August 6th, 2012

Hydrochlorothiazide and Nifedipine Linked to Increased Risk for Lip Cancer

The antihypertensive drugs hydrochlorothiazide and nifedipine have been linked to a significantly increased risk for lip cancer in a new study published in the Archives of Internal Medicine. The link is plausible, write the authors, since the drugs are known to be photosensitizing.

Using a large cohort from the Kaiser Permanente system, researchers at Kaiser Permanente and Stanford identified 712 patients with lip cancer and 22,904 matched controls. Here are the odds ratios for people with at least a 5-year exposure to antihypertensive drugs compared with no use:

  • hydrochlorothiazide: 4.22 (2.82-6.31)
  • hydrochlorothiazide-triamterene: 2.82 (1.74-4.55)
  • lisinopril: 1.42 (0.95-2.13)
  • nifedipine: 2.50 (1.29-4.84)
  • atenolol: 1.93 (1.29-2.91)

The atenolol result was no longer significant when the use of other drugs was taken into account. The authors note that because lip cancer is “a relatively infrequent form of cancer, it is not surprising that associations with antihypertensive drugs have not been observed in large clinical trials.”

In their conclusion, the authors say physicians who prescribe “photosensitizing drugs should ascertain whether patients are at high risk of lip cancer because of their fair skin and long-term sun exposure and discuss lip protection with them. 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.”

In an accompanying editor’s note, Mitchell Katz wrote that “it is likely that patients receiving these agents are also at increased risk of basal cell and squamous cell cancers of the skin (these cancers are not tracked by the cancer registry used for this study). 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 for everyone, regardless of whether they are receiving a photosensitizing agent. When initiating use of photosensitizing agents for our patients, we need to remind them of these simple measures to avoid sun exposure.”

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