Dosage should be individualized to obtain an adequate response with the lowest effective dose.
The usual adult dose is one tablet three times a day ½ hour before meals. This tablet is scored to facilitate administering one half of the usual dosage for patients not requiring the full dose. Phentermine hydrochloride is not recommended for use in pediatric patients less than or equal to 16 years of age.

Late evening medication should be avoided because of the possibility of resulting insomnia.