8 USE IN SPECIFIC POPULATIONS
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. In reproductive developmental studies in rats and rabbits with O-desmethylvenlafaxine (ODV), the major human metabolite of venlafaxine, evidence of teratogenicity was not observed at exposure margins of 13 in rats and 0.3 in rabbits. There are no adequate and well-controlled studies in pregnant women. Effexor XR should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.
Neonates exposed to Effexor XR, other SNRIs, or SSRIs, 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) and Drug Interactions (7.3)]. When treating a pregnant woman with Effexor XR during the third trimester, the physician should carefully consider the potential risks and benefits of treatment.
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 Effexor XR, 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
Two placebo-controlled trials in 766 pediatric patients with MDD and two placebo-controlled trials in 793 pediatric patients with GAD have been conducted with Effexor XR, and the data were not sufficient to support a claim for use in pediatric patients.
Anyone considering the use of Effexor XR in a child or adolescent must balance the potential risks with the clinical need [see Boxed Warning, Warnings and Precautions (5.1, 5.10, 5.11) and Adverse Reactions (6.4)].
Although no studies have been designed to primarily assess Effexor XR's impact on the growth, development, and maturation of children and adolescents, the studies that have been done suggest that Effexor XR may adversely affect weight and height [see Warnings and Precautions (5.10)]. Should the decision be made to treat a pediatric patient with Effexor XR, regular monitoring of weight and height is recommended during treatment, particularly if treatment is to be continued long-term [see Warnings and Precautions (5.10, 5.11)]. The safety of Effexor XR 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 6–17), 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, 6.3)].
8.5 Geriatric Use
The percentage of patients in clinical studies for Effexor XR for MDD, GAD, SAD, and PD who were 65 years of age or older are shown in Table 15.
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 Effexor XR, have been associated with cases of clinically significant hyponatremia in elderly patients, who may be at greater risk for this adverse event [see Warnings and Precautions (5.9)].
The pharmacokinetics of venlafaxine and ODV are not substantially altered in the elderly [see Clinical Pharmacology (12.3)] (see Figure 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 (2.6)].
8.6 Age and Gender
A population pharmacokinetic analysis of 404 Effexor-treated patients from two studies involving both twice daily and three times daily regimens showed that dose-normalized trough plasma levels of either venlafaxine or ODV were unaltered by age or gender differences. Dosage adjustment based on the age or gender of a patient is generally not necessary [see Dosage and Administration (2.6)] (see Table 15).
8.7 Use in Patient Subgroups
|Figure 3: Pharmacokinetics of venlafaxine and its metabolite O-desmethylvenlafaxine (ODV) in special populations.|
Abbreviations: ODV, O-desmethylvenlafaxine; AUC, area under the curve; Cmax, peak plasma concentrations;
*Similar effect is expected with strong CYP2D6 inhibitors