Pay more than lip service to sun-screen advice for antihypertensive users

By Caroline Price, Senior MedWire Reporter

Users of common antihypertensive drugs, such as hydrochlorothiazide and nifedipine, may be at increased risk for developing lip cancer.

A study revealed that among White individuals, long-term use of such photosensitizing antihypertensives raised the risk for lip cancer as much as a fourfold.

Authors Gary Friedman (Stanford University, California, USA) and colleagues say that, while lip cancer is rare and the increased risk may be outweighed by the benefits of antihypertensive medication, physicians prescribing photosensitizing drugs should recommend lip protection to patients with fair skin or long-term sun exposure.

"Although not confirmed by clinical trials, likely preventive measures are simple: a hat with a sufficiently wide brim to shade the lips and lip sunscreens," they write in the Archives of Internal Medicine.

The researchers analyzed antihypertensive prescriptions dispensed to 712 non-Hispanic White patients who developed lip cancer between 1994 and 2008, and 22,904 matched control individuals.

Receipt of three or more prescriptions of hydrochlorothiazide/triamterene, lisinopril, or nifedipine was 1.4-2.3 times more likely among cases than controls, after adjusting for cigarette smoking. No association was found for the non-photosensitizing drug atenolol.

The likelihood of lip cancer seemed to increase with longer duration of hydrochlorothiazide, hydrochlorothiazide/triamterene, or nifedipine use, irrespective of whether any of the other drugs were also used. For example, for hydrochlorothiazide, a 1-5-year supply was associated with a 2.0-fold higher chance of lip cancer, while a 5-year or longer supply conferred a 4.2-fold greater likelihood for the disease, relative to no use.

The association with lip cancer was no longer significant for the photosensitizer lisinopril after other drug use was excluded.

In an accompanying Editor's Note, Mitchell Katz comments: "Hypertensive medications are commonly prescribed, yet physicians and patients may be unaware that many of these agents are photosensitizing."

Katz adds that although the study focused on lip cancer, "it is likely that patients receiving these agents are at increased risk of basal cell and squamous cell cancers of the skin." These cancers, he points out, are not tracked by the registry used by Friedman et al.

"The findings are important because simple interventions, such as lip protector, sunscreen, large-brim hats, rash guard swim shirts, and avoiding times of the day when the sun is most intense, are likely to decrease the harmful effects of the sun," Katz writes.

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