To the Editor.—
Drs. Solomon and Vickers (231:280, 1975) do not appear to appreciate that geriatric doses of psychoactive medication are lower than doses for younger people. Acceptable therapeutic lithium ion levels for people more than 50-60 years of age is 0.2 to 0.9 mEq/liter. For older people, 300-mg tablets of lithium carbonate often have to be broken in half; 150 mg three times daily is a frequent geriatric dosage. Sometimes even less is appropriate. For this reason, tablet form is better than capsule form of lithium carbonate.