To the Editor.—
The authors of the article, "Lipoid Pneumonia Caused By Methenamine Mandelate Suspension" (225:1524, 1973), concluded that "Simply, methenamine tablets can be crushed and given with food to problem patients."Methenamine mandelate (Mandelamine) is available as an entericcoated tablet (0.25, 0.5, 1.0 gm). The antibacterial effect of methenamine is dependent on the release of formaldehyde from the drug in acid media.Since 10% to 30% of the drug is prematurely converted to formaldehyde by acidic stomach contents,1 an enteric coating is applied to the oral tablets.Although published studies using methenamine or its salts do not appear to support or disprove the rationale for enteric coating of methenamine,2 reservations should be made before crushing any entericcoated drug product.
Jansen JR. Crushed Enteric-Coated Methenamine Tablets. JAMA. 1973;226(11):1361. doi:10.1001/jama.1973.03230110049026