Men's Health: Understanding the Dual Effects of Medication on Sexual Function

Various diseases affect sexual function to varying degrees, especially during drug treatment. Depending on individual constitution, duration of medication, and dosage, sexual function can be directly impacted.

The effects of medication on sexual function can be divided into two aspects: one is decreased sexual function (decreased libido); the other is increased sexual function (hypersexuality). Currently, most clinically common drugs related to sexual function primarily suppress sexual function. This is especially true for patients requiring long-term medication for certain chronic diseases, often leading to decreased sexual function, adding new anxieties to the already suffering condition. For example, hydrochlorothiazide and beta-blockers (such as propranolol) are commonly used to treat early-stage hypertension in patients with hypertension. These drugs have the side effect of suppressing sexual function and reducing libido. The exact mechanism is unclear, but it may be due to the effect of these drugs raising blood sugar. In other cases, it may be related to hypokalemia.

Early-stage mild hypertension patients are mostly middle-aged, and the decline in sexual function is already a trend in middle-aged individuals; the impact of medication on sexual function is even more pronounced in these cases. The intermediate-acting antihypertensive drug hydralazine generally does not cause changes in sexual function. However, when the daily dose exceeds 200mg, approximately 5%–10% of men experience decreased libido, sometimes accompanied by impotence. Another antihypertensive drug, clonidine, can cause impotence or decreased libido in 10%–20% of patients.

Cimetidine is currently used to treat peptic ulcers, especially duodenal ulcers. Long-term use or high doses can lead to impotence and reduced fertility. Because this drug has anti-androgenic effects, it can reduce sperm count by 40%, so the dosage should be low and the duration of use should not be too long. Ranitidine is currently a relatively effective drug for treating peptic ulcers, with minimal impact on sexual function, but it is expensive; those who can afford it may consider using it.

The human cerebral cortex contains a sexual center, and the male lumbosacral spinal cord also contains erection and ejaculation centers. When these central nervous systems are excited, the corpora cavernosa of the penis become engorged with blood and erect. If the sexual central nervous system is inhibited, it will affect the engorgement and erection of the corpora cavernosa. Many clinically used drugs have an inhibitory effect on the sexual central nervous system, such as tranquilizers like diazepam, sildenafil, and chlorpromazine; sedatives like chlorpromazine, phenobarbital, and sepsis; and antihistamines like chlorpheniramine and diphenhydramine. Long-term and high-dose use can all cause impotence. Sedatives and hypnotics can reduce libido; therefore, it is best for insomniacs to use sleeping pills sparingly. Normal sexual activity is beneficial to sleep because the process of sexual activity brings both the body and mind to a high state of excitement and stimulation. After orgasm, excitement transitions to inhibition, and sleep quickly follows. Therefore, for people who frequently suffer from insomnia, appropriate sexual activity can not only provide restful sleep but may even help them break free from dependence on sleeping pills.

During puberty, the reproductive organs of males gradually mature under the influence of androgens. While androgens do not directly stimulate the sexual center, they can increase sexual arousal. Taking cardiac glycosides such as digitalis and digoxin can lower blood androgen (testosterone) levels, affecting male sexual arousal and potentially leading to erectile dysfunction. Long-term use of estrogen in men can also impair androgen function, causing decreased libido and erectile dysfunction.

Drugs that reduce vascular smooth muscle tension, such as propantheline bromide and atropine, can also cause erectile dysfunction with long-term use because they affect the blood flow to the corpora cavernosa for erection.

Currently, there are few drugs that can improve libido and sexual function; they are primarily sex hormones. For example, estrogen can restore libido and alleviate menopausal symptoms in postmenopausal women. Similarly, androgens can improve sexual function, increase libido, and even restore a youthful state in older men. However, sex hormones can cause numerous side effects. For example, women using high doses of androgens may experience hirsutism, acne, scrotal hypertrophy, and sodium retention, all of which are particularly bothersome. Therefore, the benefits and risks of using sex hormones after menopause remain a controversial issue.

Long-term use of cortisone at a daily dose of 20mg can significantly inhibit the hypothalamic-pituitary-adrenal axis. Increasing the dose further can produce more side effects, causing complications related to sexual function, including increased blood sugar, suppression of pituitary gonadotropin secretion, inhibition of spermatogenesis, and various effects on the ovaries. Long-term use of cortisone is mostly seen in patients with chronic diseases. Chronic diseases themselves can affect sexual function in both men and women, a factor that must be considered.

Another drug that can improve sexual function and increase libido is levodopa, used to treat Parkinson's disease. There are even reports that this drug can induce a state of intense sexual desire; however, it is not suitable for healthy individuals.

Some medications improve a patient's overall condition by treating the disease or symptoms, thereby indirectly improving sexual function. For example, patients with anxiety or depression often experience decreased libido and impotence. This is related to a lack of knowledge about sexual physiology or unsatisfactory sexual experiences. Administering antidepressants and anti-anxiety medications, such as diazepam and chlorpromazine, can improve the patient's anxiety and depression, leading to a more cheerful and optimistic mood, and thus, a natural recovery of sexual function. Therefore, these medications can be tried for some women experiencing frigidity due to stress and depression.