Medications

More severe reactions, which occur at higher blood levels, include:

• Vomiting
• Convulsions
• Uncontrolled jerky movements in arms and legs
• Stupor
• Coma

Very high blood levels of lithium can be fatal.

If overdose occurs, drugs should be stopped immediately and one or more of the following steps taken, depending on the severity:

• Patients are given fluids and drugs to increase excretion of lithium salts.
• Gastric lavage, a procedure that rinses the stomach, may be used to treat very recent overdoses.
• Hemodialysis, a procedure that filters lithium out of the blood, may also be performed in severe cases.

Long-Term Side Effects. Even for patients who do not experience a severe response, long-term use of lithium is not without problems. In one study, 16% of patients gained weight. Weight gain is one of the main reasons why some patients want to stop taking the drug. Other side effects include:

• An unpleasant taste in the mouth
• Hair loss
• Skin eruptions that can resemble acne and make psoriasis worse
• Low thyroid function
• An increased risk for diabetes
• A blunted sexual drive
• Dulled emotions and lack of mental clarity
• Memory loss
• Lack of motor coordination
• Reduced sensitivity to light.

In some cases, light sensitivity may slightly affect a person's ability to recognize colors. More seriously, it can cause problems with night driving. This effect occurs regardless of how long a person has been on the drug. Experts recommend that patients wear sunglasses outside and avoid extensive exposure to bright light.

Drug Interactions. Because lithium is eliminated from the body by the kidneys, any drugs or dietary factors that slow the kidneys' actions may increase lithium blood levels and should be used with great caution. Such drugs include:

• Nonsteroidal anti-inflammatory drugs (NSAIDs)
• Thiazide diuretics
• ACE inhibitors

There have been reports of interactions between lithium and certain drugs commonly used in combination, including:

• Antipsychotics
• Anticonvulsants
• Calcium-channel blockers

The risks associated with these drug interactions are very low, but caution is needed.