14 Lithium

Lithium
Lithium Carbonate, known informally as "Lithium," is the oldest mood stabilizer currently prescribed. In many ways it is also the best and most effective mood stabilizer available. The American Psychiatric Association recommends lithium as first line therapy for bipolar disorders. Numerous clinical trials have proven its efficacy for treating mood disorders. Although lithium is often used during manic episodes, it is also proven to help patients during depressive episodes.
Lithium is usually prescribed in conjunction with other medications, because its effects are not instant or quick, but rather take some time to build up. Several days or even weeks may need to pass before lithium's full therapeutic effects are apparent. Due to this lag time, other drugs are frequently administered to handle the acute phases of bipolar disorder mood episodes. Lithium's most common use with regard to treating bipolar disorders is as a prophylactic (preventative) agent. Numerous clinical trials show that lithium is effective in stopping the onset of mood swing episodes, and reduces the frequency of relapses.
Although lithium is highly effective at reducing the frequency and intensity of mood swings, it is also a very difficult and potentially dangerous drug to offer patients. Lithium's therapeutic dose is uncomfortably close to its toxic dose, meaning it is rather easy to take too much lithium by mistake and become poisoned. Toxically high blood lithium levels can cause respiratory depression, seizures, coma and even death. A battery of laboratory tests including a complete blood count, tests for serum (blood) creatinine and electrolytes, hormones, and urinalysis must therefore be conducted before prescribing this medication, and thereafter repeated on a regular basis so as to provide adequate monitoring of lithium blood levels. A complete blood count measures the components of blood such as red and white blood cells and platelets which help blood to clot. This test makes sure that all these cells exist at normal levels, there is no unknown infection, and that the body can function normally in case of an injury. Measuring creatinine in blood serum is a test for kidney function. If creatinine levels are high it may mean that the kidneys are not fully functional. Since kidney function is essential to clearing lithium from the system (so as to avoid lithium toxicity) this test is particularly important before prescribing lithium to a patient. Tests for electrolytes, hormones, (thyroid, in particular) and urine components indicate the basic health of an individual and levels of hormones and other biochemicals that must be noted before treatment and be monitored throughout therapy. To avoid lithium toxicity, the patient must undergo regular blood monitoring to measure levels of lithium and make sure that they remain within an acceptable dose range. Blood lithium levels need to be monitored closely and most frequently during the early stages of treatment. However, as treatment stabilizes, blood monitoring can occur as little as every three to six months.
Normal side effects of lithium include tremors, weight gain, heavy urination, excessive thirst, decreased coordination, reduced memory and concentration, changes in hair quality and quantity, nausea or diarrhea, decreases in sexual desire and function, and an increase in white blood cell count. Lithium treatment also reduces thyroid function. It prevents the release of thyroid hormones leading to hypothyroidism. Regular monitoring of thyroid hormones is thus essential when taking lithium (in addition to regular monitoring of lithium blood toxicity levels). If a patient responds well to lithium treatment, then lithium is typically continued and depleted thyroid hormones are replaced or supplemented pharmaceutically. If a patient does not tolerate lithium very well, then alternative mood stabilizing medications may be tried.
As is the case with most medications, care needs to be taken to avoid drug interactions when taking lithium or unanticipated and potentially negative side effects may occur. Patients starting lithium maintenance therapy should make their prescribing psychiatrist aware of any additional medications that they may be taking. Even taking a simple Ibuprofen (e.g., Advil®) can potentially lead to problems. Classes of medications that may interact with lithium include nonsteroidal anti-inflammatory drugs (NSAIDS, including Ibuprofen), anti-hypertension drugs, and antibiotics.