Over-the-counter antihistamines linked to impaired fertility in men
Over-the-counter allergy drugs could have negative long-term side effects for male fertility, a review, published in the journal Reproduction, suggests.
Researchers highlight that patients should be cautioned against antihistamine overuse, and stress the need to further evaluate these negative effects in bigger clinical studies.
Symptoms of common mild allergies, such as hay fever, are mediated by histamine, a molecule produced by the body in response to certain conditions where the immune system detects a potential threat. Antihistamines are the most common treatment used to alleviate or prevent these symptoms, including a runny or blocked nose, wheezing, sneezing or skin rashes.
Allergies in the industrialised world are on the rise. Although the reasons for this are unclear, this phenomenon is leading to an increased use of allergy drugs like anti-histamines, both over-the-counter and prescribed. However, previous research shows that histamines are also involved in other bodily processes unrelated to allergic reactions, including sleep-wake regulation, sexual behaviour, and fertility. This suggests that blocking histamine activity to treat allergy symptoms may lead to undesirable side effects.
In this review, researchers at the Instituto de Biologia y Medicina Experimental (YBIME-CONICET), Argentina, looked at a mix of small and large scale animal research studies, conducted in the topic of histamines and fertility, conducted over the last 40 years. A number of studies reported adverse effects of anti-histamine on normal testicular function. The review concludes that anti-histamines are likely to affect the production of male sexual hormones in the testicles, which can lead to altered morphology and decreased motility of sperm, as well as a lower sperm count.
“More large-scale trials are needed to evaluate the possible negative effects of antihistamine on reproductive and sexual health. This can then lead to developing novel treatments to relieve allergy symptoms without compromising fertility”, Dr Carolina Mondillo, one of the authors involved in the study, said.
Although the research reviewed was mostly conducted in animals, and human studies are still limited, there is evidence that histamine plays a role in the male reproductive system. Dr Mondillo adds: “The data compiled in this review indicates the crucial involvement of histamine in orchestrating testicular functions, but even so there is still much to learn about the implicated mechanisms”.
In future work, the research group is planning on evaluating the role of histamines in the biology of testicular cell tumours.
The review “Potential deleterious effects of anti-histamines on male reproductive function” was published in Reproduction on 9 March 2018.
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