Qsymia Vs. Mounjaro: 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.

Mounjaro^® (tirzepatide) is an injectable medication used to treat type 2 diabetes by improving blood sugar control and promoting weight loss. It functions by activating two receptors, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), which enhance insulin secretion and slow gastric emptying. Mounjaro is administered once weekly, with dose adjustments made based on the patient's response. Common side effects include nausea, diarrhea, and decreased appetite. It should be used with caution in individuals with a history of thyroid cancer or multiple endocrine neoplasia syndrome type 2​.

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

Mounjaro (tirzepatide) is indicated:

• As an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus

• 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 Mounjaro are:

• Nausea

• Diarrhea

• Decreased appetite

• Vomiting

• Constipation

• Indigestion

• Abdominal pain

• 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 Mounjaro

• Drug interactions: Mounjaro 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

• Pancreatitis

• Low blood sugar with concomitant use of insulin secretagogues or insulin

• Hypersensitivity reactions

• Acute kidney injury

• Severe gastrointestinal disease

• Diabetic retinopathy complications in patients with a history of diabetic retinopathy

• Acute gallbladder disease

• Pregnancy: Based on animal study, may cause fetal harm

• 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

Tirzepatide causes thyroid C-cell tumors in rats. It is unknown whether Mounjaro 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.

Mounjaro 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 Mounjaro. See the Full Prescribing Information for more complete information. Tirzepatide, the active ingredient in Mounjaro, 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.