When prescribing antibiotic therapy for an acute illness in a patient with acne vulgaris, should the daily antibiotics used to treat the acne (i.e., minocycline, tetracycline) be withheld?—TERESA MORGAN, ARNP, Kevil, Ky.

At issue is whether the potential adverse effects are additive when systemic antibiotics used to treat acne vulgaris (typically erythromycin or a tetracycline derivative) are concurrently administered with antimicrobials used to treat an acute illness (which can vary depending on the organ system affected and the likely causative pathogen). The oral antibiotics used to treat acne are predominantly metabolized by the liver. Therefore, other antibiotics with hepatic excretion may potentially prolong the half-life of the acne medications or vice versa. A conservative approach to this situation is to withhold the daily oral antibiotic for acne while the patient is receiving systemic antibiotic therapy for the acute illness.—Philip R. Cohen, MD (85-3)