolizing enzymes C Converted to formaldehyde at low urinary pH D Substrates for active tubular secretion 💡 Explanation Methenamine salts are used as urinary antiseptics. The reason they lack systemic antibacterial action is that they are : ✓ Correct Answer: C. Converted to formaldehyde at low urinary pH