Can phentermine (phentermine hydrochloride) be prescribed via a telehealth visit for a patient with a body mass index (BMI) of 30 or higher, or a BMI of 27 or higher with weight-related conditions such as hypertension, type 2 diabetes mellitus, or hypercholesterolemia?

Telehealth Prescribing of Phentermine

Yes, phentermine can be prescribed via telehealth visits for weight management in patients meeting BMI criteria (≥30 kg/m² or ≥27 kg/m² with comorbidities), as demonstrated by high-quality evidence showing non-inferiority of virtual visits compared to in-person encounters. 1

Evidence Supporting Telehealth Prescribing

A prospective randomized controlled trial directly compared virtual visits versus in-person visits for phentermine prescribing over 12 weeks and found that telehealth delivery was non-inferior at all time points 1:

• Virtual visit patients achieved mean weight loss of 6.5% compared to 7.7% in the in-person group 1
• 65% of virtual patients achieved ≥5% weight loss compared to 71% of in-person patients 1
• No differences were observed in medication tolerance, adherence, or compliance between groups 1

FDA-Approved Indications for Phentermine

Phentermine is FDA-approved as a short-term adjunct (a few weeks) for weight reduction in 2:

• Patients with BMI ≥30 kg/m² 2
• Patients with BMI ≥27 kg/m² in the presence of risk factors such as controlled hypertension, diabetes, or hyperlipidemia 2

Pre-Prescribing Requirements for Telehealth Visits

Before prescribing phentermine via telehealth, you must screen for absolute contraindications and obtain baseline measurements 3, 2:

Cardiovascular Assessment

• Measure baseline blood pressure and heart rate 3
• Screen for history of cardiovascular disease (coronary artery disease, stroke, arrhythmias, congestive heart failure, uncontrolled hypertension) - these are absolute contraindications 3, 2

Additional Contraindication Screening

• Assess pregnancy status in all females of reproductive potential - phentermine is contraindicated in pregnancy 3, 2
• Screen for hyperthyroidism 3, 2
• Screen for glaucoma 3, 2
• Assess for agitated states or anxiety disorders 3, 2
• Verify no current or recent (within 14 days) monoamine oxidase inhibitor use 3, 2
• Screen for history of drug abuse 2

Renal Function

• Limit dosage to 15 mg daily for patients with severe renal impairment (eGFR 15-29 mL/min/1.73 m²) 2

Dosing and Administration

• Start with the lowest effective dose (15 mg daily) and titrate as needed 4
• Maximum dose is 37.5 mg daily 2
• Administer in the morning to avoid insomnia 2
• Can be taken with or without food 3

Monitoring Requirements During Telehealth Follow-Up

• Monitor blood pressure and heart rate at every visit 3
• Assess weight loss at 12 weeks: discontinue if <5% weight loss achieved on maximum dose 3
• Consider discontinuation or dose escalation if <3% weight loss at 12 weeks on standard dose 3

Duration of Therapy

While FDA approval is for short-term use (12 weeks), many practitioners use phentermine longer in off-label fashion for chronic weight management 3:

• The decision to continue beyond 12 weeks should be based on efficacy (achieving ≥5% weight loss) and absence of cardiovascular contraindications 3
• If continued beyond 12 weeks, maintain periodic monitoring of blood pressure and heart rate at every visit 3

Common Pitfalls to Avoid

• Do not prescribe to patients with any history of cardiovascular disease, even if well-controlled 3, 2
• Do not confuse phentermine monotherapy with the discontinued "fen-phen" combination - the cardiac risks (valvular disease, pulmonary hypertension) were attributed to fenfluramine, not phentermine 3
• Do not combine with other weight loss medications without careful consideration of safety 2
• Do not exceed recommended doses in an attempt to overcome tolerance 3

Patient Counseling for Telehealth Visits

• Counsel that phentermine is FDA-approved for short-term use, though off-label longer duration is common in practice 3
• Discuss common side effects: dry mouth, difficulty sleeping, dizziness, irritability, constipation 3
• Advise against alcohol use during treatment 2
• Warn about potential impairment of ability to operate machinery or drive 2
• Emphasize that phentermine is a Schedule IV controlled substance with abuse potential 5