Side Effects of Lithium in Women with Bipolar Disorder

Each year more women than men are diagnosed with bipolar type II disorder. Though bipolar type I disorder occurs equally in men and women, a particularly severe form of bipolar I disorder known as "rapid-cycling" (4 or more manic episodes a year) is more common in women than in men. Thus the majority of patients on lithium, the gold standard treatment for bipolar disorder, are also women.

Lithium can, unfortunately, cause numerous side effects in patients with bipolar (also called manic depression). Lithium is said to have a low therapeutic index, meaning that the levels at which it is therapeutic are close to the levels at which lithium causes toxic effects. As a potentially lethal medication, lithium requires frequent blood tests and monitoring.

Some lithium side effects are concerning for both women and men, such as seizures, cardiac arrhythmias, weight gain, diabetes insipidus, hair loss, swelling, and coma.

Other adverse effects and contraindications of lithium are particularly important for women to be aware of. These include concerns regarding pregnancy, breast feeding, thyroid function and central nervous system side effects.

Thyroid effects:

Thyroid disease is much more common in females than in males. Lithium should be used with caution in women with thyroid disease. Adverse effects on the thyroid that have been seen in women include euthyroid goiter (thyroid swelling with normal thyroid hormone levels), hypothyroidism and hyperthyroidism.

Central nervous system effects:

Lithium can cause a particular side effect in the central nervous system known as pseudotumor cerebri. This condition is created by increased pressure around the brain, known as intracranial hypertension.

Pseudotumor cerebri is significantly more common in women, particularly obese women on oral contraceptives (birth control pills). Thus women who are also on lithium should be aware of the signs and symptoms of this medical condition.

Pregnancy:

Lithium is considered a schedule D drug for pregnant women because lithium can cause congenital malformations. During the first trimester of pregnancy, cardiac malformations, including Ebstein's anomaly, can occur in the infant. In addition, lithium can cause effects in the newborn infant immediately before and after birth when used near full term.

These negative effects include shallow breathing, muscular floppiness known as hypotonia, lethargy, cyanosis (blue extremities or around the mouth and chest), diabetes insipidus (deficiency or insensitivity to antidiuretic hormone), thyroid depression, and nontoxic goiter (thyroid enlargement).

All women who are not post-menopausal or known to be sterile for other reasons should have a negative beta-hCG pregnancy test before starting lithium therapy. An effort should be made to avoid lithium use during the first trimester if at all possible.

If pregnant women with bipolar disorder is not adequately treated on an alternative therapy and is a danger to her pregnancy, the lowest possible dose of lithium should be used throughout the pregnancy.

Ultrasound to screen for congenital anomalies and heart defects in the infant should be conducted between 16 and 20 weeks of gestation. Lithium levels should be monitored in the mother and may need to be adjusted following delivery of the infant.

Lactation:

Lithium is known to enter the breast milk. Given the adverse effects on the infant as stated above, a new mother who is medicated with lithium should not breast feed. Lithium is contraindicated in women who desire to breast feed their infant.

Many more women than men are being treated with lithium. Women should know that lithium can cause many side effects of great importance to the female sex. Individuals with questions or concerns regarding their medication should always contact their health care provider.

Source: LexiDrugs, LexiComp Online. 2010.