Lithium may cause fetal harm when administered to a pregnant woman. There have been reports of lithium having adverse effects on nidations in rats, embryo viability in mice, and metabolism in-vitro of rat testis and human spermatozoa have been attributed to lithium, as have teratogenicity in submammalian species and cleft palates in mice. Studies in rats, rabbits and monkeys have shown no evidence of lithium-induced teratology. Data from lithium birth registries suggest an increase in cardiac and other anomalies, especially Ebstein's anomaly. If the patient becomes pregnant while taking lithium, she should be apprised of the potential risk to the fetus. If possible, lithium should be withdrawn for at least the first trimester unless it is determined that this would seriously endanger the mother.
Chronic lithium therapy may be associated with diminution of renal concentrating ability, occasionally presenting as nephrogenic diabetes insipidus, with polyuria and polydipsia. Such patients should be carefully managed to avoid dehydration with resulting lithium retention and toxicity. This condition is usually reversible when lithium is discontinued.
Morphologic changes with glomerular and interstitial fibrosis and nephron-atrophy have been reported in patients on chronic lithium therapy. Morphologic changes have also been seen in bipolar patients never exposed to lithium. The relationship between renal functional and morphologic changes and their association with lithium therapy has not been established. To date, lithium in therapeutic doses has not been reported to cause end-stage renal disease.
When kidney function is assessed, for baseline data prior to starting lithium therapy or thereafter, routine urinalysis and other tests may be used to evaluate tubular function (e.g., urine specific gravity or osmolality following a period of water deprivation, or 24-hour urine volume) and glomerular function (e.g., serum creatinine or creatinine clearance). During lithium therapy, progressive or sudden changes in renal function, even within the normal range, indicate the need for reevaluation of treatment.
Lithium toxicity is closely related to serum lithium levels, and can occur at doses close to therapeutic levels (see DOSAGE ANDADMINISTRATION).