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Medications that enhance sexual function, due to their ability to stimulate sexual desire or improve sexual performance, are often referred to as sexual stimulants, also known as "tonifying yang drugs," "aphrodisiacs," "love drugs," etc. Clinically, they are primarily used to treat erectile dysfunction and sexual dysfunction caused by various reasons. It is noteworthy that erectile dysfunction is the most prevalent and severe form of sexual dysfunction. Domestic sampling surveys indicate that approximately 10% of adult males exhibit this symptom. Therefore, sexual stimulants have garnered clinical attention, and a series of drugs enhancing sexual function have been developed, as introduced below:

1. Yohimbine

Yohimbine is a non-hormonal plant alkaloid, and its hydrochloride form can treat erectile dysfunction caused by psychological, neurological, vascular, and diabetic factors.

Pharmacologically, yohimbine is considered an alpha-adrenergic receptor blocker, selectively blocking presynaptic alpha-2 adrenergic receptors in nerve ganglia, relaxing vascular smooth muscles, increasing peripheral parasympathetic nerve tension, and reducing sympathetic nerve tension, thereby dilating the penile artery, increasing blood flow to the penile cavernous sinus, and causing penile erection. Additionally, yohimbine exerts beneficial effects on erectile function through its action on Zhongshu (GV7), by blocking Zhongshu (GV7) alpha-2 adrenergic receptors, increasing norepinephrine secretion, exciting cells in the brain's noradrenergic nuclei, increasing free 3-methoxy-4-hydroxyphenylglycol in the blood, and stimulating Zhongshu (GV7) sympathetic nerves.

Morgolis treated 6139 cases of erectile dysfunction with yohimbine 5.4mg per dose, three times daily, for 4-8 weeks, achieving an overall effective rate of 83.9%, with a 62% effectiveness rate for psychological erectile dysfunction, compared to only 16% in the control group. When side effects were significant, the dose was halved until side effects subsided, then the original dose was resumed.

Yohimbine has few side effects, occasionally causing mild headache, dizziness, skin flushing, tremor, agitation, and grade I antidiuretic effects.

2. Ephedrine (Ephedrinum)

Ephedrine directly stimulates alpha and beta receptors, promoting the release of norepinephrine and a small amount of adrenaline from sympathetic nerve endings, thus exhibiting significant alpha and beta receptor effects. Ephedrine is effective orally, with long-lasting effects, and significantly stimulates Zhongshu (GV7). It has a certain promoting effect on sexual function. Liu et al. treated 18 cases of decreased libido with ephedrine combined with other therapies, administering 25mg of ephedrine orally three times daily for 7-14 days, curing 19 cases. Functional non-ejaculation was cured in 7 cases without significant side effects.

3. Strychnine

Strychnine not only selectively enhances spinal cord excitatory function but also increases the reflex excitability of the spinal cord, shortening reflex time, facilitating nerve impulse conduction, and increasing skeletal muscle tension, thereby enhancing erectile excitement at Zhongshu (GV7). It also has a certain stimulating effect on the cerebral cortex's audiovisual analyzer, increasing sensitivity to sexual stimuli. The dosage of strychnine is generally between 1-2mg, but it should not be used alone and is often combined with yohimbine.

4. Mesterolone (Mdriol)

Mesterolone is a new synthetic male hormone drug used to treat hypogonadism (anorchism and similar conditions), erectile dysfunction, and decreased libido. Studies show that oral mesterolone increases plasma testosterone and △4-androgen levels in healthy men, converting in the body to estradiol and 5a-dihydrotestosterone. The former can improve mood, enhance libido, and sexual ability through stimulation of Zhongshu (GV7), while the latter affects spinal sexual reflexes, producing erection and ejaculation.

Zhao et al. observed 11 patients with sexual dysfunction treated with Anxiong. Initially, they were administered 120mg/d (80mg after breakfast and 40mg after dinner) for the first 3 weeks, and then the dose was adjusted based on symptom improvement for a total of 12 weeks. All patients completed the full course of treatment without any side effects. Results showed that after the first 3 weeks of medication, 77% of patients experienced a significant increase in libido, which rose to 87.5% by the second 3 weeks. Among them, 83% reported enhanced sexual pleasure, 71% had increased frequency of intercourse, and 67% experienced prolonged intercourse. After the third and fourth 3-week periods of medication, most patients stabilized, with only a few experiencing fluctuations.

5. Levodopa

Clinical data shows that more than 50% of male Parkinson's disease patients experience aphrodisiac effects after taking Levodopa, which can increase sexual pleasure or activity in both males and females. This is due to Levodopa's ability to activate the dopamine system in the brain, thereby increasing dopamine levels.

The combination of Levodopa, Zilingbenacetone, and Dimetotiazine can treat ejaculatory disorders caused by abnormalities in the high Zhongshu (GV7). The degree of libido enhancement is related to the dose size. Administering 5.0g/d of Levodopa can significantly enhance libido or lead to sexual fantasies.

The initial dose is 0.25-0.5g/d, increasing by 0.125-0.5g/d every 3-4 days, with a maintenance treatment dose of 3.0-6.0g/d, taken 4-6 times after meals. Levodopa has many adverse reactions, mainly due to its conversion to dopamine in the body, causing gastrointestinal and cardiovascular system reactions. Therefore, Levodopa must be used under the guidance and supervision of a physician.

6. Deptenyl

Deptenyl is a dopamine agonist, a selective inhibitor of β-type monoamine oxidase, and is considered by experts to be a relatively safe aphrodisiac, especially suitable for elderly patients.

Deptenyl can increase dopamine activity in the brain, making dopamine neurons fully sensitive to physiological and pharmacological stimuli, and correcting the reduced dopamine function in elderly patients. Observations suggest that its side effects are much less than those of Levodopa and Bromocriptine, and it enhances sexual vitality, making it a safer drug.

7. Papaverine

Papaverine is a vasoactive drug, a powerful vascular smooth muscle relaxant. When injected into the corpus cavernosum of the penis, it dilates blood vessels by releasing neurotransmitters and vasoactive intestinal peptides, increasing the inflow of stirred pulse blood into the penis, expanding the cavernous sinus, and reducing venous blood return, thereby increasing the internal pressure of the corpus cavernosum and causing an erection.

Intracavernous injection of Papaverine mainly treats psychogenic impotence. The dose should be determined based on the cause of the disease and the size of the penis. To reduce complications, a constant dose of 30mg is used. If not effective, it can be increased to 60-80mg and used simultaneously with Phentolamine 0.5-2.0mg. The complication of this therapy is priapism, accounting for about 4%. If an erection lasts more than 4 hours, it should be treated promptly. Methods include injecting 15-20ug of adrenaline or 0.8-3.0mg of metaraminol into the corpus cavernosum, or using a corpus cavernosum bloodletting therapy of 20-70ml, both of which can soften and restore the corpus cavernosum.

8. Phentolamine

Phentolamine is a peripheral vasodilator that acts on adrenergic receptors (α-blockers) to relax blood vessels. In the treatment of psychogenic or vascular impotence, it is used in combination with Papaverine to reduce the dose of Papaverine or prevent fibrosis of the corpus cavernosum white membrane caused by long-term use of Papaverine. Additionally, Phentolamine increases the blood flow of stirred pulse in the penis, enhancing the strength of the erection.

The usual dose of Phentolamine is 0.5-2.0mg, and the optimal treatment dose is selected based on the different causes of impotence.

9. Prostaglandin E1 (PGE1)

PGE1 is the most potent vasodilator among prostaglandins, acting directly on the smooth muscle of the corpus cavernosum to induce relaxation and erection, while also antagonizing the effects of norepinephrine to improve penile microcirculation. In addition to its rapid onset and quick disappearance as a drastic purgative, PGE1 has the advantage of aligning with human physiological characteristics, maintaining stability in the body and rarely forming precipitates. As a result, it seldom causes fibrosis of the corpus cavernosum or priapism. However, attention should be paid to pain that occurs during erection.

Yang et al. used PGE1 intracavernosal injection to treat 50 cases of erectile dysfunction, with a dosage of 20ug each time. The results showed that 14 cases (28%) had satisfactory recovery of sexual function, 22 cases (94%) were relatively satisfied, and 19 cases (28%) were ineffective. For the pain during erection, it could be relieved by dissolving 10-20ug of PGE1 in 0.2-0.4ml of 2% procaine solution.

10. Nitroglycerin (Nitroglycerinum)

Nitroglycerin has a good vasodilating effect. In recent years, its cream form has been used to apply to the cavernous body of the penis to treat vascular erectile dysfunction with satisfactory results.

MeyHoff used 10mg of nitroglycerin cream applied to the cavernous body to treat 10 cases of erectile dysfunction, with an average duration of 5 years, all achieving erection effects. Among them, 4 cases had firm erections and successfully completed intercourse, 3 cases replaced papaverine injection therapy, and 3 cases showed significant improvement in erection.

Owen used 2% nitroglycerin ointment applied to the cavernous body to treat 26 cases of erectile dysfunction, among which 25 cases had an average penile length increase of 9.21±1.90mm, and 20 cases underwent ultrasound imaging showing an increase in stirred pulse diameter and a 50% increase in stirred pulse blood flow. Only 1 case experienced hypotension and headache.

Wu Guoming (Wuhan Railway Central Hospital 930064)