Microx (Pennwalt), a new low-dosage formulation of the thiazide-type diuretic metolazone (Zaroxolyn; Diulo), was recently marketed in the USA. The manufacturer claims that the low dose of controls hypertension with less potassium loss, making it safer than other diuretics and as effective as combination drugs, such as Dyazide, that include both a thiazide and a potassium-sparing diuretic. Medical Letter consultants generally do not recommend Dyazide or other fixed-dose combinations for treatment of hypertension.

Recent advertisements for indapamide (Lozol - Rorer), an oral antihypertensive/diuretic (Medical Letter, 26:17, 1984), claim that the drug, unlike thiazide diuretics, does not significantly increase serum cholesterol and has a minimal impact on potassium. Indapamide has no thiazide ring but, like chlorthalidone (Hygroton; and others) and hydrochlorothiazide (HydroDiuril; and others), it does have a sulfamoyl benzamide moiety, which is probably responsible for its natriuretic and diuretic effects. Unlike the thiazides, it also has a methylindoline moiety, which apparently decreases...

As the weather becomes warmer, physicians may see more photosensitivity reactions due to systemic or topical drugs, perfumes, cosmetics or sunscreens. Even brief exposure to sunlight in warm or cold weather can cause intense cutaneous reactions in patients with drug-induced photosensitivity, and some patients may continue to be sensitive to sunlight long after stopping use of the offending agent.

A reader has questioned why the label for the COX-2 selective NSAID celecoxib (Celebrex, and generics), which contains a sulfonamide moiety, states that it is contraindicated for use in patients with an allergy to sulfonamides, while the labels of some other sulfonamide drugs recommend either caution or no precautions at all. The concept of cross-reactivity among sulfonamide drugs, particularly between antibacterial and nonantibacterial sulfonamides, has been controversial for many years.

American College of Cardiology/American Heart Association (ACC/AHA) guidelines for treatment of hypertension were last published in 2018. Treatment of hypertensive urgencies and emergencies is not discussed here.