Penygra

Penigra contains the component sildenafil, which is its active substance. It selectively slows down the action of the cGMP-specific component of PDE-5.

The physiological process of penile erection development is associated with the release of NO inside the cavernous body due to the impact of a sexual stimulus on it. The NO component helps to activate the enzyme guanylate cyclase, as a result of which the cGMP mark increases, and the smooth muscles of the cavernous body relax with subsequent potentiation of blood flow to them. [ 1 ]

Indications Penygra

It is used by men in case of erectile problems.

Release form

The therapeutic element is released in tablets - 1 or 4 pieces of 50 or 100 mg in volume inside a blister pack. Inside the pack - 1 such package.

Pharmacodynamics

Sildenafil does not demonstrate a direct relaxing effect on the muscles of the cavernous bodies, but it potentiates the effect of NO, slowing down the activity of PDE-5. It should be taken into account that in the absence of a sexual stimulus, sildenafil will have no effect.

Volunteers who took sildenafil once in a 0.1 g dose did not experience clinically significant changes in ECG readings. Its use resulted in a moderate or weak decrease in blood pressure, which did not affect the drug's effectiveness. A more significant decrease in blood pressure was observed in individuals who took the drug together with nitrates. [ 2 ]

Pharmacokinetics

Sildenafil citrate is rapidly absorbed when administered orally, with bioavailability of approximately 40%. The pharmacokinetic parameters of the substance depend on the portion size (within the therapeutic spectrum).

Plasma Cmax values are observed after 0.5-2 hours (on average - 1 hour) after oral administration on an empty stomach. Taking the drug with fatty food causes a decrease in the intensity of absorption, due to which it takes on average 1 hour longer to obtain Cmax.

The average values of the distribution volume (equilibrium) for sildenafil are equal to 105 l.

The element's metabolic processes occur with the participation of liver isoenzymes CYP3A4 (the main route), as well as CYP2C9, after which it is transformed into an active metabolic component N-desmethylsildenafil, which has properties similar to sildenafil. The plasma level of this metabolite is approximately 40% of that recorded for sildenafil. As a result, this element has almost 20% of the therapeutic effect of sildenafil. Both of these components are approximately 96% synthesized with protein.

The half-life of these substances is 4 hours. The systemic clearance of sildenafil is 41 l/hour, and the half-life is 3-5 hours. Sildenafil metabolites are excreted mainly in feces (about 80% of the dose taken orally), and a smaller part in urine (13% of the dose).

Dosing and administration

Penigra is usually taken in a 50 mg dose, approximately 1 hour before sexual intercourse. In general, the permissible range of use before sexual intercourse is 4-0.5 hours. Taking into account the effect and the patient's reaction, the dosage can be increased to the maximum daily (0.1 g) or reduced to the minimum (25 mg).

Taking it with food slows down the effect of the drug compared to taking it on an empty stomach. Also, sexual stimulation is required for the drug to take effect.

Factors that increase the plasma level of the drug: age over 65 years, liver or kidney failure (creatinine clearance level <30 ml per minute), as well as combination with substances that inhibit the action of hemoprotein P4503A4 (including erythromycin with ketoconazole, saquinavir and itraconazole).

Because increased plasma levels may potentiate the drug's effects and side effects, patients with risk factors should initially use a 25 mg dose.

• Application for children

The drug is not used in pediatrics.

Use Penygra during pregnancy

Penigra is not prescribed to women.

Contraindications

Because the drug potentiates the antihypertensive effect of amyl nitrate and other nitrates, it is not prescribed to individuals using these substances or organic nitrates of any type (constantly or according to another regimen).

The medication should not be used if you have an intolerance to any of the ingredients in the tablets.

It is contraindicated for people who should not have sexual intercourse (for example, people with severe stages of cardiovascular pathologies, including severe heart failure and unstable angina).

Side effects Penygra

Side effects often develop when the dosage is increased. These include: dyspepsia, visual disturbances, headaches, increased photosensitivity, epidermal hyperemia, chromatopsia, rash, swelling of the nasal mucosa, dizziness and diarrhea.

In some patients, 60 minutes after taking 0.1 g of the drug, a weak and transient disorder of color perception (associated with green and blue colors) developed, which disappeared after 2 hours.

In flexible dose testing, gastrointestinal disturbances were more common at the 0.1 g dose than at lower doses.

During the post-marketing period, the following single or atypical symptoms were observed upon administration of the drug:

• immune manifestations: signs of intolerance (including epidermal rash);
• lesions associated with the functioning of the cardiovascular system: syncope, tachycardia, decreased blood pressure and nosebleeds;
• problems with digestive function: vomiting;
• visual disturbances: redness or pain in the eye area.

Long-lasting (more than 4 hours) erection, as well as priapism, are observed after using sildenafil only in isolated cases.

Overdose

Testing with volunteers showed that when administering single doses of up to 0.8 g, the incidence of adverse symptoms was similar to that observed with lower doses, but the number of such cases and their severity was higher.

In case of poisoning, standard supportive measures are taken. Renal dialysis procedures do not cause acceleration of drug elimination, because sildenafil is tightly synthesized with plasma protein and is not excreted with urine.

Interactions with other drugs

The administration of sildenafil together with agents that specifically inhibit the action of CYP3A4 (erythromycin and ketoconazole with itraconazole), as well as substances that non-specifically inhibit CYP activity (cimetidine), leads to a decrease in the level of its clearance.

The use of the drug and drugs that induce the action of CYP3A4 (rifampicin) causes a noticeable decrease in plasma levels of the former.

In addition, the plasma level of Cmax of sildenafil increases when combined with saquinavir (it slows down the activity of CYP3A4).

It is prohibited to use in combination with ritonavir, which slows down the effect of P450, because it causes changes in the pharmacokinetics of sildenafil.

Grapefruit juice slightly inhibits the action of CYP3A4 and may therefore slightly increase plasma levels of the drug.

The introduction of 0.1 g of Penigra in combination with amlodipine leads to a decrease in diastolic and systolic pressure values, respectively, by 7 and 8 mm Hg.

AT is reduced in the case of a combination of the drug (in a 25 mg dose) with a substance that blocks the action of α-adrenergic receptors (doxazosin in a 4 mg dose) in individuals with benign prostatic hyperplasia.

Storage conditions

Penigra should be stored in a place closed to small children, at a temperature of maximum 25°C.

Shelf life

Penigra can be used for a period of 36 months from the date of manufacture of the therapeutic agent.

Analogues

Analogues of the drug are Viagra, Lovigra and Superviga with Eroton, as well as Konegra and Viafil.