Antidepressants
Venlafaxine 25 mg
30Tablets
T33
362/2004
17/6/2004
Mechanism Of Action | The mechanism of the antidepressant action of venlafaxine in humans is believed to be associated with its potentiation of neurotransmitter activity in the CNS. Preclinical studies have shown that venlafaxine and its active metabolite, O-desmethylvenlafaxine (ODV), are potent inhibitors of neuronal serotonin and norepinephrine reuptake and weak inhibitors of dopamine reuptake. Venlafaxine and ODV have no significant affinity for muscarinic, cholinergic, H-histaminergic, or a-1 adrenergic receptors in vitro. Pharmacologic activity at these receptors is hypothesized to be associated with the various anticholinergic, sedative, and cardiovascular effects seen with other psychotropic drugs. Venlafaxine and ODV do not possess monoamine oxidase (MAO) inhibitory activity. |
INDICATIONS | tablets are used for the symptomatic relief of depressive illness |
CONTRAINDICATIONS | Venlafaxine hydrochloride is contraindicated in patients known to be hypersensitive to it. Concomitant use in patients taking monoamine oxidase inhibitors (MAOIs) is contraindicated. |
Side EFFECTS | Side effects that may go away during treatment, include drowsiness, dizziness, weakness, nausea, decreased appetite, dry mouth, constipation, change in sexual function, increased sweating, nervousness, or tremor. If they continue or are bothersome, consult your physician. CHECK WITH YOUR DOCTOR AS SOON AS POSSIBLE if you experience continuing headache, blurred vision, or continued weight loss. |
WARNINGS | Treatment with venlafaxine may associate with modest but sustained increases in blood pressure. For patients who experience a sustained increase in blood pressure during treatment with venlafaxine, either a dose reduction or discontinuation of venlafaxine should be considered. Close supervision of high-risk patients should accompany initial drug therapy, and consideration should be given to the need for hospitalization. Venlafaxine should be used cautiously in patients with a history of seizures, and should be promptly discontinued in any patient who develops seizures. As with all antidepressants, venlafaxine should be used cautiously in patients with a history of mania. Caution is advised in administering venlafaxine to patients with diseases or conditions that could affect hemodynamic responses or metabolism. Venlafaxine should be used with causion in patients with myocardial infarction or unstable heart disease as the mean heart rate may increase by about 4 beats per minute during treatment. In patients with hepatic or renal disease the pharmacokinetic disposition of both venlafaxine and ODV are significantly altered. Dosage adjustment is necessary in these patients. Any psychoactive drug may impair judgement, thinking or motor skills. Therefore, patients should be cautioned about operating hazardous machinery, including automobiles, until they are reasonably certain that the drug treatment does not affect them adversely. Venlafaxine should only be used during pregnancy if clearly needed. Because many drugs are excreted in human milk, lactating women should not nurse their infants while receiving venlafaxine. Asthenia, dizziness, headache, insomnia, nausea and nervousness may develop after discontinuation of Venlafaxine. Therefore, it is recommended that the dosage be tapered gradually and the patient monitored |
DRUG INTERACTIONS | Concomitant administration of cimetidine and venlafaxine may result in inhibition of first-pass metabolism of venlafaxine. Caution is advised if the concomitant administration of venlafaxine and such drugs is required. Caution is also advised if the concomitant administration of venlafaxine and CNS active drugs is required. Drug \ Clinical Laboratory Test Interactions: An increase in serum cholesterol has been reported in clinical trials. |
Pregnancy And lactations | Venlafaxine should only be used during pregnancy if clearly needed. Because many drugs are excreted in human milk, lactating women should not nurse their infants while receiving venlafaxine. Asthenia, dizziness, headache, insomnia, nausea and nervousness may develop after discontinuation of Venlafaxine. Therefore, it is recommended that the dosage be tapered gradually and the patient monitored. |
Dosage And Administration | The recommended treatment dose is 75 mg per day, administered in two or three divided doses (one tablet of VENEXOR-25 mg 3 times daily), taken with food. If the expected clinical improvement does not occur after a few weeks, a gradual dose increase to 150 mg/day may be considered. If needed, the dose may be further increased up to 225 mg/day. Increments of up to 75 mg/day should be made at intervals of no less than 4 days. The maximum dose recommended is 375 mg per day (in an inpatient setting). Patients With Hepatic and Renal Impairment: Given the decrease in clearance and increase in elimination half-life for both venlafaxine and ODV that is observed in patients with hepatic or renal impairment, it is recommended that the total daily dose be reduced by about 50% in such patients. Geriatrics: No dose adjustment is recommended for elderly patients on the basis of their age. As with any antidepressant, however, caution should be exercised in treating the elderly. Discontinuing Venlafaxine: When venlafaxine therapy that has been administered for more than 1 week is stopped, it is generally recommended that the dose be tapered gradually to minimize the risk of discontinuation symptoms. Patients who have received venlafaxine for 6 weeks or more should have their dose tapered gradually over a 2-week period. Maintenance/Extended Treatment: It is generally agreed, that pharmacological treatment for acute episodes of depression should continue for up to six months or longer. Switching Patients To Or From A Monoamine Oxidase Inhibitor: At least 14 days should elapse between discontinuation of an MAOI and initiation of therapy with venlafaxine HCl. In addition, at least 7 days should be allowed after stopping venlafaxine. |
OVERDOSE | The most common symptoms associated with Venlafaxine overdosage include somnolence, convulsions, a prolongation of QTc to 500 msec, compared with 405 msec at baseline, and a mild sinus tachycardia.Treatment should consist of those general measures employed in the management of overdosage with any antidepressant. Ensure an adequate airway, oxygenation, and ventilation. Monitoring of cardiac rhythm and vital signs is recommended. General supportive and symptomatic measures are also recommended. Use of activated charcoal, induction of emesis, or gastric lavage should be considered. No specific antidotes for venlafaxine HCl are known |
Storage Conditions | store below 30°C in a dry place keep out of reach of children . to be sold by prescription only . |