Pre‑Treatment Evaluation for Phentermine (Adipex) Therapy

Cardiovascular Assessment

• Obtain baseline blood pressure and heart rate at the initial visit because phentermine produces modest sympathetic‑mediated increases in both parameters. 2

• Perform a comprehensive renal function assessment (e.g., serum creatinine/eGFR) when considering phentermine, especially in patients with diabetes or when combination therapy is contemplated. 2

Eligibility Based on Body‑Mass Index

• Confirm that the patient’s BMI is ≥27 kg/m² with at least one weight‑related comorbidity or ≥30 kg/m² without comorbidities before initiating phentermine therapy. 4

Pregnancy and Reproductive‑Health Screening

• Verify that women of reproductive potential are not pregnant; phentermine is absolutely contraindicated during pregnancy. 1 (Praxis citation retained because no alternative source provided.)

Endocrine and Ophthalmologic Contraindications

• Exclude hyperthyroidism prior to prescribing phentermine because additive sympathomimetic effects may precipitate adverse events. 1

• Screen for a history of glaucoma (particularly angle‑closure type) as sympathomimetic agents can exacerbate intra‑ocular pressure. 1

Psychiatric and Medication Interaction Review

• Assess for active anxiety, agitation, substance‑use disorders, or recent monoamine‑oxidase‑inhibitor (MAOI) use (within 14 days) because these conditions increase the risk of hypertensive crisis or psychiatric adverse effects with phentermine. 1

Metabolic Laboratory Considerations for Combination Products

• If the phentermine‑topiramate combination is being considered, obtain a serum bicarbonate level to identify patients at risk for metabolic acidosis. 2

Common Adverse Effects and Patient Counseling

• Inform patients that typical side effects include dry mouth, insomnia, dizziness, irritability, modest rises in blood pressure, and increased heart rate. 4

• Emphasize that FDA approval is limited to short‑term use (approximately 3 months); continuation beyond this period should be based on clinical judgment and patient response. 1

Monitoring Plan and Discontinuation Criteria

• Re‑measure blood pressure and heart rate at every follow‑up visit. Discontinue phentermine if the patient fails to achieve at least 5 % weight loss after 12 weeks on the maximum recommended dose. 1

Alternative Pharmacologic Options for High‑Risk Patients

• Offer orlistat, a lipase inhibitor without sympathomimetic activity, for patients with cardiovascular contraindications. 2

• Consider GLP‑1 receptor agonists (e.g., semaglutide 2.4 mg or liraglutide 3.0 mg) which provide greater weight‑loss efficacy and have favorable cardiovascular safety profiles. 1

All facts are derived from cited peer‑reviewed sources; where multiple citations existed, non‑Praxis references were prioritized.