Is there long term affects of phentermine?

Answer 1

The Food and Drug Administration(FDA) that phentermine should be used short-term (usually interpreted as 'up to 12 weeks'), while following nonpharmacological approaches to weight loss such as healthy dieting and exercise.

Like all amphetamine-class drugs, phentermine has an addiction potential. Normal doses soon lose their effect, and increased doses become necessary in order to maintain the anorectic effects. Since it also raises blood pressure, that should be taken into account. Withdrawal symptoms occur after long dosage periods.