Azathioprine is an active ingredient belonging to the class of antimetabolites that has been used for decades in the treatment of numerous autoimmune diseases and transplantation settings. First synthesized in 1957, it is included in the World Health Organization’s list of essential medicines. This article explores the drug’s mechanism of action and addresses common concerns about potential side effects and contraindications.
What is Azathioprine, and what is it used for?
Azathioprine is used to suppress the immune response in conditions where the immune system mistakenly attacks healthy tissues in the body, and is also used to prevent rejection of transplanted organs. In addition to its most common use, the drug is widely used in the treatment of chronic conditions such as:
- Rheumatoid arthritis
- Systemic lupus erythematosus (SLE)
- Inflammatory bowel disease, such as Crohn’s disease and ulcerative colitis
- Granulomatosis with polyangiitis (GPA)
Its use is generally long-term, often in combination with corticosteroids or other immunosuppressants, to keep the disease under control and reduce the frequency of flare-ups.
How does Azathioprine work?
Azathioprine’s mechanism of action is based on the selective suppression of the proliferation of immune cells, particularly T and B lymphocytes, which are involved in the autoimmune response. Once taken, the molecule is converted in the liver to 6-mercaptopurine, which interferes with the synthesis of DNA and RNA, thereby inhibiting cell division.
This process helps reduce inflammation and limit the immune system’s aggression toward body tissues, improving symptoms and slowing disease progression.
Myths to clarify: hair, weight loss, sun, and pregnancy
Azathioprine is classified by the International Agency for Research on Cancer (IARC) as a Group 1 human carcinogen. For this reason, its administration must be carefully supervised by a specialist, and appropriate precautions must be taken. Below, we address the most common concerns related to its use.
Does Azathioprine cause weight gain?
Azathioprine has no direct action on appetite or metabolism. Any weight changes are most often related to the underlying disease, concomitant use of corticosteroids, or lifestyle changes. However, treatment of some diseases with Azathioprine may indirectly contribute to stabilization and/or weight gain as a result of overall improvement in the patient’s health.
Does it cause hair loss?
Hair loss is a rare but possible side effect related to the immunosuppressive nature of the drug. It can occur in predisposed individuals. However, it is essential to distinguish whether the thinning is caused by the therapy or by the autoimmune disease itself, which often involves the skin and adnexa.
Should one avoid sun exposure?
Excessive UV exposure can increase the risk of skin reactions, skin lesions, and, in the long term, the development of skin cancers. Taking immunosuppressants such as Azathioprine may exacerbate this vulnerability. It is therefore advisable to use high sun protection and reduce direct sun exposure, especially in the summer months.
Can it be used during pregnancy?
Azathioprine is not considered teratogenic in humans and, in many cases, can be used in pregnancy under strict medical supervision. Recent studies have suggested a possible association with adverse events such as intrauterine growth retardation and neonatal immunosuppression. Still, it is unclear whether these are caused directly by the drug or by the underlying pathology. For this reason, intake during pregnancy should be evaluated on a case-by-case basis in consultation with the medical specialist.
Flarer and the distribution of Azathioprine
At Flarer, we are committed to supplying high-quality active ingredients, such as Azathioprine, intended for the production of immunosuppressive therapies crucial for treating complex diseases. Thanks to our consolidated experience and a network of certified partners, we offer pharmaceutical companies a complete service, from selection to distribution, guaranteeing reliability, safety, and traceability.
For more information about our solutions or to schedule a personalized consultation, please don’t hesitate to contact our consultants.