Velafax instruction manual
Velafax - an antidepressant. It is used to treat depressive disorders of various origins.
Release form and composition
Velafax is available in the form of tablets of 37.5 mg and 75 mg. Tablets with the instruction are placed in cardboard packing.
The main active ingredient is venlafaxine hydrochloride. 1 tablet contains 42.43 mg of venlafaxine hydrochloride (corresponding to 37.5 mg of venlafaxine) or 84.86 mg of venlafaxine hydrochloride (corresponding to 75 mg of venlafaxine).
Auxiliary components: corn starch, microcrystalline cellulose, talc, carboxymethyl starch sodium, colloidal silicon dioxide, magnesium stearate, iron dye yellow oxide (37.5 mg tablets) or red oxide (75 mg tablets).
Pharmacodynamics. Venlafaxine is an antidepressant. By chemical structure, it can not be attributed to any other class of antidepressants (tricyclic, tetracyclic, and others). The basis of the mechanism of action is the ability of venlafaxine to potentiate the transmission of nerve impulses. The active substance and active metabolite have a pronounced inhibitory effect on the reuptake of serotonin, norepinephrine and a weak inhibitory effect on the reuptake of dopamine. Also, the drug reduces the activity of β-adrenergic receptors both after a single use, and after prolonged therapy.
Venlafaxine does not have an affinity for H-1 histamine receptors, M-cholinergic receptors and α-1 brain adrenergic receptors. Does not inhibit the activity of MAO.
Pharmacokinetics. Venlafaxine is well absorbed from the digestive tract. 2.4 hours after the use of tablets, the maximum concentration of venlafaxine in the blood is reached. If the drug is taken with food, the maximum concentration is reached in 20-30 minutes faster. The value of the maximum concentration and absorption does not change.
Venlafaxine is cleaved in the liver to form the active metabolite, O-desmethylvenlafaxine (EFA). The maximum plasma concentration of EFA is achieved 4.3 hours after taking the pill. 27% of venlafaxine and 30% of EFA are associated with plasma proteins. With repeated use, a steady-state concentration of venlafaxine and a metabolite in plasma is reached for 3 days.
The elimination half-lives of venlafaxine and EFA are, respectively, 5 and 11 hours. The drug is derived in the form of venlafaxine, EFA and inactive metabolites by the kidneys.
Indications for use
Velafax is prescribed for the treatment and prevention of depressions of various nature, including depressive disorders, accompanied by anxiety symptoms.
Velafax is contraindicated:
- with severe functional disorders of the kidneys;
- in severe disorders of the liver;
- during treatment with MAO inhibitors;
- patients with uncontrolled epilepsy;
- during pregnancy and breastfeeding;
- under the age of 18;
- with individual intolerance to the main or one of the auxiliary components of the drug.
Dosing and Administration
Tablets are taken orally during meals, at the same time, washed down with a sufficient amount of liquid.
For the treatment of depressive disorders, Velafax is prescribed in a daily dose of 75 mg (37.5 mg in two doses). If a significant therapeutic effect could not be achieved within a few weeks of therapy, the dose is increased to 150 mg per day (75 mg twice a day).
In severe depressive disorders and conditions that require treatment in a hospital, Velafax can be administered in the initial daily dosage of 150 mg (75 mg in two doses). Every 2-3 days, the dose is increased by 75 mg to achieve a therapeutically significant clinical effect. After this, the dosage can be gradually reduced to the minimum effective level. The maximum allowable daily dosage of Velafax is 375 mg.
For maintenance treatment and prevention of relapse, Velafax is prescribed in the minimum therapeutic dose prescribed at the acute stage. The duration of treatment is 6 months or more.
When using Velafax, undesirable side effects from various body systems can occur:
- on the part of the nervous system - weakness and asthenia, dizziness, insomnia or drowsiness, nightmares, severe nervous irritability, tremors and convulsions , apathy and hallucinations, fainting, speech disorder, imbalance and coordination of movements, delirium and epileptic seizures;
- on the part of the mental state - depression, suicidal behavior (during or after the end of the drug intake);
- on the part of the sense organs - deterioration of visual function, disturbance of accommodation, mydriasis (dilated pupil), ringing / noise in the ears, change in taste perception;
- on the part of the cardiovascular system - hyperemia of the skin, increased blood pressure, arrhythmia, tachycardia , postural hypotension, syncope, ventricular fibrillation;
- on the part of the hematopoietic and lymphatic systems - hemorrhages into the skin (ecchymosis) and mucous membranes, lengthening the duration of bleeding, hemorrhagic syndrome, thrombocytopenia, agranulocytosis, neutropenia, pancytopenia, aplastic anemia;
- respiratory system - shortness of breath, pulmonary eosinophilia;
- on the part of the digestive system - dyspepsia, abdominal pain, dry mouth, nausea and vomiting, constipation, loss of appetite, bruxism, increased activity of liver enzymes, pancreatitis , hepatitis;
- on the part of metabolism - an increase in cholesterol in the blood serum (especially with long-term intake of large doses of the drug), an increase / decrease in weight, inhibition of the production of antidiuretic hormone, hyponatremia, an increase in the content of prolactin;
- on the part of the endocrine system - an increase in the concentration of prolactin, galactorrhea;
- on the part of the musculoskeletal system - muscle spasms, arthralgia, myalgia, rhabdomyolysis;
- on the part of the excretory system - a violation of urination, urinary retention;
- on the part of the reproductive system - erectile dysfunction, decreased libido, menorrhagia, anorgasmia, menstrual disorder in women;
- dermatological reactions - increased sweating, alopecia;
- allergic reactions - skin rash and itching, photosensitization, urticaria , angioedema, erythema multiforme, anaphylactoid reactions.
With prolonged use of the drug, the frequency and severity of side effects occurring decreases. Usually cancel Velafax is not required.
After abrupt discontinuation of Velafax, withdrawal syndrome develops, accompanied by the appearance of marked side effects from the digestive, cardiovascular and nervous systems (nausea and vomiting, anorexia, dry mouth, insomnia, tremor, tachycardia, etc.). To prevent such conditions, it is very important to gradually reduce the dosage of Velafax, especially after taking high doses.
In case of an overdose of Velafax, dizziness, lowering of arterial pressure, changes in electrocardiogram parameters, ventricular or sinus tachycardia / bradycardia, drowsiness, impaired consciousness, even coma, convulsions may occur. More often, severe symptoms of overdose occur while drinking alcohol. At the same time the risk of a lethal outcome is high.
If you exceed the recommended doses, symptomatic treatment is carried out. Requires constant monitoring of electrocardiogram performance, ensuring normal pulmonary ventilation, airway. Due to the threat of aspiration, vomiting is not recommended. There are no specific antidotes for venlafaxine. Hemodialysis is not carried out, since the active substance and the active metabolite are not excreted during dialysis.
During treatment with Velafax, the following points should be taken into account:
- during treatment, there is a likelihood of suicidal attempts, especially in the first days of taking the drug and in the initial stages of recovery, so the patient should be under the constant supervision of a physician until a steady improvement in condition occurs (more often, suicidal behavior is noted in patients under 25 years of age);
- after discontinuation of the drug, the development of withdrawal syndrome is possible, therefore dosages should be reduced gradually over 1 week when taking Velafax in low doses in a short course, and at least 2 weeks when using high doses for a long time;
- patients with affective disorders while taking Velafax may develop a hypomanic or manic condition;
- during treatment, anxiety and anxiety may occur, accompanied by the need for constant movement and the inability to sit / stand in one place; if such symptoms occur, do not increase the dose of Velafax; the drug should be discontinued (if possible);
- during treatment requires constant monitoring of blood pressure, and with long-term therapy - control of cholesterol in serum;
- during therapy, an increase in heart rate may be possible, therefore, the drug is administered with caution to patients with tachycardia;
- during treatment, elderly patients may experience dizziness and imbalance, hyponatremia, and the syndrome of insufficient production of antidiuretic hormone (including while taking diuretics);
- in patients with liver cirrhosis, the concentration of venlafaxine and EFA in plasma increases, the rate of their elimination decreases;
- with mild hepatic insufficiency, dose adjustment of Velafax is not carried out;
- with moderate hepatic insufficiency, the dose is reduced by 50%;
- in case of severe liver failure, the tablets do not apply;
- in mild renal failure, the dosing regimen is not adjusted;
- in moderate renal failure, the half-life of the active ingredient and the active metabolite increases, so the dosage should be reduced by 25–50% (with the entire daily dose taken once);
- in severe renal insufficiency, Velafax is not recommended;
- do not take the drug during hemodialysis;
- pills with caution in half the dosage taken after hemodialysis;
- Elderly patients are prescribed with caution due to the high probability of renal impairment (Velafax is prescribed in the lowest effective dose, while the patient is under constant medical supervision);
- drug withdrawal is carried out gradually - with the use of Velafax in a dose equal to or more than 75 mg in a short course, the dosage is reduced gradually throughout the week, with the use of high doses of the drug for 6 weeks or more, Velafax requires at least 14 days to completely discontinue;
- if, after discontinuation of treatment, the condition worsens and a relapse develops, the initial dosage of tablets is prescribed, and the withdrawal is carried out gradually and longer;
- do not drink alcohol during treatment;
- during treatment, care must be taken when driving vehicles, controlling machinery and performing other activities that require increased concentration and speed of mental and motor responses.
With care, Velafax is prescribed to patients with:
- unstable angina;
- history of seizures;
- controlled epilepsy;
- a history of mania;
- suicidal tendencies;
- increased intraocular pressure;
- angle-closure glaucoma;
- prone to bleeding and skin hemorrhage;
- hyponatremia, dehydration;
- after a recent myocardial infarction;
- diuretic patients;
- patients with low body weight.
- it is impossible to combine reception of Velafaks with MAO inhibitors;
- Velafax can be taken at least 2 weeks after the end of treatment with MAO inhibitors (except for the reversible MAO inhibitor moclobemide, after which Velafax is allowed to drink every other day);
- Reception of MAO inhibitors can be started at least one week after the end of Vellafax;
- when combined with drugs containing lithium, it is possible to increase its concentration in the blood;
- With the combination of Velafax with neuroleptics, symptoms like a malignant neuroleptic syndrome may develop;
- while taking the maximum concentration in the blood and the therapeutic effect of haloperidol increases;
- when combined with Velafax diazepam pharmacodynamics and the effect of both drugs are not changed;
- with simultaneous use with clopamine, the maximum concentration of the latter in the blood increases, and side effects increase (including epileptic seizures);
- do not use alcohol when using Velafax;
- Cimetidine inhibits venlafaxine metabolism without affecting the active metabolite; in elderly patients and patients with impaired liver function, the joint use of these two drugs should be carried out under medical supervision;
- Velafax does not interact with hypoglycemic agents and antihypertensive drugs (β-blockers, diuretics, ACE inhibitors);
- with simultaneous use with warfarin, the anticoagulant effect of the latter increases, the prothrombin time increases;
- the drug can interact with selective serotonin reuptake inhibitors (including triptans), lithium preparations, therefore, with their simultaneous use, caution is required;
- Velafax cannot be combined with weight loss drugs (there is no clinical safety data).
Pregnancy and lactation
Velafax is not used during pregnancy, because the safety of use of the drug in pregnant women has not been studied.
Venlafaxine and the active metabolite are excreted in breast milk. The safety of these compounds for infants has not been established, so if you need to use Velafax, you should stop feeding for the period of treatment.
The complete structural analogs of Velafax, containing the same active ingredient, are the drugs: Efectin, Velaksin, Venlaksor, Efevelon.
Terms and conditions of storage
Velafax is stored protected from sunlight and moisture, out of the reach of children, at a temperature below 25 ° C. Shelf life is 3 years. Do not take pills after the expiration date indicated on the package.
Velafax tablets 37.5 mg, 28pcs. - 520-600 rubles.
Velafax tablets 75mg, 28pcs. - 710-770 rub.