Pharmacy Author: Omudhome Ogbru, PharmD
Medical and Pharmacy Editor: Jay W. Marks, MD

GENERIC NAME: lithium

BRAND NAME: Lithobid

DRUG CLASS AND MECHANISM: Lithium is used for the treatment of manic/depressive (bipolar) and depressive disorders. Lithium is a positively charged element or particle that is similar to sodium and potassium. It interferes at several places inside cells and on the cell surface with other positively charged atoms such as sodium, potassium, calcium, and magnesium which are important in many cellular functions.

Lithium interferes with the production and uptake of chemical messengers by which nerves communicate with each other (neurotransmitters). Lithium also affects the concentrations of tryptophan and serotonin in the brain. In addition, lithium increases the production of white blood cells in the bone marrow. Lithium's effects usually begin within 1 week of starting treatment, and the full effect is seen by 2 to 3 weeks.

Lithium has been used since the 1950's. The FDA approved lithium carbonate, the most common preparation, in 1970.

PRESCRIPTION: Yes

GENERIC AVAILABLE: Yes

PREPARATIONS: Tablets: 300, and 450mg. Capsules: 150, 300, and 600 mg. Syrup: 300 mg/5 ml

STORAGE: Tablets and capsules should be kept at room temperature, 15-30°C (59-86°F).

PRESCRIBED FOR: Lithium is used for treating manic episodes due to bipolar disorder (manic-depressive illness). It is also combined with antidepressants to treat depression.

DOSING: Doses vary widely and are adjusted based on measurements of the levels of lithium in the blood. Recommended blood levels are 06-1.2 mEq/L. Early in therapy, dose adjustments are made as often as every 5 to 7 days to establish the correct dose. Most patients require 900-1200 mg daily in 2-3 divided doses. Patients with kidney diseases excrete less lithium from the body and, therefore, require lower doses.

DRUG INTERACTIONS: Non-steroidal anti-inflammatory drugs (NSAIDs), [for example, ibuprofen (Motrin, Advil), naproxen Naprosyn, Aleve), indomethacin (Indocin), nabumetone (Relafen), diclofenac (Voltaren, Cataflam, Arthrotec), ketorolac (Toradol)], reduce the kidney's ability to eliminate lithium and lead to elevated levels of lithium in the blood and lithium side effects. Blood concentrations of lithium may need to be measured for 4 to 7 days after an NSAID is either added or stopped during lithium therapy. Aspirin and sulindac (Clinoril) do not appear to affect lithium concentrations in the blood.

Diuretics (water pills) should be used cautiously in patients receiving lithium. Diuretics that act at the distal renal tubule, [for example, hydrochlorothiazide (Hydrodiuril), spironolactone (Aldactone), triamterene (Dyrenium; Dyazide, Maxzide)], can increase blood concentrations of lithium. Diuretics that act at the proximal tubule, [for example, acetazolamide (Diamox)], are more likely to reduce blood concentrations of lithium. Diuretics such as furosemide (Lasix) and bumetanide (Bumex) may have no affect on lithium concentrations in blood.

ACE inhibitors, [for example, enalapril (Vasotec), lisinopril (Zestril, Prinivil), benazepril (Lotensin), quinapril (Accupril), moexipril (Univasc), captopril (Capoten), ramipril (Altace)], may increase the risk of developing lithium toxicity, by increasing the amount of lithium that is reabsorbed in the tubules of the kidney and thereby reducing the excretion of lithium.

When carbamazepine (Tegretol) and lithium are used together, some patients may experience side effects, including dizziness, lethargy, and tremor. Central nervous system side effects also may occur when lithium is used with antidepressants, [for example, fluoxetine (Prozac) sertraline (Zoloft), and paroxetine (Paxil), fluvoxamine (Luvox), amitriptyline (Elavil), imipramine (Tofranil), desipramine (Norpramin)].

Medications which cause the urine to become alkaline (the opposite of acidic) can increase the amount of lithium that is lost into the urine. This results in lower blood concentrations of lithium and reduces the effects of lithium. Such drugs include potassium acetate, potassium citrate (Urocit-K), sodium bicarbonate, and sodium citrate (Bicitra, Cytra-2, Liqui-Citra, Oracit, Shohl's).