Velafax user guide
Velafax is an antidepressant. It is used to treat depressive disorders of various origins.
Form of issue and composition
Velafax is available in the form of tablets of 37.5 mg and 75 mg. Tablets with instructions are placed in cardboard packaging.
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, sodium carboxymethyl starch, colloidal silicon dioxide, magnesium stearate, iron dye yellow oxide (37.5 mg tablets) or red oxide (75 mg tablets).
Pharmacodynamics. Venlafaxine is an antidepressant. According to its chemical structure, it can not be assigned to any other class of antidepressants (tricyclic, tetracyclic and others). The mechanism of action is based on the ability of venlafaxine to potentiate the transmission of a nerve impulse. The active substance and the active metabolite exert 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 application, and after prolonged therapy.
Venlafaxine does not have an affinity for H-1 histamine receptors, M-cholinergic receptors and α-1 adrenergic receptors of the brain. MAO activity is not depressing.
Pharmacokinetics. Venlafaxine is well absorbed from the digestive tract. 2.4 hours after the application of the tablets, the maximum concentration of venlafaxine in the blood is reached. If the drug is taken with food, the maximum concentration is reached 20-30 minutes faster. The maximum concentration and absorption do not change.
Venlafaxine is cleaved in the liver with the formation of an active metabolite - O-desmethylvenlafaxine (EFA). The maximum plasma concentration of EFA is reached 4.3 hours after taking the tablet. 27% of venlafaxine and 30% of EFA are associated with plasma proteins. With repeated use, a stable concentration of venlafaxine and metabolite in the plasma is achieved for 3 days.
The half-lives of venlafaxine and EFA are, respectively, 5 and 11 hours. The drug is withdrawn in the form of venlafaxine, EFA and inactive metabolites by the kidneys.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 symptoms of anxiety.
Velafax is contraindicated:
- With severe functional impairment of kidney function;
- With severe violations of the liver;
- During treatment with MAO inhibitors;
- Patients with uncontrolled epilepsy;
- During pregnancy and breastfeeding;
- Under the age of 18;
- With individual intolerance of the main or one of the auxiliary components of the drug.
Dosing and Administration
Tablets are taken orally during a meal, at the same time, washed down with a sufficient amount of liquid.
To treat depressive disorders, Velafax is prescribed in a daily dose of 75 mg (37.5 mg in two divided doses). If a significant therapeutic effect is not achieved within a few weeks of therapy, the dose rises to 150 mg per day (75 mg twice daily).
In severe depressive disorders and conditions requiring hospital treatment, Velafax can be administered at an initial daily dosage of 150 mg (75 mg in two divided doses). Every 2-3 days, the dose is increased by 75 mg to achieve a therapeutically significant clinical effect. After that, the dosage can gradually decrease to a minimum effective level. The maximum allowable daily dosage of Velafax is 375 mg.
For maintenance treatment and prevention of relapses, Velafax is prescribed in the minimum therapeutic dose administered at the acute stage. Duration of treatment is 6 months or more.
When using Velafax, unwanted side effects from various body systems may occur:
- From the nervous system - weakness and asthenia, dizziness, insomnia or drowsiness, nightmares, pronounced nervous excitability, tremors and convulsions , apathy and hallucinations, fainting, speech disorders, imbalance and coordination of movements, delirium and epileptic seizures;
- From the mental state - depression, suicidal behavior (during or after the end of the drug);
- From the sense organs - impairment of visual function, disruption of accommodation, mydriasis (dilated pupil), ringing / noise in the ears, change in taste perception;
- From the side of the cardiovascular system - hyperemia of the skin, increased blood pressure, arrhythmia, tachycardia , postural hypotension, syncope, ventricular fibrillation;
- From the hemopoietic and lymphatic systems - hemorrhages in the skin (ecchymoses) and mucous membranes, lengthening of bleeding time, hemorrhagic syndrome, thrombocytopenia, agranulocytosis, neutropenia, pancytopenia, aplastic anemia;
- From the respiratory system - shortness of breath, pulmonary eosinophilia;
- On the part of the digestive system - dyspepsia, abdominal pain, dry mouth, nausea and vomiting, constipation, impaired appetite, bruxism, increased activity of hepatic enzymes, pancreatitis , hepatitis;
- From the side of metabolism - increase in serum cholesterol (especially with prolonged intake of large doses of the drug), weight gain / decrease, suppression of antidiuretic hormone production, hyponatremia, prolactin increase;
- On the part of the endocrine system - an increase in the concentration of prolactin, galactorrhea;
- From the musculoskeletal system - muscle spasms, arthralgia, myalgia, rhabdomyolysis;
- On the part of the excretory system - violation of urination, urinary retention;
- On the part of the reproductive system - erectile dysfunction, decreased libido, menorrhagia, anorgasmia, menstrual cycle disorders in women;
- Dermatological reactions - increased sweating, alopecia;
- Allergic reactions - skin rash and itching, photosensitivity, urticaria , angioedema, erythema multiforme, anaphylactoid reactions.
With prolonged use of the drug, the frequency and severity of the resulting side effects is reduced. Usually, the cancellation of Velafax is not required.
After the abrupt discontinuation of admission, Velafax develops withdrawal syndrome, which is accompanied by the emergence of severe 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, low blood pressure, changes in the electrocardiogram index, ventricular or sinus tachycardia / bradycardia, drowsiness, impaired consciousness, up to coma, convulsions may occur. Often, severe overdose symptoms occur with the simultaneous use of alcoholic beverages. At the same time, the risk of death is high.
When the recommended doses are exceeded, symptomatic treatment is performed. It requires constant monitoring of electrocardiogram parameters, maintenance of normal pulmonary ventilation, patency of the respiratory tract. Because of the threat of aspiration, it is not recommended to induce vomiting. There are no specific antidotes to venlafaxine. Hemodialysis is not performed, since the active substance and active metabolite are not withdrawn during dialysis.
During treatment with Velafax, the following points should be taken into account:
- During treatment, there is a possibility of suicide attempts, especially in the first days of taking the drug and at the initial stages of recovery, so the patient should be under constant medical supervision until a stable improvement in the condition occurs (suicidal behavior is usually observed in patients under 25 years old);
- After the withdrawal of the drug may develop withdrawal syndrome, so dosage should be reduced gradually for 1 week with the admission of Velafax in low doses a short course, and at least 2 weeks with high doses for a long time;
- In patients with affective disorders, adherence to Velafax may develop a hypomanic or manic condition;
- During the treatment there can be a state of anxiety and anxiety, accompanied by the need for constant movement and the inability to sit / stand in one place; If such symptoms do not increase the dose of Velafax, you should cancel the drug (if possible);
- During treatment, a constant control of blood pressure is required, and with prolonged therapy, control of the cholesterol content in the blood serum;
- On the background of therapy, it is possible to increase the heart rate, so the drug is administered with caution to patients with tachycardia;
- On the background of treatment in elderly patients, dizziness and imbalance, hyponatremia and a syndrome of insufficient production of antidiuretic hormone (including with the simultaneous administration of diuretics) may occur;
- In patients with cirrhosis of the liver, the concentration of venlafaxine and EFA in blood plasma increases, the rate of their elimination decreases;
- With mild hepatic insufficiency correction of doses of Velafax is not carried out;
- With moderate hepatic insufficiency, the dose is reduced by 50%;
- In severe hepatic insufficiency, tablets are not used;
- With mild renal failure, the dosing regimen is not corrected;
- With moderate renal failure, the half-life of the active substance and the active metabolite increases, so the dosage should be reduced by 25-50% (with the whole daily dose taken once);
- With severe renal failure, Velafax is not recommended;
- Do not take the drug during hemodialysis;
- With care, tablets in a twice-reduced dosage are taken after the end of hemodialysis;
- Elderly patients the drug is administered with caution because of the high probability of disrupting the kidneys (Velafax is prescribed in the lowest effective dose, with the patient under constant medical supervision);
- The drug is withdrawn gradually - when Velafax is applied at a dose equal to or greater than 75 mg in a short course, the dosage is gradually reduced throughout the week, when using high doses of the drug for 6 or more weeks, a total refusal of Velafax requires a minimum of 14 days;
- If after the cessation of treatment the condition worsens and a relapse develops, the initial dosage of tablets is prescribed, and the abolition is carried out gradually and more dura- tionally;
- It is not possible to drink alcohol during treatment;
- During treatment, care must be taken when transporting people, managing mechanisms and carrying out other activities that require increased concentration of attention and speed of mental and motor reactions.
With caution, Velafax is prescribed to patients with:
- Unstable angina;
- Arterial hypertension;
- A convulsive syndrome in the anamnesis;
- Controlled by epilepsy;
- A manic condition in the anamnesis;
- Suicidal tendencies;
- Increased intraocular pressure;
- Angle-closure glaucoma;
- Tendency to bleeding and skin hemorrhages;
- Hyponatremia, dehydration;
- After a recent myocardial infarction;
- Patients taking diuretics;
- Patients with low body weight.
- It is impossible to combine the reception of Velafax with MAO inhibitors;
- Velafax can be started 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 after a day);
- Taking MAO inhibitors can begin at least one week after the end of the reception of Velafax;
- When combined with preparations containing lithium, it is possible to increase its concentration in the blood;
- When the combination of Velafax with neuroleptics may develop symptoms similar to malignant neuroleptic syndrome;
- With simultaneous admission, the maximum concentration in the blood and the therapeutic effect of haloperidol increase;
- When Velafax is combined with diazepam, pharmacodynamics and the effect of both drugs do not change;
- With simultaneous use with clopamine, the maximum concentration of the latter in the blood rises, and the side effects are amplified (including epileptic seizures);
- It is impossible to drink liquor when using Velafax;
- Cimetidine suppresses the metabolism of venlafaxine, without affecting the active metabolite; In elderly patients and patients with hepatic impairment, the joint application of these two drugs should be performed under the supervision of a physician;
- Velafax does not interact with hypoglycemic agents and antihypertensive drugs (β-adrenoblockers, diuretics, ACE inhibitors);
- When used simultaneously with warfarin, the anticoagulant effect of the latter is enhanced, the prothrombin time increases;
- The drug can interact with selective serotonin reuptake inhibitors (including triptans), lithium preparations, so caution is required when using them simultaneously;
- It is impossible to combine Velafax with drugs to reduce body weight (no clinical safety data).
Pregnancy and lactemia
Velafax is not used during pregnancy, since the safety of the use of the drug in pregnant women has not been studied.
Venlafaxine and an active metabolite are excreted in breast milk. The safety of these compounds for infants is not established, so if you need to use Velafax, you should stop feeding for the period of treatment.
The complete structural analogues of Velafax containing the same active substance are preparations: Efektin, Velaxin, Venlaksor, Efewelon.
Terms and conditions of storage
Velafax is stored in a place protected from sunlight and moisture, inaccessible to children, at a temperature below 25 ° C. Shelf life is 3 years. Do not take the pill after the expiration date indicated on the package.
Velafax tablets 37.5 mg, 28pcs. - 520-600 rub.
Velafax tablets 75mg, 28pcs. - 710-770 rub.