Tadalafil: PDE5 Inhibitor for Male Erectile Dysfunction
Gui í a de Salud Masculina
- I. the mechanism of action
- II. Characteristics of drugs
- Usage and dosage
- IV. Adverse reactions
- V. matters needing attention
Tadalafil (tadalafil) is a drug for the treatment of male erectile dysfunction (ED). Here are some details:
I. the mechanism of action
1 、Effect on corpus cavernosum smooth muscle of penis
Tadalafil is a phosphodiesterase 5 (PDE5) inhibitor. During sexual stimulation, the nerve endings of the corpus cavernosum release nitric oxide (NO). NO activates guanylate cyclase and increases the synthesis of cyclic guanosine monophosphate (cGMP).
-cGMP can relax the smooth muscle of the corpus cavernosum and blood flows into the penile tissue, thus promoting penile erection, while PDE5 can decompose cGMP and reduce its concentration. Tadalafil can inhibit PDE5, reduce the degradation of cGMP, maintain the level of cGMP in the sponge, and contribute to penile erection and maintenance of erection.
II. Characteristics of drugs
1 、Long-term effect
-compared with other similar drugs, tadalafil has a longer action time and a half-life of about 17.5 hours. after a single dose, the effective concentration in the body can be maintained for a longer time, and it may still improve erectile function within 36 hours after taking it. this provides patients with a more flexible schedule of sexual life.
2 、Validity
In many clinical trials, tadalafil has been shown to be effective in the treatment of erectile dysfunction caused by different causes. Whether it is ED caused by vascular, neurotic or endocrine factors, tadalafil can improve the erectile function of patients to some extent and improve the quality of sexual life.
Usage and dosage
1 、Conventional usage
For erectile dysfunction, the initial dose is recommended as 10mg, which can be increased to 20mg or reduced to 5mg, depending on the efficacy and tolerance of the individual.
The use of tadalafil is not affected by eating, which is different from some other drugs that need to be taken on an empty stomach, which increases the convenience of patients.
2 、Usage of special population
-for elderly patients (over 65 years old), it is generally not necessary to adjust the initial dose, but it should be assessed on the basis of individual responses.
-patients with mild or moderate renal insufficiency (creatinine clearance rate of 30-80ml/min) do not need to adjust the dose, and patients with severe renal insufficiency (creatinine clearance rate-lt;30ml/min), the maximum recommended dose is 5mg.
-for patients with mild or moderate liver insufficiency (Child-Pugh grade An or B), the recommended dose is 10mg, while it is not recommended for patients with severe liver insufficiency (Child-Pugh grade C).
IV. Adverse reactions
1 、Common adverse reactions
Headache is one of the more common adverse reactions, and its incidence is relatively high, which may be related to the effect of drugs on vasodilation, because tadalafil plays a role by regulating the signal pathway in blood vessels. While improving the blood flow of the corpus cavernosum, it may also affect some physiological states of blood vessels in the brain.
-dyspepsia, back pain and myalgia are also common. Most of these adverse reactions are mild to moderate and can usually be relieved gradually after drug withdrawal.
2 、Rare but serious adverse reactions
-sudden vision loss or loss may occur, although this is very rare, if the patient has vision problems in the course of medication, he should stop the medication immediately and seek medical attention, this may be related to the potential effects of tadalafil on the blood vessels or nerves of the eyes.
-A very small number of cases of hearing loss or loss have been reported, which require attention.
V. matters needing attention
1 、Interaction with other drugs
Tadalafil cannot be used in conjunction with organic nitrates (such as nitroglycerin, isosorbide dinitrate, etc.) because both drugs have vasodilation, which can lead to severe hypotension and even life-threatening.
-caution should be taken when used with alpha-blockers (such as tamsulosin). It may be necessary to adjust the drug dose and closely monitor the patient's blood pressure, as the simultaneous use of these two types of drugs may also increase the risk of hypotension.
2 、Use by special groups
-Tadalafil should not be used by women and children because the drug is specifically developed for male erectile dysfunction and there is no data on safety and efficacy in women and children.
-before using tadalafil, patients should inform the doctor of their health status, including cardiovascular disease, hypotension, liver or kidney disease, etc., so that the doctor can accurately assess the safety and effectiveness of the drug.