Hydrochlorothiazide had no adverse effects on the fertility of mice and rats of either sex in studies wherein these species were exposed, via their diet, to doses of up to 100 and 4 mg/kg/day, respectively, prior to mating and throughout gestation.

Lopressor HCT: No evidence of adverse effects on pregnancy or the fetus were observed in rats when dams were administered gavaged doses up to 200/50 mg/kg of Lopressor HCT (100/50 times the maximum recommended daily human dose) during the period of organogenesis. Increased postimplantation loss and decreased postnatal survival were observed with these doses when administered later in pregnancy (gestation days 15-21). In rabbits, increased fetal loss was observed with oral doses of 25/6.25 mg/kg of Lopressor HCT (12/6 times the maximum recommended daily human dose), but not with lower doses. There are no adequate and well-controlled studies of Lopressor HCT in pregnant women. Lopressor HCT should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Lopressor: Lopressor has been shown to increase postimplantation loss and decrease neonatal survival in rats at doses up to 55.5 times the maximum daily human dose of 450 mg. Distribution studies in mice confirm exposure of the fetus when Lopressor is administered to the pregnant animal. These studies have revealed no evidence of teratogenicity.

Hydrochlorothiazide: Studies in which hydrochlorothiazide was orally administered to pregnant mice and rats during their respective periods of major organogenesis at doses up to 3000 and 1000 mg/kg/day, respectively, provided no evidence of harm to the fetus.

Hydrochlorothiazide: Thiazides cross the placental barrier and appear in cord blood, and there is a risk of fetal or neonatal jaundice, thrombocytopenia, and possibly other adverse reactions that have occurred in adults.

Lopressor is excreted in breast milk in a very small quantity. An infant consuming 1 liter of breast milk daily would receive a dose of metoprolol of less than 1 mg. Thiazides are also excreted in breast milk. If the use of Lopressor HCT is deemed essential, the patient should stop nursing.

Safety and effectiveness in pediatric patients have not been established.

Clinical studies of Lopressor HCT did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. Hydrochlorothiazide is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function (see WARNINGS). In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and concomitant disease or other drug therapy.

The following adverse reactions were reported in controlled clinical studies of the combinati