Velafax®
MAO inhibitors
Irreversible non-selective MAO inhibitors
Venlafaxine should not be taken in combination with irreversible, non-selective MAO inhibitors, and the interval between discontinuation of MAO inhibitor therapy and initiation of venlafaxine therapy should be at least 14 days. Venlafaxine therapy must be discontinued no later than 7 days before starting therapy with MAO inhibitors.
Reversible selective MAO inhibitors (moclobemide)
Due to the risk of developing serotonin syndrome, the combination of venlafaxine with reversible and selective MAO inhibitors such as moclobemide is not recommended. After treatment with reversible MAO inhibitors, an interval of less than 14 days may be allowed before starting venlafaxine therapy. It is recommended to discontinue venlafaxine therapy at least 7 days before starting therapy with reversible MAO inhibitors.
Reversible non-selective MAO inhibitors (linezolid)
The antibiotic linezolid is a weakly reversible and non-selective MAO inhibitor and should not be prescribed to patients taking venlafaxine.
Serious adverse reactions have been reported in patients who stopped MAO inhibitor therapy shortly before starting venlafaxine and in those who started a course of MAO inhibitors immediately after a course of venlafaxine. These side effects included tremor, myoclonus, diaphoresis, nausea, vomiting, flushing with a feeling of heat, dizziness and pyrexia with symptoms similar to those of neuroleptic malignant syndrome, as well as seizures and death.
Serotonin syndrome
Venlafaxine may affect the pharmacodynamics of other drugs acting at the level of the serotonergic neurotransmitter system, so caution should be exercised when co-administering it with triptans, other selective serotonin reuptake inhibitors and lithium preparations.
During concomitant treatment with venlafaxine and selective serotonin reuptake inhibitors (SSRIs), serotonin norepinephrine reuptake inhibitors (SNRIs) or serotonin receptor antagonists, it is recommended to carefully monitor the patient, especially at the beginning of therapy and when increasing the dose of the drug.
Concomitant use of venlafaxine with serotonin precursors, such as dietary supplements containing tryptophan, is not recommended.
Drugs acting on the central nervous system (CNS)
The risk of using venlafaxine in combination with other drugs acting on the central nervous system has not been studied. Caution should be exercised during therapy with venlafaxine in combination with other drugs acting on the central nervous system.
Ethanol
Concomitant use of ethanol and venlafaxine was not accompanied by a decrease in mental and motor activity. Despite this (as in the case of taking other drugs that affect the central nervous system), the use of ethanol is not recommended during venlafaxine therapy.
Drugs that prolong the QT interval
When venlafaxine is used concomitantly with other drugs that prolong the QT interval, the risk of QT prolongation and/or ventricular arrhythmias increases. The combined use of these drugs should be avoided.
Drugs that prolong the QT interval include:
- class 1a and III antiarrhythmic drugs (for example, quinidine, amiodarone, sotalol, dofetilide);
- some antipsychotics (for example, thioridazine);
- some macrolide antibiotics (for example, erythromycin);
- some antihistamines;
- some quinolone antibiotics (for example, moxifloxacin).
This list is not exhaustive, so other drugs known to significantly prolong the QT interval should be avoided.
The influence of other drugs on the effects of venlafaxine
Ketoconazole
(CYP3A4 inhibitor) A pharmacokinetic study with ketoconazole in extensive and poor metabolizers of CYP2D6 showed a higher area under the curve for venlafaxine (70% and 21% in poor and extensive metabolizers, respectively) and O-desmethylvenlafaxine (ODV) (33% and 23% in slow and rapid metabolizers, respectively) after taking ketoconazole.
Concomitant use of CYP3A4 inhibitors (eg, atazanavir, clarithromycin, indinavir, itraconazole, voriconazole, posaconazole, ketoconazole, nelfinavir, ritonavir, saquinavir, telithromycin) and venlafaxine may increase blood levels of venlafaxine and EDV. Caution is recommended if the patient's therapy includes concomitant use of CYP3A4 inhibitors and venlafaxine.
The effect of venlafaxine on other medications
Drugs metabolized by cytochrome P450 isoenzymes
In vivo studies
indicate that venlafaxine is a relatively weak inhibitor of CYP2D6.
Venlafaxine did not inhibit CYP3A4 (alprazolam and carbamazepine), CYP1A2 (caffeine) and CYP2C9 (tolbutamide) or CYP2C19 (diazepam) in vivo.
Lithium
When venlafaxine is used concomitantly with lithium preparations, the level of lithium in the blood may increase, which can cause potentially life-threatening serotonin syndrome.
Diazepam
When used simultaneously with diazepam, the pharmacokinetics of the drugs and their main metabolites do not change significantly.
Imipramine
When used simultaneously with imipramine, the pharmacokinetics of venlafaxine and its metabolite EDV do not change. Venlafaxine does not affect the metabolism of imipramine and its metabolite 2-hydroxyimipramine, but increases the area under the pharmacokinetic curve and maximum plasma concentrations of desipramine (the main metabolite of imipramine), and also reduces the renal clearance of 2-hydroxydesipramine. The clinical significance of this phenomenon is unknown. Caution should be exercised when co-administering venlafaxine with imipramine.
Haloperidol
Venlafaxine reduces the renal clearance of haloperidol by 42%, while the area under the pharmacokinetic curve and Cmax increase by 70% and 88%, respectively. The effects of haloperidol may be enhanced.
Risperidone
When used simultaneously with risperidone, despite an increase in the area under the pharmacokinetic curve of the drug, the pharmacokinetics of the sum of the active components (risperidone and its active metabolite) did not change significantly.
Metoprolol
Coadministration of venlafaxine and metoprolol to healthy volunteers in a pharmacokinetic interaction study of the two drugs resulted in an increase in plasma concentrations of metoprolol by 30-40% without changes in the concentration of its active metabolite α-hydroxymetoprolol. The clinical significance of this result in patients with hypertension is unknown. Metoprolol did not change the pharmacokinetic profile of venlafaxine or its active metabolite EDV. Caution should be exercised when taking venlafaxine and metoprolol together.
Indinavir
When taken simultaneously with indinavir, there is a decrease in the area under the pharmacokinetic curve of indinavir by 28% and a decrease in its maximum concentration in blood plasma by 36%, while the pharmacokinetic parameters of venlafaxine and EDV do not change. The clinical significance of this effect is unknown.
Oral contraceptives
During post-marketing experience, unintended pregnancies have been reported in patients taking oral contraceptives during treatment with venlafaxine. There is no convincing evidence that these pregnancies were the result of drug interactions with venlafaxine. Interaction studies with hormonal contraceptives have not been conducted.
Warfarin
When used simultaneously with warfarin, the anticoagulant effect of the latter may be enhanced, while prothrombin time, expressed through INR (international normalized ratio), is prolonged.
Cimetidine
Cimetidine suppresses the metabolism of venlafaxine during the “first pass” through the liver and has no effect on the pharmacokinetics of EDV. In most patients, only a slight increase in the pharmacological activity of venlafaxine and EDV is expected (more pronounced in elderly patients and with impaired liver function). In elderly patients and in patients with impaired liver function, the simultaneous use of cimetidine and venlafaxine should be carried out under medical supervision.
Antihypertensive and hypoglycemic drugs
No clinically significant interaction of venlafaxine with antihypertensive (including beta-blockers, angiotensin-converting enzyme inhibitors and diuretics) and hypoglycemic drugs was found.
A potential interaction between venlafaxine and drugs that inhibit the activity of the CYP2D6 isoenzyme cannot be excluded. Caution should be exercised when using Velafax® simultaneously with these drugs (for example, quinidine, paroxetine, fluoxetine, fluvoxamine, perphenazine, haloperidol, levomepromazine).
Instructions for use VELAFAX
1. Suicide/suicidal ideation or clinical deterioration
All patients need to determine the risk of suicide and monitor possible deterioration of the clinical condition.
Depression increases the risk of suicidal thoughts and suicide attempts. This risk persists until stable remission occurs. Therefore, patients should be under constant medical supervision and should be given only small quantities of the drug capsules to reduce the risk of possible abuse and/or overdose.
Psychiatric disorders for which venlafaxine is prescribed may also be associated with an increased risk of suicide. In addition, these disorders may be comorbid with major depressive illness. The precautions required when treating patients with major depressive disorder should be observed when treating patients with other mental disorders.
Patients with a history of suicidal events or those who have experienced severe suicidal ideation prior to treatment are known to be at greater risk for suicidal ideation or suicide attempts and should undergo therapy with closer monitoring. A meta-analysis of placebo-controlled clinical trials of antidepressants in adult patients with mental disorders showed an increased risk of suicidal behavior with antidepressants compared with placebo in patients younger than 25 years.
Drug therapy, especially at the beginning of treatment and after dosage changes, should be accompanied by careful monitoring of patients, especially high-risk patients. Patients (and medical personnel) should be warned to monitor for any clinical deterioration, suicidal behavior or thoughts, unusual changes in behavior, and seek immediate medical attention if such symptoms occur.
Use in children and adolescents under 18 years of age.
Venlafaxine should not be used to treat children and adolescents under 18 years of age. Suicidal behavior (suicide attempts and suicidal ideation) and hostility
(mainly aggression, disruptive behavior and anger) were observed more frequently in clinical trials among children and adolescents treated with antidepressants compared with placebo. If, based on clinical needs, a decision about therapy is made, the patient should be carefully assessed for the emergence of suicidal symptoms. In addition, long-term safety data in children and adolescents regarding growth, maturation, changes in consciousness, and behavioral responses are lacking.
2. Serotonin syndrome
As with other serotonergic agents, serotonin syndrome, a potentially life-threatening condition, can occur with venlafaxine therapy, especially with concomitant use of other agents such as MAO inhibitors, which can affect serotonergic neurotransmitters.
Symptoms of serotonin syndrome:
- mental status changes (eg, agitation, hallucinations, coma), autonomic nervous system disorders (eg, tachycardia, labile blood pressure, hyperthermia), neuromuscular aberrations (eg, hyperreflexia, incoordination), and/or gastrointestinal disorders (eg , nausea, vomiting, diarrhea).
3. Angle-closure glaucoma
Cases of mydriasis have been reported while taking venlafaxine, so patients with a predisposition to increased intraocular pressure or at risk of angle-closure glaucoma require careful medical monitoring.
4. Blood pressure
Dose-dependent increases in blood pressure have been reported with venlafaxine use. In some cases, in post-marketing studies, acute increases in blood pressure requiring immediate treatment have been reported. All patients with a history of hypertension should have their blood pressure checked before starting treatment. Blood pressure should be checked periodically after starting treatment and after increasing the dose. Caution should be exercised when treating patients in whom increased blood pressure may affect underlying medical conditions, such as patients with cardiac dysfunction.
5. Heart rate
Venlafaxine may cause an increase in heart rate, especially at high doses. Caution should be exercised when treating patients in whom an increase in heart rate may affect underlying medical conditions.
6. Heart disease and risk of arrhythmia
Venlafaxine has not been studied in patients who have recently had a myocardial infarction or other heart disease. Therefore, it should be used with caution in such patients. In post-marketing data, fatal cardiac arrhythmias have been reported with the use of venlafaxine, especially in overdose. Before prescribing venlafaxine to patients at high risk of serious cardiac arrhythmias, the benefits and risks of this therapy should be considered.
7. Cramps
Seizures may occur during venlafaxine therapy. Like all antidepressants, venlafaxine should be used with caution in patients who regularly experience seizures. Such patients should be closely monitored during therapy. Treatment should be discontinued in any patient who experiences seizures.
8. Hyponatremia
Hyponatremia and/or syndrome of insufficient antidiuretic hormone secretion (SIADH) may occur during venlafaxine therapy, especially in patients with dehydration or decreased blood volume. Elderly patients, patients taking diuretics, and patients with reduced blood volume are at greater risk with therapy.
9 Abnormal bleeding
Medicines that interfere with the absorption of serotonin may cause decreased platelet function. The risk of bleeding from the skin and mucous membranes, including gastrointestinal bleeding, may increase while taking venlafaxine. Like other serotonin reuptake inhibitors, venlafaxine should be used with caution in the treatment of patients predisposed to bleeding, including patients on platelet inhibitors and anticoagulants.
10.Serum cholesterol
In a placebo-controlled clinical trial, there was a significant increase in serum cholesterol levels in 5.3% of patients treated with venlafaxine compared with 0% of patients treated with placebo for at least 3 months. During long-term therapy with venlafaxine, serum cholesterol levels should be measured regularly.
11. Simultaneous use with drugs for weight loss
The effectiveness and safety of treatment with venlafaxine in combination with weight loss drugs, including phentermine, have not been established. Concomitant use of venlafaxine and weight loss medications is not recommended. Venlafaxine is not indicated for the treatment of excess weight, either alone or in combination with other drugs.
12.Manic syndrome/hypomania
Manic syndrome/hypomania may occur in a small number of patients with mental disorders during treatment with antidepressants, including venlafaxine. As with other antidepressants, venlafaxine should be used with caution in patients with a history of bipolar disorder or a family history of bipolar disorder.
13.Aggression
When taking antidepressants, including venlafaxine, a small number of patients may experience aggression. It can be observed at the beginning of therapy, when changing the dosage of the drug and stopping treatment. Like other antidepressants, venlafaxine should be used with caution in patients who have had episodes of aggression.
14. Termination of treatment
Withdrawal syndromes after discontinuation of treatment are common, especially when therapy is abruptly stopped. In clinical trials, adverse events occurred at discontinuation of treatment (dose taper or thereafter) in approximately 35% of patients receiving venlafaxine and 17% of patients receiving placebo. The risk of withdrawal symptoms may depend on several factors, including duration of therapy, dosage, and rate of dosage reduction. Dizziness, sensory disturbances (including paresthesia), sleep disturbances (including insomnia and intense dreams), agitation or anxiety, nausea and/or vomiting, tremors and headaches are the most common side effects. Typically, all symptoms were mild to moderately severe, but in some patients they could be severe. They usually occur within the first few days after stopping treatment, but very rarely such symptoms have been reported in patients who accidentally missed one dose of the drug. Typically, these symptoms are self-limiting and resolve within 2 weeks, although in some people they may last longer (2-3 months or more). Therefore, we recommend that venlafaxine therapy be discontinued gradually over several weeks or months, depending on the patient's needs.
15. Akathisia/psychomotor agitation
The use of venlafaxine has been associated with the development of akathisia, which causes patients to experience unpleasant feelings of restlessness or anxiety, as well as a need to move regularly with an inability to sit or stand still. Most often, this occurs during the first few weeks of treatment. In patients who develop these symptoms, increasing the dosage may have harmful effects.
16. Dry mouth
Dry mouth was noted in 10% of patients taking venlafaxine. This may increase the risk of tooth decay. Patients should be reminded of the importance of oral hygiene.
Impact on the ability to drive vehicles and operate machinery
Although venlafaxine has not been shown to affect psychomotor function, thinking, or decision-making in healthy volunteers, any psychotropic drug may affect decision-making or psychomotor function. Therefore, patients should be warned not to drive a car or operate dangerous machinery.
Velafax, 37.5 mg, tablets, 28 pcs.
Depression increases the risk of suicidal thoughts and suicide attempts. This risk persists until stable remission occurs. Since improvement may not occur for the first few weeks or more of treatment, patients should be under constant medical supervision throughout this period until sustained improvement occurs. The risk of suicide attempts is highest immediately after starting the drug, but also increases again in the early stages of recovery. Venlafaxine should not be used in the treatment of children and adolescents under 18 years of age. In patients with a history of suicidal behavior or a tendency to develop suicidal thoughts before treatment, as well as in young adult patients, the risk of suicidal thoughts or suicide attempts is highest. Placebo-controlled clinical trials of antidepressants in adult patients with mental disorders showed an increased likelihood of suicidal behavior (suicide attempt and suicidal ideation) in persons under the age of 25 years receiving antidepressants, incl. venlafaxine.
Patients and caregivers should be warned to monitor for suicidal ideation and to seek immediate medical attention if symptoms occur.
As with treatment with other antidepressants, abrupt cessation of venlafaxine therapy (especially after high doses of the drug) may cause withdrawal symptoms, and therefore it is recommended to gradually reduce its dose before discontinuing the drug. The risk of withdrawal symptoms depends on the dose size, duration of therapy, and the individual sensitivity of the patient. In patients with affective disorders, when treated with antidepressants (including venlafaxine), hypomanic or manic states may occur. Venlafaxine (like other antidepressants) should be prescribed with caution to patients with a history of mania (such patients require medical supervision).
Like other antidepressants, venlafaxine should be administered with caution to patients with a history of epileptic seizures. Treatment with venlafaxine should be interrupted if epileptic seizures occur. The drug should not be prescribed to patients with uncontrolled epilepsy, and patients with controlled epilepsy require careful monitoring.
The use of venlafaxine may be associated with the development of psychomotor restlessness, which clinically resembles akathisia and is characterized by a subjectively unpleasant and distressing restlessness with a need to move, often combined with an inability to sit or stand still. This condition is most often observed during the first few weeks of treatment. If such symptoms occur, increasing the dose may have an adverse effect and the advisability of continuing venlafaxine should be considered.
Patients should be warned to seek immediate medical attention if rash, hives, or other allergic reactions occur.
Some patients experienced a dose-dependent increase in blood pressure while taking venlafaxine; therefore, regular blood pressure monitoring is recommended, especially during the period of dose selection or increase.
During treatment with the drug, an increase in heart rate is possible, especially when taken in high doses. Caution should be exercised when using the drug in patients with a tendency to tachycardia.
Patients, especially the elderly, should be warned about the possibility of dizziness and impaired balance (orthostatic hypotension).
In patients taking venlafaxine, changes in ECG parameters (prolongation of the PR interval, expansion of the QRS complex, prolongation of the QT interval) were rarely observed.
Venlafaxine should be prescribed with caution to patients who have recently suffered a myocardial infarction and with unstable angina, since the safety of the drug in this category of patients has not been studied.
Like other serotonin reuptake inhibitors, venlafaxine may increase the risk of bleeding into the skin and mucous membranes. Caution is necessary when treating patients predisposed to such conditions.
While taking venlafaxine, especially in conditions of dehydration or decreased blood volume (including in elderly patients and patients taking diuretics), hyponatremia and/or syndrome of insufficient ADH secretion may occur.
Mydriasis may occur while taking the drug, and therefore it is recommended to monitor intraocular pressure in patients prone to increased pressure or with angle-closure glaucoma.
It is not recommended to combine venlafaxine with weight loss agents (including phentermine) due to the lack of data on effectiveness and safety.
Clinical studies conducted to date have not revealed tolerance or dependence to venlafaxine. Despite this, the physician should closely monitor patients for signs of drug abuse (as with other drugs that act on the central nervous system). Patients with a history of drug dependence require special monitoring.
When using venlafaxine for a long period of time, monitoring of serum cholesterol levels is required.
The drug should be prescribed with caution if liver or kidney function is impaired. Sometimes a dose reduction may be necessary.
While taking venlafaxine, special care should be taken when conducting electroconvulsive therapy, because There is no experience with the use of venlafaxine in these conditions.
During the treatment period, alcohol consumption is not recommended.
Influence on the ability to drive vehicles and operate machinery.
Venlafaxine has virtually no effect on psychomotor and cognitive functions. However, given the possibility of significant side effects from the central nervous system, during treatment with venlafaxine, care must be taken when driving vehicles and engaging in potentially hazardous activities that require increased concentration and speed of psychomotor reactions.
