WHO warns patients not to stop medicines newly classified as carcinogenic without doctor’s advice

The International Agency for Research on Cancer (IARC), the World Health Organization’s cancer research agency, has classified the medicines hydrochlorothiazide, voriconazole, and tacrolimus as Group 1 carcinogens (carcinogenic to humans). The medicines are used to treat high blood pressure, serious fungal infections, and to prevent organ rejection after transplantation, respectively.

However, the IARC has advised patients not to stop taking these medicines unless their doctors advise them to do so, as they are used to treat serious medical conditions and their benefits may outweigh the cancer risks in many patients.

According to the IARC, hydrochlorothiazide has been associated with an increased risk of squamous cell carcinoma of the skin and cancer of the lip. Long-term use may increase the skin’s sensitivity to ultraviolet (UV) radiation, which can contribute to DNA damage.

Voriconazole has been linked to an increased risk of squamous cell carcinoma of the skin, particularly in some patients receiving long-term treatment. Tacrolimus has been associated with a higher risk of non-Hodgkin lymphoma, as it suppresses the immune system and may reduce the body’s ability to detect and eliminate abnormal cells.

Patients taking hydrochlorothiazide or voriconazole are advised to protect themselves from excessive sun exposure by using sunscreen, wearing protective clothing, and limiting exposure to ultraviolet rays.

At the same time, experts have stressed that patients should not stop taking these medications on their own, as doing so could lead to serious health complications. Any decision to continue, change, or discontinue treatment should be made in consultation with a doctor.