DURACLON nonclinical toxicology

# Nonclinical Toxicology

## Carcinogenesis, Mutagenesis, Impairment of Fertility
In a 132-week study in rats, clonidine hydrochloride administered as a dietary admixture at 5-8 times (based on body surface area) the 50 mcg/kg maximum recommended daily human dose (MRDHD) for hypertension did not show any carcinogenic potential. Clonidine was inactive in the Ames test of mutagenicity. Fertility of male or female rats was unaffected by oral clonidine hydrochloride doses as high as 150 mcg/kg, or about 0.5 times the MRDHD. Fertility of female rats did, however, appear to be affected in another experiment at oral dose levels of 500-2000 mcg/kg, or 2-7 times the MRDHD.

## Usage in Pregnancy/Teratogenic Effects
PREGNANCY CATEGORY C
Reproduction studies in rabbits at clonidine hydrochloride doses up to approximately the MRDHD revealed no evidence of teratogenic or embryotoxic potential. In rats, however, doses as low as one-third the MRDHD were associated with increased resorptions in a study in which dams were treated continuously from 2 months prior to mating. Increased resorptions were not associated with treatment with the same or higher doses up to 0.5 times the MRDHD when dams were treated on days 6-15 of gestation. Increased resorptions were observed at higher levels (7-times the MRDHD) in rats and mice treated on days 1-14 of gestation.
Clonidine readily crosses the placenta and its concentrations are equal in maternal and umbilical cord plasma; amniotic fluid concentrations can be 4-times those found in serum. There are no adequate and well-controlled studies in pregnant women during early gestation when organ formation takes place. Studies using epidural clonidine during labor have demonstrated no apparent adverse effects on the infant at the time of delivery. However, these studies did not monitor the infants for hemodynamic effects in the days following delivery. Clonidine hydrochloride injection should be used during pregnancy only if the potential benefits justify the potential risk to the fetus.

## Labor and Delivery
There are no adequate controlled clinical trials evaluating the safety, efficacy, and dosing of Duraclon in obstetrical settings. Because maternal perfusion of the placenta is critically dependent on blood pressure, use of Duraclon as an analgesic during labor and delivery is not indicated (see WARNINGS).

## Nursing Mothers
Concentrations of clonidine in human breast milk are approximately twice those found in maternal plasma. Caution should be exercised when clonidine is administered to a nursing woman. Because of the potential for severe adverse reactions in nursing infants, a decision should be made to either discontinue nursing or to discontinue clonidine.

## Pediatric Use
The safety and effectiveness of Duraclon in this limited indication and clinical population have been established in patients old enough to tolerate placement and management of an epidural catheter, based on evidence from adequate and well controlled studies in adults and experience with the use of clonidine in the pediatric age group for other indications. The use of Duraclon should be restricted to pediatric patients with severe intractable pain from malignancy that is unresponsive to epidural or spinal opiates or other more conventional analgesic techniques. The starting dose of Duraclon should be selected on per kilogram basis (0.5 mcg per kg per hour) and cautiously adjusted based on the clinical response.