I. basic information of drugs
1 、Name
-Tadalafil (tadalafil), 5mg is a common dose specification.
2 、Pharmacological action
Tadalafil is a phosphodiesterase 5 (PDE5) inhibitor. PDE5 is mainly found in corpus cavernosum smooth muscle cells. Under sexual stimulation, cavernous nerve endings and endothelial cells release nitric oxide (NO). NO activates guanosine cyclase and increases cyclic guanosine monophosphate (cGMP) synthesis. CGMP relaxes smooth muscle and blood flows into the corpus cavernosum, thus promoting penile erection, while tadalafil inhibits PDE5. Reduce the degradation of cGMP and increase the concentration of cGMP, so as to enhance erectile function.
3 、Applicable disease
-mainly for the treatment of male erectile dysfunction (ED), but also for the treatment of pulmonary hypertension (under different dosage forms and regimens).
4 、Pharmacokinetics
Tadalafil is absorbed rapidly after oral administration. On an empty stomach, it reaches the plasma peak concentration in about 2 hours. Food has a certain effect on its absorption rate, but has no obvious effect on the degree of absorption. Tadalafil has a high plasma protein binding rate, which is mainly metabolized in the liver. Its metabolites are inactive through cytochrome P450 3A4 (CYP3A4) metabolism, mainly excreted in feces in the form of metabolites, and a small amount in urine. Its half-life is longer, about 17.5 hours, which makes it last a long time in vivo.
II. Usage amount
1 、For erectile dysfunction
-for most patients, the initial dose is 10mg before having sex. Depending on the individual's efficacy and tolerance, the dose can be increased to 20mg or reduced to 5mg, while the 5mg dose can also be used as a daily low-dose regimen, taking it at about the same time every day, regardless of when to have sex.
2 、For pulmonary hypertension
-the specific usage and dose are different from those for the treatment of erectile dysfunction. 40mg is usually taken once a day (which may be adjusted under different circumstances) and is used after a detailed assessment of the condition by the doctor, which is strictly distinguished from the use of drugs for the treatment of erectile dysfunction to avoid inappropriate use.
Matters needing attention
1 、Contraindication
-Tadalafil is prohibited in patients who are taking any form of nitrates (such as nitroglycerin, isosorbide dinitrate, etc.) because a combination of the two can lead to severe hypotension.
-it is forbidden for people who are allergic to tadarafi.
2 、Adverse reaction
Common adverse reactions include headache, indigestion, back pain, myalgia, nasal congestion, etc. These adverse reactions are usually mild to moderate and most of them are transient.
-in a few cases, adverse reactions such as visual abnormalities and hearing loss may occur. Although the incidence is low, they should seek medical treatment in time if they occur.
3 、Use by special groups
The elderlyThere is no need to adjust the dose according to age, but the elderly may be more likely to have adverse reactions, which should be used carefully and closely monitored.
Patients with hepatic and renal insufficiencyPatients with mild and moderate renal insufficiency do not need to adjust the dose, but patients with severe renal insufficiency should be cautious and may need to adjust the dose. For patients with mild and moderate hepatic insufficiency, the dose should not exceed 10mg, and it is not recommended for patients with severe hepatic insufficiency.
When using tadalafil 5mg, it must be carried out under the guidance of a doctor to ensure safety and effectiveness.