Although SSRI may lead to neurotoxicity at normal lithium levels, generally SSRI or atypical antidepressants do not impact lithium level. Yes, but the lithium level should be checked in 4-5 days to verify that the dose is correct. This equation should not be used for people with renal or cardiovascular disease, people beyond the age and weight limits, pregnant women, people taking diuretics or on salt restricted diets or people taking medications known to have significant impact on lithium levels. Age, weight, sex, inpatient versus outpatient and concurrent TCA administration were found to have the most impact on lithium dosage estimation. Lithium dose requirement increases with weight and decreases with age.
Males require more than females.
Inpatients require a slightly higher dose. Since lithium has a half-life of about 24 hours, dosing may be from once to twice daily. The estimating equation should be used with patients between the ages of 12 and 71 years who weigh between 84 and 266 pounds. The equation requires that the target blood level be entered. The reader is referred to standard textbooks on psychiatry for discussions of optimal lithium blood levels.