The equivalent dose of Lexapro is approximately half of that of Celexa. This means the dosing range of Lexapro is 10-20 mg/day and the dosing range for Celexa is 20-40 mg/day. In elderly patients, the dosing range for Lexapro is reduced to 5-10 mg/day and for Celexa, 10-20 mg/da...