Secondly, side effects that involve sexual issues are frequently not reported to doctors because of embarrassment. So, the actual rate of sexual dysfunction caused by medicines might be higher than reported. The mechanism of sexual function is not fully understood. However, in general, the neurotransmitter dopamine increases sexual function, whereas the neurotransmitter serotonin inhibits sexual function. The hormone testosterone is important, as are the blood vessels involved in producing an erection.
Sex drive is influenced by reproductive hormones, particularly testosterone.
Testosterone is required for sexual arousal and medicines that reduce testosterone levels are likely to reduce sex drive. Libido is also affected by your general emotional and physical health. Therefore, medicines that affect any of these aspects, even indirectly by causing drowsiness, lethargy, weight gain or confusion, have the potential to reduce your sex drive. This occurs after stimulation of alpha receptors in the prostate gland and seminal vesicles. Medicines that block alpha receptors can therefore prevent or delay ejaculation.