Phentermine 101: What You Need to Know Before Starting

Written by Olivera Weight Loss, Medically Reviewed by Jessica Ringwood, NP.

Woman doing an outdoor lunge stretch as part of an active weight loss routine.

Before starting phentermine, it’s important to understand the basics. Learning about this weight loss medication may help patients reach their weight loss goals as smoothly as possible. When used by adults who qualify under certain medical guidelines, phentermine can support weight loss by curbing hunger, as a personalized plan changes eating and activity patterns.

What Is Phentermine?

Phentermine is a prescription appetite suppressant approved by the FDA for short-term weight loss. It acts on the central nervous system to reduce hunger and can also help some patients feel more satisfied with smaller portions. According to its FDA labeling, phentermine is an adjunct to diet, exercise and behavior changes. Olivera often prescribes phentermine as one component of medically supervised weight loss rather than as the entire regimen.

Who It’s For—and Who It’s Not

Phentermine may be an option for adults with a BMI (body mass index) in the overweight or obese range. However, phentermine is not recommended for all patients due to contraindications. For example, if you’ve had heart problems, uncontrolled high blood pressure, an overactive thyroid, glaucoma or certain other conditions, another weight loss method might be a better option. Special considerations also apply to pregnant people and those taking certain medications. Here at Olivera, we review your medical history, current medications and goals during your consultation before prescribing phentermine.

What to Expect with Phentermine

Patients typically experience a reduced appetite and fewer cravings. This can help with portion control and make it easier to develop healthier eating habits. Many people feel more energetic or can focus better while taking phentermine. However, experiences vary from person to person. Report all changes to your provider at Olivera.

Common Side Effects and How They’re Managed

Phentermine has common side effects, including dry mouth, insomnia, nervousness, palpitations, increased heart rate and elevated blood pressure. Some side effects may be dose-related, which is why Olivera initiates treatment at the lowest possible dose. Patients are carefully monitored for any issues.

Report troublesome, severe or unusual problems to your Olivera provider right away; do not wait until your next visit. Patients should not change the dose on their own. The FDA also advises patients not to increase their dose on their own if they develop a tolerance.

Why Supervision Matters

Phentermine is a controlled substance, so medical monitoring is recommended to ensure safety. Scheduled check-ins with your provider at Olivera help ensure the medication is effective, discuss any side effects and make any necessary changes. Medical supervision also helps your provider identify interactions or health changes that may affect your treatment. We provide ongoing care, regularly check in on patients and adjust treatment based on your body’s response to the medication.

How It Fits Into a Bigger Picture

Phentermine is most effective as part of your overall weight loss program. Improving your diet, getting healthful exercise, and making long-term lifestyle changes remain essential. Your doctor wants you to understand that phentermine won’t automatically solve weight issues. With your appetite under control, it may make more sense to build realistic eating habits you can maintain after phentermine is no longer in your regimen. This transition should be taken seriously because choosing a weight loss medication is only one part of your weight loss journey. Olivera may prescribe boosters or supplements to support energy and metabolism if we feel they are necessary. Your plan will be tailored to you based on your medical history, your goals, and how you respond to medication.

What Makes Olivera’s Approach Different

Dr. Olivera has over 30 years of experience helping patients in the Chicago area achieve weight loss through medical care. Olivera offers no pressure and no gimmicks. Our medical care model focuses on medical attention and follow-up rather than writing a prescription with minimal follow-up. Patients can access in-person care, and we also offer telehealth follow-ups for eligible patients after two in-person visits. This allows easier monitoring at patients’ preferred location while maintaining follow-up treatment under clinical care.

Ready to Learn More?

While phentermine can help certain adults manage overweight and/or obesity, it’s not for everyone and is most effective as part of a comprehensive weight loss program. During your consultation, we can determine whether phentermine is right for your health history. Our team will discuss your options and walk you through what treatment may look like before writing your prescription. Ready to learn more? Book your consultation to see if phentermine fits your weight loss plan.