Understanding Lithium: the forgotten drug
Lithium is a naturally occurring element, the third on the periodic table, making it the lightest solid material in the known universe. Though used as a treatment for gout, table salt, and even a soft drink, lithium has been best known since 1949 as the gold standard for the treatment of bipolar manic episodes. However, in the midst of emerging atypical antipsychotics and anticonvulsants, lithium is often overlooked as an outdated treatment for Bipolar Disorder. This misconception could not be farther from the truth; today we will look at the unique potential lithium has as a treatment for bipolar disorder and unipolar depression. When prescribed correctly and managed carefully, lithium works as well as and often better than newer forms of bipolar treatment. It offers a significant reduction in the risk of suicide and accidental injury for both bipolar disorder and unipolar depression compared to others; though it treats manic symptoms far more effectively than depressive symptoms. It also has been shown to greatly increase time to recurrence of manic episodes when compared to other forms of treatment; though when tapered off too quickly it can increase the rate of occurrence worse than a placebo. A careful prescriber must also be sure to monitor certain vital functions in a person taking lithium and not give lithium to a patient with poor kidney function, psoriasis, or cardiac problems like congestive heart failure or certain dysrhythmias.
Though this chemical has been discovered for hundreds of years, and used as a treatment for mania for more than 60 years, the way it works is still not well understood. Some theories postulate that lithium’s adjustment of the amount of glutamate, dopamine, and GABA available in the brain is to blame for its effects. One thing we know for sure however is that it is not metabolized like most drugs. Its final destination is the kidney where it is filtered out into the urine. Lithium has a rapid absorption, working quickly and not dependent on whether you have eaten recently (though nausea may occur if the drug is taken without food). Lithium’s half-life is about 24 hours in a person with a well-functioning kidney, longer with kidney failure. Sodium (the 4th chemical on the periodic table) will therefore also greatly impact how much lithium remains in the body due to the interactions it has with our kidney’s function. A person who has a lot of sodium in their diet will find that lithium is flushed out faster, and low sodium or dehydration may cause toxicity. Elderly patients are also at a higher risk of toxicity due to reduced filtration rates. Lithium’s serum levels are increased by thiazide diuretics, NSAIDs (not including aspirin), ACE inhibitors, ARBs, and some antibiotics; while it is decreased by potassium-sparing diuretics and theophylline. Patients, but especially prescribers should be aware of all of these interactions. Lithium has some very serious side effects that, if they appear suddenly or with great severity can indicate toxicity. Common acute side effects that typically fade with time include postural tremor, loose stools, cognitive impairment (such as apathy or changes in memory and concentration), or weight gain. When taken for longer periods of time lithium can also cause renal failure, goiters, thyroid suppression, and cardiac arrhythmias. With consistent blood work monitoring and ECG’s, these problems can be treated or avoided.
Lithium has been, and continues to be the strongest weapon in our arsenal for combating bipolar disorder. It will only harm us to forget this powerful and useful drug and allow it fade into obscurity. With care and attention, a savvy prescriber can safely wield this incredibly useful tool against the battle for mental health. Authored by Daniel Rynn PA student, Barry University and Edited and posted by Dr. Vangala