Qsymia Vs. Zepbound: Drug Comparison

Qsymia^® (phentermine and topiramate) is a prescription medication used for chronic weight management in adults with obesity or overweight with at least one weight-related condition, such as hypertension, type 2 diabetes, or high cholesterol. It combines two active ingredients: phentermine, an appetite suppressant, and topiramate, which induces a feeling of fullness and reduces appetite. Qsymia is intended to be used alongside a reduced-calorie diet and increased physical activity. Common side effects include dry mouth, constipation, and tingling sensations in the hands and feet. It should be used with caution due to potential risks such as mood changes, increased heart rate, and birth defects if taken during pregnancy.

Zepbound^® (tirzepatide) is an injectable medication approved by the FDA for chronic weight management in adults with obesity or overweight who have at least one weight-related condition. It works by activating both glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) hormone receptors, which help reduce appetite and food intake. It is taken once a week as an injection and is gradually increased over time to achieve effective weight loss results. Common side effects include nausea, diarrhea, constipation, and abdominal pain, with more serious risks like thyroid tumors and pancreatitis necessitating careful patient screening. This medication should be used alongside a reduced-calorie diet and increased physical activity for best results.

Phentermine: sympathomimetic amine anorectic

Topiramate: anticonvulsant

Glucose-dependent insulinotropic polypeptide (GIP) receptor and glucagon-like peptide-1 (GLP-1) receptor agonist

Qsymia (phentermine and topiramate) is indicated:

• As an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in:

  • Adults with an initial body mass index (BMI) of:

    • 30 kg/m² or greater (obese) or

    • 27 kg/m² or greater (overweight) in the presence of at least one weight-related comorbidity such as hypertension, type 2 diabetes mellitus, or dyslipidemia

  • Pediatric patients aged 12 years and older with BMI in the 95th percentile or greater standardized for age and sex

Zepbound (tirzepatide) is indicated:

• As an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of:

  • 30 kg/m² or greater (obesity) or

  • 27 kg/m² or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, dyslipidemia, type 2 diabetes mellitus, obstructive sleep apnea or cardiovascular disease)

• Typically taken orally once daily

• Comes in 3.75 mg/23 mg, 7.5 mg/46 mg, 11.25 mg/69 mg, and 15 mg/92 mg extended-release capsules

• Typically taken as an injection once weekly

• Comes in 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, and 15 mg per 0.5 mL single-dose pens or single-dose vials

Most common adverse reactions in adults (incidence ≥5% and at least 1.5 times placebo) are:

• Tingling sensation

• Dizziness

• Altered taste

• Insomnia

• Constipation

• Dry mouth

Most common adverse reactions in pediatric patients aged 12 years and older (incidence ≥4% and greater than placebo) are:

• Depression

• Dizziness

• Joint pain

• Fever

• Influenza

• Ligament sprain

The most common adverse reactions, reported in ≥5% of patients treated with Zepbound are:

• Nausea

• Diarrhea

• Vomiting

• Constipation

• Abdominal pain

• Indigestion

• Injection site reactions

• Fatigue

• Hypersensitivity reactions

• Belching

• Hair loss

• Gastroesophageal reflux disease (heartburn)

• Pregnancy

• Glaucoma

• Hyperthyroidism

• Taking or within 14 days of stopping monoamine oxidase inhibitors

• Known hypersensitivity to any component of Qsymia or idiosyncrasy to sympathomimetic amines

• Drug interactions: Oral contraceptives, central nervous system (CNS) depressants including alcohol, non-potassium sparing diuretics

• Personal or family history of medullary thyroid carcinoma or in patients with multiple endocrine neoplasia syndrome type 2

• Known serious hypersensitivity to tirzepatide or any of the excipients in Zepbound

• Drug interactions: Zepbound delays gastric emptying and has the potential to impact the absorption of concomitantly administered oral medications

• Embryo-fetal toxicity: Can cause fetal harm

• Increase in heart rate

• Suicidal behavior and ideation

• Risk of ophthalmologic adverse reactions

• Mood and sleep disorders

• Cognitive impairment: May cause disturbances in attention or memory, or speech/language problems

• Slowing of linear growth

• Metabolic acidosis

• Decrease in renal function

• Serious skin reactions

• Breastfeeding: Breastfeeding not recommended

• Severe gastrointestinal disease

• Acute kidney injury

• Acute gallbladder disease

• Acute pancreatitis

• Hypersensitivity reactions

• Low blood sugar: Concomitant use with an insulin secretagogue or insulin may increase the risk of low blood sugar, including severe low blood sugar

• Diabetic retinopathy complications in patients with type 2 diabetes mellitus

• Suicidal behavior and ideation

• Pregnancy: May cause fetal harm. When pregnancy is recognized, discontinue Zepbound

• Females of reproductive potential: Females using oral contraceptives should consider switching to a non-oral contraceptive method or add a barrier method of contraception for 4 weeks after initiation and for 4 weeks after each dose escalation

WARNING: RISK OF THYROID C-CELL TUMORS

In rats, tirzepatide causes thyroid C-cell tumors. It is unknown whether Zepbound causes thyroid C-cell tumors, including medullary thyroid carcinoma (MTC), in humans as the human relevance of tirzepatide-induced rodent thyroid C-cell tumors has not been determined.

Zepbound is contraindicated in patients with a personal or family history of MTC or in patients with multiple endocrine neoplasia syndrome type 2 (MEN 2). Counsel patients regarding the potential risk of MTC and symptoms of thyroid tumors.

*This information is from the label for brand name Qsymia^®. See the Full Prescribing Information for more complete information.

*This information is from the label for brand name Zepbound^®. See the Full Prescribing Information for more complete information. Tirzepatide, the active ingredient in Zepbound, may also be the active ingredient in other medications, and this information may not be accurate for all medications that include the active ingredient tirzepatide.