Tamsulosin Tamsulosin hydrochloride is used to treat benign prostatic hypertrophy (BPH) and urination problems. However, this medicine may reduce the volume of seminal fluid and/or cause anejaculation (inability to ejaculate). Testosterone Testosterone replacement therapy has a strong negative effect on seminal fluid production. One of the most likely side effects of testosterone treatment is a very low concentration of sperm or a complete absence of sperm in the semen. When testosterone is taken, the hormone signals that instruct the testicles to produce testosterone and semen are blocked. Natural testosterone production then stops, causing testosterone levels in the testicles to plummet, where active seminal fluid production cannot be maintained. In most men, this effect is reversible, although it may take six to 12 months or more for sperm production to return to normal. Ketoconazole Ketoconazole is used to treat fungal infections, this medicine is usually applied to the skin as a cream, ointment or powder. Its use on the skin is thought to have no effect on fertility. But when taken orally, in pill form, ketoconazole also harms testosterone production and reduces seminal fluid production. 5-alpha-reductase inhibitors These drugs are used to treat male pattern baldness and benign prostatic hyperplasia (BPH). However, it is also possible that their intake reduces the volume of seminal fluid, as well as the number and motility of sperm. Studies have shown that stopping these drugs may improve ejaculate volume and sperm count and quality. Up to 5% of men who take such drugs for one of two reasons (alopecia or an enlarged prostate) have a decrease in their sperm count. Also, these drugs can reduce libido (sexual desire). However, in most cases this effect is also reversible when the testosterone-5-alpha reductase inhibitor is stopped. Other drugs Some other prescription drugs can cause fertility problems in men, although most of them are reversible. These include: Anti-epileptic drugs such as carbamazepine, oxcarbazepine and valproate. Antiretroviral drugs, drugs used primarily to stop HIV from replicating; Certain antibiotics (used for bacterial infections); Blood pressure medications, such as nifedipine and spironolactone; Cimetidine, which can be used to treat acid reflux and ulcers; Colchicine, a medicine for gout; Sulfasalazine, used to treat ulcerative colitis or rheumatoid arthritis. References: 1. Cleveland Clinic. Can Drugs Lower Your Sperm Count? 2. Society for Endocrinology. Testosterone 3. National Center for Biotechnology Information (NCBI).Finasteride and male fertility