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Zieden
Zidena is a medicine that improves erectile function.
Pharmacodynamics
The active component of udenafil is a selective inhibitor of a specific element of PDE-5 (reversible action), which helps the cGMP exchange process.
Udenafil does not have a direct relaxing effect on the isolated cavernous body, although under the influence of sexual stimulation it increases the relaxing effect of nitric oxide (by slowing down PDE-5 responsible for the destruction of cGMP inside the cavernous body).
As a result, the smooth muscles of the arteries relax, and the blood flows to the tissues inside the penis, stimulating the erection. If sexual stimulation is not available, the medicine will not have the desired effect.
In vitro tests demonstrated that udenafil acts as a selective inhibitor of the enzyme PDE-5. This element is located inside the smooth muscles of the cavernous body, and with it the vessels of the organs, and in addition to the musculature of the skeleton, the kidneys with platelets, as well as the cerebellum with the lungs. Udenafil inhibits the element of PDE-5 more than 10,000 times faster than enzymes PDE-1 and PDE-2, as well as FDE-3 with PDE-4, located inside the brain with the heart and liver, and in addition blood vessels and other organs.
Along with this, the acting component is 700 times more potent on PDE-5 than on the element of PDE-6 (it is in the retina, responsible for the perception of colors). Udenafil does not slow down the activity of PDE-11, as a result of which it does not cause muscle and lumbar pains, as well as signs of testicular toxicity.
Thanks to the active substance improves the erection, which contributes to the successful implementation of sexual intercourse.
The drug lasts up to 24 hours. It begins to manifest itself after half an hour after admission (under the condition of sexual arousal in a man).
In healthy men, the active component does not provoke a significant change in the values of the SAD, as well as the DAD with respect to the placebo in the recumbent and standing positions (the maximum lowered level averages 1.6 / 0.8, and 0.2 / 4.6 mm Hg, respectively. St.).
Together with this, udenafil does not change the color perception (green / blue), since it has a weak affinity for the element of PDE-6. The substance does not affect the indices of pressure inside the eyes, visual acuity, and at the same time the size of the pupils and ERG.
During the testing of udenafil, there was no clinically significant effect on the concentration index, and at the same time the amount of sperm released, and in addition morphology along with the motility of the spermatozoa.
Pharmacokinetics
The medicine is quickly absorbed after internal use. The peak of the plasma index comes after 0.5-1.5 hours (on the average 1 hour).
The half-life is 12 hours, and the high synthesis of the substance with the plasma protein (93.9%) prolongs the period of its exposure to 24 hours with the use of a single dose.
Eating foods that contain large amounts of fat does not affect the absorption index of udenafil. The pharmacokinetic properties of drugs are also not affected by simultaneous oral administration of the drug in the amount of 200 mg and alcohol at a dosage of 112 ml (recalculation with 40% ethyl alcohol).
Metabolism is most often carried out with the participation of isoenzyme CYP3A4 hemoprotein P450.
The overall level of the component's cleansing factor in a healthy person is 755 ml / minute. After oral administration, it is excreted in the form of decay products along with feces.
The active ingredient does not accumulate in the body. With daily use of drugs, volunteers in the amount of 100 and 200 mg in the period of 10 days showed no noticeable changes in the pharmacokinetics of the drug.
Contraindications
Among the contraindications of drugs:
- intolerance to any of the elements of the drug;
- combined use together with nitrates and other suppliers of nitric oxide;
- children age less than 18 years.
Caution is required when appointing in such cases:
- men with uncontrolled increase in blood pressure (more than 170/100 mm Hg), as well as a decrease in blood pressure (less than 90/50 mm Hg);
- people with a hereditary form of degenerative retinal pathologies (among them pigment retinitis, as well as proliferative DRP);
- Persons who have suffered myocardial infarction, stroke, or coronary artery bypass in the last six months;
- if the patient has kidney failure or liver in severe form;
- with congenital syndrome UIQT or lengthening of this indicator due to the use of drugs;
- predisposition to the development of priapism;
- men with an anatomically deformed penis;
- patients who have an implant in the penis;
- people with CCC pathologies - an unstable form of angina pectoris or with angina pectoris, which appears during sexual intercourse; a chronic form of heart failure (II-IV functional class according to the NYHA classification), which developed in the patient over the last six months; and in addition to uncontrolled heart rhythm disorders: in such cases, it is necessary to take into account the possibility of complications;
- combined admission with α-adrenoblockers, CCB or other antihypertensive drugs, as this may cause an additional decrease in DAD, and also a SAD of 7-8 mm Hg.
Side effects of the zieden
Due to the use of drugs it is possible to develop such side effects:
- CAS organs: often there is a rush of blood to the skin of the face;
- organs of the central nervous system: in some cases dizziness, paresthesia or cervical radiculitis develops;
- visual organs: often reddening of the eyes, in more rare cases, there are pain, blurred vision or increased lachrymation;
- skin: in some cases develop hives, there is swelling on the face or eyelids;
- organs of the digestive system: mainly develop discomfort in the stomach or dyspepsia; less often there are toothaches or nausea, gastritis or constipation develops;
- organs of the respiratory system: usually there is a stuffy nose, and occasionally develops dyspnea or dryness of the nasal mucosa;
- organs of ODA: periarthritis develops singly;
- general: often there is an uncomfortable sensation in the sternum or headache, and besides this fever; There are single abdominal pains, pain in the sternum, a feeling of thirst or fatigue.
During the post-marketing testing of drugs, other negative manifestations were also described: rapid heartbeat, nose blood, diarrhea, tinnitus, allergy (erythema and skin rash), prolonged erection, sensation of noticeable general discomfort, and other than cold or heat, and also cough and positional dizziness.
Dosing and administration
The medicine is taken orally, regardless of food. A dosage of 100 mg is recommended. The tablet should be taken half an hour before the alleged sexual intercourse.
Given the individual reaction to the drug, as well as its effectiveness, the dosage may be increased to 200 mg.
For a day, the drug can be taken no more than 1 time.
Overdose
In the case of a drug use of 400 mg, the side effect was comparable to the symptoms that were observed with the use of the drug in smaller doses, but they were more frequent.
To eliminate the overdose, therapy should be applied to get rid of the symptoms. The dialysis procedure does not accelerate the excretion of the active component of the drug.
Interactions with other drugs
Inhibitors of isoenzyme of hemoprotein P450 CYP3A4 (such as indinavir with ritonavir, erythromycin with cimetidine, and also itraconazole with ketoconazole and grapefruit juice) are capable of increasing the properties of udenafil.
Ketoconazole (at a dosage of 400 mg) increases the plasma peak and bioavailability of udenafil (at a dosage of 100 mg), 0.8 times (or 85%), and almost twice (or 212%), respectively.
Ritonavir and indinavir significantly increase the properties of udenafil.
Rifampin, dexamethasone, as well as anticonvulsants (such as phenytoin with carbamazepine and phenobarbital) are able to accelerate the metabolism of udenafil, resulting in the combined use of these drugs weakened.
With the combined use of udenafil (with oral administration at a dosage of 30 mg / kg) with nitroglycerin (a single intravenous injection of 2.5 mg / kg) under experimental testing conditions, there was no effect on the pharmacokinetic properties of udenafil, but combining them is still not recommended, since this can lower the blood pressure level.
Udenafil, as well as drugs that are part of the category of α-blockers are vasodilators, therefore, in case of simultaneous use, they should be prescribed in minimal dosages.