tirzepatide (Zepbound)

General Information

Zepbound is a once-weekly injectable form of tirzepatide, a dual GIP/GLP-1 receptor agonist indicated for chronic weight management with diet and exercise (label).

It is not a psychiatric medication. In psychiatric populations it may be discussed as a metabolic risk-reduction tool (obesity and cardiometabolic risk), including in people taking weight-gain–promoting psychotropics (clinical).

Zepbound includes warnings with particular relevance to psychiatric populations: boxed warning for thyroid C-cell tumors and a warning to monitor for suicidal behavior and ideation (label).

A high-impact practical warning is reduced efficacy of oral hormonal contraceptives during initiation and dose escalation due to delayed gastric emptying; contraception counseling should be explicit and proactive (label).

The compare view, evidence feed, and print page help compare titration schedules and monitoring themes.

For psychiatric populations, feasibility often depends on coverage, follow-up capacity during titration, and coordination across prescribers. Because a warning exists for suicidal behavior/ideation, plans should include a clear monitoring and escalation pathway for new or worsening mood symptoms (label/clinical).

Mechanism of Action

Refer to the Glossary entry on Neurotransmitters for background on receptor systems involved in serious mental illness.

Tirzepatide is a dual GIP and GLP-1 receptor agonist. Clinically it supports weight reduction through incretin-based metabolic signaling, appetite effects, and delayed gastric emptying (label/clinical).

In mental health care, the practical aim is lowering metabolic risk without destabilizing psychiatric symptoms or adherence (clinical).

• Dual GIP/GLP-1 receptor agonism (incretin-based metabolic signaling).
• Appetite and satiety effects (clinical framing).

Metabolism and Pharmacokinetics

• Long half-life supports once-weekly dosing (approximately 5 days per labeling conventions).
• Major CYP-mediated interactions are not expected (peptide metabolism), but delayed gastric emptying can affect absorption of some oral drugs during initiation and dose escalation (label/clinical).

Dosing and Administration

• 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).
• If a dose is missed, administer as soon as possible within 4 days (96 hours); if more than 4 days have passed, skip the missed dose and resume the regular schedule. Do not take two doses within 3 days of each other (label).
• Injection sites include abdomen, thigh, or upper arm; rotate sites (label).
• GI tolerability often improves with slower escalation, smaller meals, and attention to hydration; severe vomiting warrants evaluation for dehydration and rare complications (clinical).

Monitoring & Labs

• 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).

Consider coordination with primary care/endocrinology for cardiometabolic monitoring and for diabetes regimen changes when applicable (clinical).

Adverse Effects

Interactions

• Oral hormonal contraceptives: advise patients to switch to a non-oral contraceptive method or add a barrier method for 4 weeks after initiation and for 4 weeks after each dose escalation (label).
• Delayed gastric emptying can affect absorption of some oral medications during titration; review narrow-therapeutic-index agents and time-sensitive regimens (clinical).

Other Useful Information

• In serious mental illness care, ensure the monitoring plan covers both metabolic response and mental health safety (especially mood changes), and that follow-up is feasible during titration (label/clinical).

References

1. ZEPBOUND (tirzepatide) injection prescribing information — DailyMed (2026)
2. Tirzepatide once weekly for the treatment of obesity — New England Journal of Medicine (2022)
3. Tirzepatide versus semaglutide once weekly in patients with type 2 diabetes — New England Journal of Medicine (2021)
4. Therapeutic Management OF Atypical Antipsychotic Related Metabolic Dysfunctions Using GLP 1 Receptor Agonists: A Systematic Review — Experimental and Therapeutic Medicine (2023)