Description
Latin name
Cialis
Release form
Film-coated tablets.
Packing
In the package 8 pcs.
Pharmacological action of
Pharmacodynamics
Tadalafil is a reversible selective inhibitor of specific type 5 phosphodiesterase (PDE-5) cyclic guanosine monophosphate (cGMP). When sexual arousal causes local release of nitric oxide, inhibition of PDE-5 by tadalafil leads to an increase in the concentration of cGMP in the cavernous body of the penis. The consequence of this is the relaxation of the smooth muscles of the arteries and the flow of blood to the tissues of the penis, which causes an erection.
Tadalafil has no effect in the absence of sexual arousal.
In vitro studies have shown that tadalafil is a selective PDE-5 inhibitor. PDE-5 is an enzyme found in the smooth muscles of the corpus cavernosum, in the smooth muscles of the vessels of internal organs, in skeletal muscles, platelets, kidneys, lungs and cerebellum. The effect of tadalafil on PDE-5 is more active than on other phosphodiesterases.
Tadalafil is 10,000 times more potent with respect to PDE-5 than with PDE-1, PDE-2, PDE-4 and PDE-7, which are localized in the heart, brain, blood vessels, liver, white blood cells, skeletal muscles and in other organs.
Tadalafil blocks PDE-5 10,000 times more actively than PDE-3, an enzyme found in the heart and blood vessels. This selectivity for PDE-5 compared to PDE-3 is important because PDE-3 is an enzyme involved in the contraction of the heart muscle. In addition, tadalafil is about 700 times more active with respect to PDE-5 than with PDE-6, which is found in the retina and is responsible for photo transmission.
Tadalafil also has an effect of 9,000 times more potent for PDE-5 compared to its effect on PDE-8, PDE-9 and PDE-10, and 14 times more potent for PDE-5 compared to PDE-11 .
Tissue distribution and physiological effects of inhibition of PDE-8 – PDE-11 have not yet been clarified.
Tadalafil improves erection and increases the possibility of having a full sexual intercourse.
Tadalafil in healthy individuals does not cause a significant change in systolic and diastolic pressure compared with placebo in the supine position (average maximum decrease is 1.6 / 0.8 mmHg, respectively) and in the standing position (average maximum decrease is 0 , 2 / 4.6 mmHg, respectively). Tadalafil does not cause a significant change in heart rate. Tadalafil does not cause changes in color recognition (blue / green), due to its low affinity for PDE-6. In addition, there is no effect of tadalafil on visual acuity, electrostinogram, intraocular pressure and pupil size.
Several studies have been conducted to evaluate the effect of daily tadalafil on spermatogenesis. None of the studies showed an undesirable effect on sperm morphology and motility. One study found a decrease in mean sperm concentration compared to placebo. A decrease in sperm concentration was associated with a higher frequency of ejaculation. In addition, there was no undesirable effect on the average concentration of sex hormones, testosterone, luteinizing hormone and follicle-stimulating hormone when taking tadalafil compared with placebo.
The efficacy and safety of Cialis ® (at doses of 2.5 mg, 5.0 mg) was studied in clinical trials. An improvement in erection was observed in patients with erectile dysfunction of all degrees of severity when taking tadalafil once a day.
In studies of primary efficacy of 5 mg of tadalafil, 62% and 69% of attempts at sexual intercourse were successful compared to 34% and 39% of patients taking placebo. Taking 5 mg of tadalafil significantly improved erectile function within 24 hours between doses.
Pharmacokinetics
Absorption
After ingestion, tadalafil is rapidly absorbed. The average maximum concentration (Cmax) in plasma is achieved on average 2 hours after ingestion.
The rate and degree of absorption of tadalafil do not depend on the reception, so Cialis ® can be used regardless of the reception.
The time taken (morning or evening) did not have a clinically significant effect on the rate and extent of absorption.
The pharmacokinetics of tadalafil in healthy individuals is linear in time and dose. In the dose range from 2.5 to 20 mg, the area under the concentration-time curve (AUC) increases in proportion to the dose. Equilibrium plasma concentrations are reached within 5 days when taking the drug once a day.
The pharmacokinetics of tadalafil in patients with erectile dysfunction is similar to the pharmacokinetics of the drug in individuals without erectile dysfunction.
Distribution
The average volume of distribution is about 63 L, which indicates that tadalafil is distributed in body tissues. At therapeutic concentrations, 94% of plasma tadalafil binds to proteins. Protein binding does not change with impaired renal function.
In healthy individuals, less than 0.0005% of the administered dose is found in semen.
Metabolism
Tadalafil is mainly metabolized by the isoenzyme CYP3A4 cytochrome P450. The main circulating metabolite is methylcatecholglucuronond. This metabolite is at least 13,000 times less active against PDE-5 than tadalafil. Therefore, the concentration of this metabolite is not clinically significant.
Excretion
In healthy individuals, the average clearance of tadalafil when taken orally is 2.5 l / h, and the average half-life is 17.5 hours. Tadalafil is excreted mainly in the form of inactive metabolites, mainly with feces (about 61% of the dose) and, to a lesser extent, with urine (about 36% of the dose).
Indications
Erectile dysfunction.
Contraindications
Hypersensitivity to tadalafil or to any substance that is part of the drug
In the case of taking drugs containing any organic nitrite
Use in people under 18 years old
Presence of contraindications to sexual activity in patients with diseases of the cardiovascular system: myocardium over the past 90 days, unstable angina, the occurrence of an attack of angina pectoris during intercourse, chronic heart failure II-IV classes according to NYHA classification, uncontrolled arrhythmias, arterial hypotension (blood pressure less than 90/50 mm Hg), uncontrolled arterial hypertension, ischemic stroke over the past 6 months
Loss of vision due to non-arterial anterior ischemic optic neuropathy (regardless of association with the use of PDE-5 inhibitors )
Concomitant use of doxazosin, as well as drugs for the treatment of erectile dysfunction
Often (more than 2 times a week) use in patients with chronic renal failure (creatinine clearance less 30 ml / min)
Lactose deficiency, lactose intolerance, glucose-galactose malabsorption.
Caution
Since no data are available for patients with severe hepatic impairment (Child-Pugh class C), caution must be exercised when prescribing Cialis ® to this patient group
Caution must be exercised when prescribing Cialis ® to patients. taking alpha1-blockers, since the simultaneous use can lead to symptomatic arterial hypotension in some patients.
In a clinical pharmacology study, 18 healthy volunteers who took a single dose of tadalafil did not experience symptomatic arterial hypotension with tamsulosin, an alpha1A-adrenergic blocking agent (see Interaction with other drugs ).
Diagnosis of erectile dysfunction should include the identification of a potential underlying cause, appropriate medical examination and determination of treatment tactics.
Cialis ® should be used with caution in patients with a predisposition to priapism (with sickle cell anemia, multiple myeloma or leukemia) or in patients with anatomical deformation of the penis (angular curvature, cavernous fibrosis or Peyronie’s disease). Caution should also be exercised while taking with powerful inhibitors of the CYP3A4 isoenzyme (ritonavir, saquinavnr, ketoconazole, itraconazole, erythromycin), antihypertensive drugs.
Use during pregnancy and lactation
The drug Cialis ® is not intended for use in women.
Composition of
In 1 film-coated tablet contains:
Tadalafil 20 mg.
Excipients:
Lactose monohydrate
Hyprolose (hydroxypropyl cellulose)
Croscarmellose sodium
Microcrystalline cellulose
Magnesium stearate
Sodium lauryl sulfate, nitrous oxide yellow tritol, nitrite nitrite, yellow tritol nitrate, ldryl sulfate, yellow tritol nitrate, sodium sulfate, nitrite
Dosage and administration
The drug is taken orally. The recommended maximum dose of the drug is 20 mg. The maximum recommended frequency of admission is 1 time / day. Cialis is taken at least 16 minutes before the alleged sexual activity.
Patients may attempt intercourse at any time within 36 hours after taking the drug in order to to establish the optimal response time for taking the drug.
Side effects
Side effects are usually mild or moderate in severity, transient and decrease with continued use of the drug.
Most often: headache (11%), dyspepsia (7%).
Possibly: back pain, myalgia, nasal congestion, flushing of the face.
Rarely: swelling of the eyelids, eye pain, conjunctival hyperemia. dizziness.
Very rare: hypersensitivity reactions (including rashes, hives and swelling of the face, Stevens-Johnson syndrome and exfoliative dermatitis), arterial hypotension (in patients who have already taken antihypertensive drugs), hypertension and syncope, abdominal pain and gastroesophageal reflux, hyperhidrosis (increased sweating), priapism and delayed erection, blurry vision, non-arterial anterior ischemic optic neuropathy, retinal vein occlusion, visual field disturbance.
From the cardiovascular system: in patients with cardiovascular risk factors – myocardial infarction, sudden cardiogenic death, stroke, chest pain, palpitations and tachycardia, however, it is not possible to pinpoint whether these phenomena are directly related to these risk factors, to tadalafil, to sexual arousal, or to a combination of these or other factors.
Drug Interaction
The effect of other drugs on tadalafil
Tadalafil is mainly metabolised by the CYP3A4 isoenzyme. A selective CYP3A4 isoenzyme inhibitor ketoconazole (400 mg per day) increases single dose tadalafil (AUC) exposure by 312% and Cmax by 22%, and ketoconazole (200 mg per day) increased single-dose tadalafil (AUC) exposure by 107% and Cmax by 15% relative to AUC and Cmax values for only one tadalafil.
Ritonavir (200 mg twice daily), an inhibitor of CYP3A4,2C9,2C19 and 2D6 enzymes, increases single dose tadalafil (AUC) exposure by 124% without altering Cmax. Although specific interactions have not been studied, it can be suggested that other HIV protease inhibitors, such as saquinavir, as well as CYP3A4 isoenzyme inhibitors such as erythromycin and intraconazole, increase the activity of tadalafil
. mg per day), reduced single dose tadalafil (AUC) exposure by 88% and Cmax by 46%, relative to AUC and Cmax values for only one tadalafil. We can assume that concomitant administration of other CYP3A4 isoenzyme inducers should also reduce plasma tadalafil concentrations.
Simultaneous administration of antacid (magnesium hydroxide / aluminum hydroxide) and tadalafil reduces the rate of absorption of tadalafil without changing the area under the pharmacokinetic curve for tadalafil.
An increase in gastric pH as a result of intake of H2-histamine receptor blockers of nizatidine had no effect on the pharmacokinetics of tadalafil.
The safety and efficacy of combining tadalafil with other treatments for erectile dysfunction have not been studied, so the use of such combinations is not recommended.
Tadalafil does not potentiate the increase in bleeding time caused by acetylsalicylic acid.
Effects of tadalafil on other drugs
that tadalafil enhances the antihypertensive effect of nitrates. This is due to the additive action of nitrates and tadalafil on the metabolism of nitric oxide II (NO) and cGMP. Therefore, the use of tadalafil against nitrate is contraindicated.
Tadalafil has no clinically significant effect on the clearance of drugs whose metabolism occurs with the participation of cytochrome P450. Studies have confirmed that tadalafil does not inhibit or induce CYP1A2, CYP3A4, CYP2C9, CYP2C19, CYP2D6, CYP2E1 isoenzymes.
Tadalafil has no clinically significant effect on the pharmacokinist of S-warfarin or R-warfarin. Tadalafil does not affect the effect of warfarin on prothrombin time.
Tadalafil does not increase the duration of bleeding caused by acetylsalicylic acid.
Tadalafil has systemic vasodilator properties and can potentiate the effects of antihypertensive drugs aimed at reducing blood pressure.
Additionally, patients who received several antihypertensive agents that had poorly controlled arterial hypertension had a slightly greater decrease in blood pressure. In the vast majority of patients, this decrease was not associated with antihypertensive symptoms. Patients receiving treatment with antihypertensive drugs and receiving tadalafil should be given appropriate clinical recommendations.
No significant decrease in blood pressure was observed when tadalafil was administered by individuals taking the selective tamsulosin alpha1A-blocker.
Concomitant use of tadalafil with doxazosin is contraindicated. When tadalafil was administered to healthy volunteers taking doxazosin (4-8 mg per day), an alpha1-blocker, an increase in the antihypertensive effect of doxazosia was observed. Some patients experienced dizziness. No fainting was observed. The use of doxazosin at lower doses has not been studied.
Tadalafil did not affect the concentration of alcohol, nor did alcohol affect the concentration of tadalafil. At high doses of alcohol (0.7 g / kg) intake of tadalafil did not cause a statistically significant decrease in mean blood pressure. Some patients experienced postural dizziness and orthostatic psoriasis. When taking tadalafil in combination with lower doses of alcohol (0.6 g / kg), no decrease in blood pressure was observed, and dizziness occurred at the same frequency as with single alcohol.
Tadalafil has no clinically relevant effect on the pharmacokinetics or pharmacodynamics of theophylline.
overdose
Symptoms: once administered to healthy volunteers at a dose of 500 mg / day and patients with erectile dysfunction – up to 100 mg / day repeatedly, the undesirable effects were the same as with the drug at lower doses.
Treatment: standard symptomatic therapy. With hemodialysis, tadalafil is virtually eliminated.
Storage conditions
Store at a temperature not higher than 30 ° C.
Expiration
3 years.
The active substance
of tadalafil
Pharmacy
Prescription
dosage form
dosage form
tablets
