Pregnancy Category C
INTRON A has been shown to have abortifacient effects in Macaca mulatta (rhesus monkeys) at 15 and 30 million IU/kg (estimated human equivalent of 5 and 10 million IU/kg, based on body surface area adjustment for a 60-kg adult). There are no adequate and well-controlled studies in pregnant women. INTRON A therapy should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Pregnancy Category X applies to combination treatment with INTRON A and REBETOL (see CONTRAINDICATIONS). See REBETOL package insert for additional information. Significant teratogenic and/or embryocidal effects have been demonstrated in all animal species exposed to ribavirin. REBETOL therapy is contraindicated in women who are pregnant and in the male partners of women who are pregnant. See CONTRAINDICATIONS and the REBETOL package insert.

Ribavirin Pregnancy Registry: A Ribavirin Pregnancy Registry has been established to monitor maternal-fetal outcomes of pregnancies in female patients and female partners of male patients exposed to ribavirin during treatment and for 6 months following cessation of treatment. Physicians and patients are encouraged to report such cases by calling 1-800-593-2214.

Nursing Mothers
It is not known whether this drug is excreted in human milk. However, studies in mice have shown that mouse interferons are excreted into the milk. Because of the potential for serious adverse reactions from the drug in nursing infants, a decision should be made whether to discontinue nursing or to discontinue INTRON A therapy, taking into account the importance of the drug to the mother.

Pediatric Use

General
Safety and effectiveness in pediatric patients have not been established for indications other than chronic hepatitis B and chronic hepatitis C.

Chronic Hepatitis B
Safety and effectiveness in pediatric patients ranging in age from 1 to 17 years have been established based upon one controlled clinical trial (see CLINICAL PHARMACOLOGY, INDICATIONS AND USAGE, and DOSAGE AND ADMINISTRATION, Chronic Hepatitis B Pediatrics section).

Chronic Hepatitis C
Safety and effectiveness in pediatric patients ranging in age from 3 to 16 years have been established based upon clinical studies in 118 patients. See REBETOL package insert for additional information. Suicidal ideation or attempts occurred more frequently among pediatric patients compared to adult patients (2.4% vs 1%) during treatment and off-therapy follow-up (see WARNINGS, Neuropsychiatric Disorders section). During a 48-week course of therapy there was a decrease in the rate of linear growth (mean percentile assignment decrease of 7%) and a decrease in the rate of weight gain (mean percentile assignment decrease of 9%). A general reversal of these trends was noted during the 24-week post-treatment period.

Geriatric Use
In all clinical studies of INTRON A, including studies as monotherapy and in combination with REBETOL (ribavirin, USP) Capsules, only a small percentage of the subjects were aged 65 and over. These numbers were too few to determine if they respond differently from younger subjects except for the clinical trials of INTRON A in combination with REBETOL, where elderly subjects had a higher frequency of anemia (67%) than did younger patients (28%).

In a database consisting of clinical study and postm