We cannot Prescribe Weight Loss Medications like Phentermine to People who are not Overweight Enough. Probably the most straightforward way to determine if you qualify for our medical weight loss program is to check your BMI or Body Mass Index using the little widget in the upper left of this section. The categories for BMI tell you if your level of body fat is within a healthy range. A BMI under 18.5 is considered underweight, 18.5 to 24.9 is considered normal, 25 to 29.9 is overweight and 30 and above is obese. I just started taking phentermine 2 weeks ago and have lost 8 pounds(132 right now) 5'2. My goal is to get back to 115-110 which is a healthy weight for my height. How to use Phentermine HCL. Take this medication by mouth as directed by your doctor, usually once a day, 1 hour before breakfast or 1 to 2 hours after breakfast. Concomitant use of alcohol with phentermine may result in an adverse drug reaction. potentially hazardous activities such as operating machinery or driving Body mass index (BMI) is a measure of body fat based on height and weight that applies to adult men and women. Enter your weight and height using standard or metric measures. Select Compute BMI and your BMI will appear below. AlaskaONE is the original internet based Alaska travel guide. AlaskaONE lists 100's of independent Alaska businesses of all sizes. AlaskaONE is your resource to learn about Alaska's diverse Parks & Places. The limited usefulness of agents of this class, including Phentermine, [see Clinical Pharmacology (12.1, 12.2)] should be measured against possible risk factors inherent in their use such as those described below. Phentermine is similar to an amphetamine. It stimulates the central nervous system (nerves and brain), which increases your heart rate and blood pressure and decreases your appetite. Phentermine 37.5 mg has a very simple and easy to remember dosing schedule. You must begin treatment with one capsule of Phentermine 37.5 mg (in the morning), at approximately a 24-hour interval.