Weight Loss Treatment with Topiramate

Introduction to Topiramate

• The maximum dose of topiramate for weight loss is 92 mg daily when used in the FDA-approved combination with phentermine (Qsymia), with the highest strength formulation containing 15 mg phentermine/92 mg topiramate extended-release 1, 2, 3

Dosing Protocol

• The recommended dosing protocol for phentermine/topiramate extended-release (Qsymia) is: starting dose of 3.75 mg phentermine/23 mg topiramate ER once daily for 14 days, maintenance dose of 7.5 mg phentermine/46 mg topiramate ER once daily, and if inadequate response, consider escalation to 11.25 mg phentermine/69 mg topiramate ER for 14 days, then increase to maximum dose of 15 mg phentermine/92 mg topiramate ER once daily 2, 3

Efficacy of Topiramate

• The efficacy of topiramate for weight loss is dose-dependent, with a 7.5 mg/46 mg dose resulting in 6.7 kg (7.8%) weight loss compared to 1.2% with placebo, and a 15 mg/92 mg dose resulting in 8.9 kg (9.8%) weight loss compared to 1.2% with placebo 1, 2
• Long-term data from the SEQUEL trial showed persistent weight loss at 108 weeks, with 9.3% weight loss with 7.5/46 mg dose and 10.5% weight loss with 15/92 mg dose 2

Monitoring and Discontinuation

• Assess efficacy and safety at least monthly for the first 3 months, then quarterly thereafter 4
• Early response (>5% weight loss after 3 months) predicts better long-term outcomes 4
• If less than 5% weight loss is achieved after 12 weeks on maximum dose (15/92 mg), discontinue treatment 2
• When discontinuing, taper by taking one capsule every other day for at least one week to minimize seizure risk 3

Safety and Contraindications

• Topiramate is teratogenic and associated with cleft lip/palate, and women of reproductive potential must use effective contraception 1, 2
• Common side effects include paresthesia, dizziness, dysgeusia, insomnia, constipation, and dry mouth 2
• Monitoring requirements include regular assessment of serum bicarbonate levels 5
• Contraindications include uncontrolled hypertension, history of glaucoma, and suicidality 5

Special Considerations

• Topiramate may be particularly beneficial for patients with comorbid migraine headaches, as it is FDA-approved for migraine prophylaxis 2, 6
• Discontinuation should be gradual to minimize risk of seizures 3