Phentermine is available in the following doses: 15 mg, 30 mg and 37.5 mg.
People react differently to different doses of phentermine. Your doctor should prescribe the least amount needed to produce the desired effect of appetite suppression. Doctors normally start their patients either on phentermine 30 mg or phentermine 37.5 mg. Some doctors prefer to prescribe phentermine 15 mg initially and increase the dose if necessary, or some doctors may advise patients to split a 37.5 mg tablet, therefore representing a dosage of 18.75 mg. Over time your body may become used to the effects of phentermine and your doctor may decide to increase your dosage to prolong the suppression of hunger throughout the day. Your reaction should be monitored and changes in dosage made accordingly, but only following the recommendation of your doctor.
Phentermine is available in tablet or capsule form; the tablets can be spilt to halve the dosage but the capsules cannot be broken.