ZEPBOUND
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ZEPBOUND (ZEPBOUND).
Tirzepatide is a glucose-dependent insulinotropic polypeptide (GIP) receptor and glucagon-like peptide-1 (GLP-1) receptor dual agonist. It binds to and activates both GIP and GLP-1 receptors, leading to increased insulin secretion, decreased glucagon secretion, slowed gastric emptying, and increased satiety, resulting in improved glycemic control and weight loss.
| Metabolism | Tirzepatide is metabolized via proteolytic cleavage of the peptide backbone, beta-oxidation of the fatty diacid moiety, and amide hydrolysis. It does not significantly involve CYP450 enzymes. Metabolites are excreted primarily in urine and feces. |
| Excretion | Renal elimination of intact peptide (urine) and proteolytic degradation (fecal/biliary). Following subcutaneous administration, approximately 70% of the dose is excreted renally as intact tirzepatide and 30% via feces as metabolites. |
| Half-life | Terminal elimination half-life is approximately 5 days (range 4–6 days), supporting once-weekly dosing. Steady state is achieved after 4 weeks of once-weekly administration. |
| Protein binding | Tirzepatide is highly bound to albumin (approximately 99%). |
| Volume of Distribution | Volume of distribution is approximately 10.3 L (0.13 L/kg for a 70 kg individual), indicating limited extravascular distribution, primarily confined to plasma and interstitial fluid. |
| Bioavailability | Subcutaneous: Absolute bioavailability is approximately 80% following abdominal administration. Bioavailability is similar for injection sites (abdomen, thigh, upper arm). |
| Onset of Action | Subcutaneous: Onset of glucose lowering occurs within 2–3 hours after first dose, with peak effect on postprandial glucose at 4–6 hours. Weight loss onset is variable but typically observed within 2–4 weeks. |
| Duration of Action | Duration of glucose-lowering effect extends beyond the dosing interval (≥7 days) due to long half-life. Clinical effects on HbA1c and weight are sustained with continued weekly dosing. |
| Molecular Weight | 4815.5 |
Subcutaneously once weekly; initial dose 2.5 mg for 4 weeks, then increase to 5 mg; if additional glycemic control needed, may increase in 2.5 mg increments after at least 4 weeks on current dose, up to maximum 15 mg once weekly.
| Dosage form | SOLUTION |
| Renal impairment | No dose adjustment required for mild to moderate renal impairment (eGFR ≥30 mL/min/1.73 m²). Not recommended in severe renal impairment (eGFR <30 mL/min/1.73 m²) or end-stage renal disease. |
| Liver impairment | No dose adjustment required for mild hepatic impairment (Child-Pugh class A). Not recommended for moderate or severe hepatic impairment (Child-Pugh class B or C). |
| Pediatric use | Not approved for use in pediatric patients; safety and efficacy not established. |
| Geriatric use | No dose adjustment required based on age alone; consider renal function and comorbidities; limited experience in patients aged ≥75 years. |
| 1st trimester | No adequate human data; animal studies show risk of fetal harm at exposures similar to human doses at maximum recommended dose. Based on mechanism, potential for harm in human pregnancy. Avoid use. |
| 2nd trimester | No human data; animal studies suggest risk. Due to prolonged half-life, exposure may continue after discontinuation. Avoid use. |
| 3rd trimester | No human data; theoretical risk of fetal hypoglycemia and growth abnormalities. Avoid use. |
Clinical note
Comprehensive clinical and safety monograph for ZEPBOUND (ZEPBOUND).
| Placental transfer | High molecular weight suggests limited placental transfer; however, as a peptide, it may cross by pinocytosis or other mechanisms. Animal studies show detectable levels in fetal plasma. Human data absent. |
| Breastfeeding | Tirzepatide is present in rat milk; unknown if excreted in human milk. No data on effects on milk production or infant. Due to potential for adverse reactions (e.g., hypoglycemia), breastfeeding is not recommended during treatment and for at least 6 weeks after last dose. |
■ FDA Black Box Warning
No FDA boxed warning.
| Serious Effects |
Personal or family history of medullary thyroid carcinoma (MTC)Multiple endocrine neoplasia syndrome type 2 (MEN 2)Known serious hypersensitivity to tirzepatide or any excipient
| Precautions | Risk of thyroid C-cell tumors (medullary thyroid carcinoma); contraindicated in patients with a personal or family history of MTC or MEN 2, Acute pancreatitis: discontinue if suspected, Hypoglycemia, especially when used with insulin or sulfonylureas, Renal impairment (acute kidney injury reported, may worsen chronic kidney disease), Gastrointestinal effects (nausea, vomiting, diarrhea) may lead to dehydration, Diabetic retinopathy complications reported (not established), Hypersensitivity reactions (angioedema, anaphylaxis), Accelerated growth of pre-existing gastrointestinal neoplasms (caution in patients with history of GI neoplasms) |
| Food/Dietary | ZEPBOUND delays gastric emptying, which may affect absorption of oral medications, especially those requiring rapid therapeutic levels (e.g., antibiotics, oral contraceptives). Administer oral contraceptives at least 4 hours prior to tirzepatide injection or consider alternative contraception. No specific dietary restrictions are required, but a low-fat diet may reduce gastrointestinal side effects. Avoid high-fat meals as they can exacerbate nausea and vomiting. Alcohol consumption may increase the risk of hypoglycemia and gastrointestinal distress. |
Loading safety data…
| Lactation Rating | Avoid (No data, potential risk) |
| Teratogenic Risk | Tirzepatide (Zepbound) is contraindicated during pregnancy due to potential fetal harm based on animal studies showing reduced fetal growth and skeletal anomalies. Risk in first trimester: insufficient human data; animal data suggest risk. Second/third trimester: adverse fetal outcomes (e.g., oligohydramnios, fetal death) seen in animal studies. No adequate human studies. |
| Fetal Monitoring | Monitor women of childbearing potential for pregnancy status before initiation and during treatment. Advise effective contraception. If pregnancy occurs, discontinue immediately and monitor for fetal outcomes via ultrasound (e.g., growth, amniotic fluid). No standard protocol; clinical monitoring per obstetrical care. |
| Fertility Effects | Animal studies show no impairment of fertility; human data limited. May affect female fertility via weight loss and metabolic changes; caution in women planning pregnancy. |
| Clinical Pearls | ZEPBOUND (tirzepatide) is a once-weekly GIP/GLP-1 receptor agonist for type 2 diabetes and chronic weight management. Dose titration is essential: start at 2.5 mg weekly for 4 weeks, then increase by 2.5 mg increments every 4 weeks to a maximum of 15 mg weekly. Gastrointestinal adverse effects (nausea, vomiting, diarrhea) are common; prescribe antiemetics and encourage small, frequent meals. Administer subcutaneously in the abdomen, thigh, or upper arm, rotating sites. Monitor for pancreatitis, gallbladder disease, and suicidal ideation. Renal dose adjustment not required, but use caution in severe renal impairment. Avoid in personal or family history of medullary thyroid carcinoma (MTC) or Multiple Endocrine Neoplasia syndrome type 2 (MEN-2). |
| Patient Advice | ZEPBOUND is injected once weekly on the same day each week, with or without meals. · Start with a low dose and gradually increase as directed to reduce stomach upset. · Common side effects include nausea, diarrhea, vomiting, and constipation; these often improve over time. · Seek immediate medical attention for severe abdominal pain, rash, difficulty swallowing, or vision changes. · Do not share pens or needles; store unopened pens in refrigerator (36°F to 46°F) and opened pens at room temperature for up to 28 days. · Tell your doctor if you are pregnant, breastfeeding, or planning to conceive; ZEPBOUND may cause fetal harm. · Report any symptoms of pancreatitis (persistent severe abdominal pain, vomiting) or gallbladder disease (right upper quadrant pain, fever). · Do not use if you or your family have had medullary thyroid carcinoma or MEN-2 syndrome. · Monitor blood glucose as directed; ZEPBOUND can lower blood sugar levels, especially when combined with insulin or sulfonylureas. · Maintain adequate hydration to prevent constipation and kidney issues. |