tirzepatide (Zepbound)

General information

• Primary label indications include: Chronic weight management (with diet and exercise) in adults with obesity or overweight with weight-related comorbidities (label).
• Class: Adjunctive therapy
• Common US brands: ZEPBOUND
• Typical dose range: Typical: titrate to a maintenance dose of 5 mg, 10 mg, or 15 mg subcutaneously once weekly (start 2.5 mg once weekly for 4 weeks; increase in 2.5 mg steps after at least 4 weeks at each dose) (label).
• Therapeutic drug monitoring not routinely recommended.
• Last reviewed: 2026-02-12

Dosing & forms

• Forms/strengths: Single-dose pens for subcutaneous injection once weekly (label).; Dose strengths include 2.5 mg through 15 mg pens (label).
• Frequency: Typical: titrate to a maintenance dose of 5 mg, 10 mg, or 15 mg subcutaneously once weekly (start 2.5 mg once weekly for 4 weeks; increase in 2.5 mg steps after at least 4 weeks at each dose) (label).
• Typical range: Typical: titrate to a maintenance dose of 5 mg, 10 mg, or 15 mg subcutaneously once weekly (start 2.5 mg once weekly for 4 weeks; increase in 2.5 mg steps after at least 4 weeks at each dose) (label).

Mechanism (brief)

Weekly injectable dual [[GIP]]/[[GLP-1]] receptor agonist (tirzepatide) indicated for chronic weight management (with diet and exercise). It has no FDA-approved psychiatric indications but may be considered in psychiatric populations for cardiometabolic risk reduction with careful monitoring for mood changes (label/clinical).

Metabolism & Half‑life

• Metabolism: Proteolytic cleavage of the peptide backbone
• Half‑life: Single-dose mean 120 h

Therapeutic Drug Monitoring (TDM)

Recommended: No

Monitoring highlights

• Weight/BMI and waist circumference trend; document baseline and track response over time (clinical).
• Monitor for new or worsening depression, suicidal thoughts/behaviors, and unusual mood changes; discontinue if symptoms develop (label).
• Monitor for symptoms of pancreatitis and gallbladder disease (persistent severe abdominal pain, vomiting) (label).
• Monitor for dehydration and renal function concerns when significant GI losses occur (label/clinical).
• Contraception counseling for patients using oral hormonal contraceptives during initiation and dose escalation (label).

Sources

• ZEPBOUND (tirzepatide) injection prescribing information — DailyMed (2026)
• Tirzepatide once weekly for the treatment of obesity — New England Journal of Medicine (2022)
• Tirzepatide versus semaglutide once weekly in patients with type 2 diabetes — New England Journal of Medicine (2021)
• Therapeutic management of atypical antipsychotic-related metabolic dysfunctions using GLP-1 receptor agonists: a systematic review — Experimental and Therapeutic Medicine (2023)