Some commonly used antihypertensive drugs — hydrochlorothiazide and nifedipine — might increase the risk for lip cancer, according to a case-control study in the Archives of Internal Medicine.

Using a California-based cancer registry, researchers matched some 700 non-Hispanic white adults diagnosed with lip cancer to some 23,000 controls free of lip cancer. Patients who filled three or more prescriptions for hydrochlorothiazide, hydrochlorothiazide-triamterene, and nifedipine — all photosensitizing agents — had roughly double the risk for lip cancer relative to those with no prescriptions filled. Risks increased with duration of use. Atenolol, which is non-photosensitizing, was not associated with increased risk.

The authors write that photosensitizing drugs may absorb energy from sunlight, which leads to the release of electrons. This then produces free radicals that can cause inflammation.

An Archives‘ editor writes: “When initiating use of photosensitizing agents for our patients, we need to remind them of … simple measures to avoid sun exposure.”

Source: Archives of Internal Medicine