Small increased risk of certain types of skin cancer associated with the use of hydrochlorothiazide

There is a small increased risk of developing basal cell carcinoma and squamous cell carcinoma in long-term use of blood pressure medicine containing hydrochlorothiazide. This follows from a review of new studies and available data undertaken by the European Medicines Agency, EMA.

The European Medicines Agency, EMA, has reviewed new studies and available data reported to the European adverse reactions database (EudraVigilance), concluding that long-term use of hydrochlorothiazide may increase the risk of basal cell carcinoma and squamous cell carcinoma.

Hydrochlorothiazide may cause increased photosensitivity, which could be the possible cause of the increased risk of developing the two types of cancer.

There have been no observations of malignant melanoma.

Hydrochlorothiazide is a diuretic which is used in the treatment of hypertension. About 258,000 people in Denmark received treatment with the medicine in 2017.

Changes to the package leaflets

Following the decision made by the EMA, the increased risk will be written into all package leaflets (product information) of hydrochlorothiazide-containing medicines. The recommendations of the EMA will appear from the package leaflets, including

• That patients should check their skin regularly and consult a doctor if they discover any suspicious skin changes or lesions,
• That patients should limit exposure to sunlight and UV rays and use adequate protection during exposure to the sun,
• That it may be relevant for patients with a history of basal cell carcinoma and squamous cell carcinoma to consider switching to a different type of medicine.

Here you can see a list of all medicines containing hydrochlorothiazide (in Danish only).

Please see the EMA's recommendations here (page 7).

Here you can read the Danish Health Authority's assessment of the EMA announcement and how it affects the Danish treatment guides and what patients should do (in Danish only).

DHPCs in Danish have been sent out to doctors and other healthcare professionals with information about the EMA review of hydrochlorothiazide and the background leading to the changes to the package leaflets: Hydrochlorothiazide – Risk of non-melanoma skin cancer (basal cell carcinoma and squamous cell carcinoma) – in Danish only.