Venlafaxine (Page 8 of 12)

7.9 Monoamine Oxidase Inhibitors (MAOIs)

[See Dosage and Administration (2.6 and 2.7), Contraindications (4.1), and Warnings and Precautions (5.2)].

7.10 Serotonergic Drugs

[See Dosage and Administration (2.6 and 2.7), Contraindications (4.1), and Warnings and Precautions (5.2) ].

7.11 Drugs that Interfere with Hemostasis (e.g., NSAID’s, Aspirin, and Warfarin)

Serotonin release by platelets plays an important role in hemostasis. Epidemiological studies of the case-control and cohort design that have demonstrated an association between use of psychotropic drugs that interfere with serotonin reuptake and the occurrence of upper gastrointestinal bleeding. These studies have also shown that concurrent use of an NSAID or aspirin may potentiate this risk of bleeding. Altered anticoagulant effects, including increased bleeding, have been reported when SSRI’s and SNRI’s are coadministered with warfarin. Patients receiving warfarin therapy should be carefully monitored when venlafaxine extended-release tablets are initiated or discontinued [see Warnings and Precautions (5.13) ].

7.12 Electroconvulsive Therapy

There are no clinical data establishing the benefit of electroconvulsive therapy combined with venlafaxine extended-release tablets treatment.

7.13 Postmarketing Spontaneous Drug Interaction Reports

There have been reports of elevated clozapine levels that were temporally associated with adverse reactions, including seizures, following the addition of venlafaxine.

There have been reports of increases in prothrombin time, partial thromboplastin time, or INR when venlafaxine was given to patients receiving warfarin therapy.

7.14 Drug-Laboratory Test Interactions

False-positive urine immunoassay screening tests for phencyclidine (PCP) and amphetamine have been reported in patients taking venlafaxine. This is due to lack of specificity of the screening tests. False positive test results may be expected for several days following discontinuation of venlafaxine therapy. Confirmatory tests, such as gas chromatography/mass spectrometry, will distinguish venlafaxine from PCP and amphetamine.

8 USE IN SPECIFIC POPULATIONS

8.1 Pregnancy

Teratogenic Effects

Pregnancy Category C

Venlafaxine did not cause malformations in offspring of rats or rabbits given doses up to 2.5 times (rat) or 4 times (rabbit) the maximum recommended human daily dose on a mg/m2 basis.

However, in rats, there was a decrease in pup weight, an increase in stillborn pups, and an increase in pup deaths during the first 5 days of lactation, when dosing began during pregnancy and continued until weaning. The cause of these deaths is not known. These effects occurred at 2.5 times (mg/m2) the maximum human daily dose. The no effect dose for rat pup mortality was 0.25 times the human dose on a mg/m2 basis. There are no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.

Non-Teratogenic Effects

Neonates exposed to venlafaxine hydrochloride extended-release capsules, other SNRIs (Serotonin and Norepinephrine Reuptake Inhibitors), or SSRIs (Selective Serotonin Reuptake Inhibitors), late in the third trimester have developed complications requiring prolonged hospitalization, respiratory support, and tube feeding. Such complications can arise immediately upon delivery. Reported clinical findings have included respiratory distress, cyanosis, apnea, seizures, temperature instability, feeding difficulty, vomiting, hypoglycemia, hypotonia, hypertonia, hyperreflexia, tremor, jitteriness, irritability, and constant crying. These features are consistent with either a direct toxic effect of SSRIs and SNRIs or, possibly, a drug discontinuation syndrome. It should be noted that, in some cases, the clinical picture is consistent with serotonin syndrome [see Warnings and Precautions (5.2) ]. When treating a pregnant woman with venlafaxine extended-release tablets during the third trimester, the physician should carefully consider the potential risks and benefits of treatment [see Dosage and Administration (2) ].

8.2 Labor and Delivery

The effect of venlafaxine on labor and delivery in humans is unknown.

8.3 Nursing Mothers

Venlafaxine and ODV have been reported to be excreted in human milk. Because of the potential for serious adverse reactions in nursing infants from venlafaxine extended-release tablets, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.

8.4 Pediatric Use

Safety and effectiveness in the pediatric population have not been established [see BOXED WARNING and Warnings and Precautions (5.1) ]. Two placebo-controlled trials in 766 pediatric patients with MDD and two placebo-controlled trials in another disorder in 793 pediatric patients have been conducted with venlafaxine hydrochloride extended-release capsules, and the data were not sufficient to support a claim for use in pediatric patients.

Anyone considering the use of venlafaxine extended-release tablets in a child or adolescent must balance the potential risks with the clinical need.

Although no studies have been designed to primarily assess impact of venlafaxine hydrochloride extended-release capsules on the growth, development, and maturation of children and adolescents, the studies that have been done suggest that venlafaxine extended-release tablets may adversely affect weight and height [see Warnings and Precautions (5.7, 5.8, and 5.9)]. Should the decision be made to treat a pediatric patient with venlafaxine extended-release tablets, regular monitoring of weight and height is recommended during treatment, particularly if it is to be continued long term. The safety of venlafaxine extended-release tablets treatment for pediatric patients has not been systematically assessed for chronic treatment longer than six months in duration.

In the studies conducted in pediatric patients (ages 6 to 17), the occurrence of blood pressure and cholesterol increases considered to be clinically relevant in pediatric patients was similar to that observed in adult patients. Consequently, the precautions for adults apply to pediatric patients [see Warnings and Precautions (5.3 and 5.14)].

8.5 Geriatric Use

Approximately 4% (14/357) and 2% (6/277) of patients treated with venlafaxine hydrochloride extended-release capsules in placebo-controlled premarketing major depressive disorder and Social Anxiety Disorder trials, respectively, were 65 years of age or over. Of 2,897 patients treated with venlafaxine hydrochloride immediate-release tablets in premarketing phase major depressive disorder studies, 12% (357) were 65 years of age or over. No overall differences in effectiveness or safety were observed between geriatric patients and younger patients, and other reported clinical experience generally has not identified differences in response between the elderly and younger patients. However, greater sensitivity of some older individuals cannot be ruled out. SSRIs and SNRIs, including venlafaxine hydrochloride extended-release capsules have been associated with cases of clinically significant hyponatremia in elderly patients, who may be at greater risk for this adverse reaction [see Warnings and Precautions (5.11) ].

The pharmacokinetics of venlafaxine and ODV are not substantially altered in the elderly [see Clinical Pharmacology (12.3) ]. No dose adjustment is recommended for the elderly on the basis of age alone, although other clinical circumstances, some of which may be more common in the elderly, such as renal or hepatic impairment, may warrant a dose reduction [see Dosage and Administration (2.3) ].

8.6 Patients with Hepatic Impairment

In patients with cirrhosis of the liver, the clearances of venlafaxine and its active metabolite (ODV) were decreased, thus prolonging the elimination half-lives of these substances. A large degree of intersubject variability was noted [see Clinical Pharmacology (12.3) ]. A lower dose and individualization of dosing may be necessary [see Dosage and Administration (2.3) ]. Venlafaxine extended-release tablets, like all drugs effective in the treatment of major depressive disorder, should be used with caution in such patients.

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