ZEPBOUND (AUTOINJECTOR)

Clinical safety rating: caution

Comprehensive clinical and safety monograph for ZEPBOUND (AUTOINJECTOR) (ZEPBOUND (AUTOINJECTOR)).

How it works

Tirzepatide is a dual agonist of GLP-1 and GIP receptors, enhancing insulin secretion, delaying gastric emptying, and reducing appetite and food intake.

What the body does with it

Metabolism	Metabolized via proteolytic cleavage of the peptide backbone, with some involvement of peptidases and possibly CYP enzymes (minor). Excreted primarily as metabolites in urine and feces.
Excretion	Primarily renal excretion of intact tirzepatide (approximately 50-60% of the dose) and minor biliary/fecal excretion (<10%). The remainder is metabolized via proteolysis into small peptides and amino acids.
Half-life	Terminal elimination half-life is approximately 5 days (range 4-6 days) following subcutaneous administration, supporting once-weekly dosing. Steady-state is achieved after 4 weeks of weekly dosing.
Protein binding	Highly bound to albumin (approximately 99%).
Volume of Distribution	Central volume of distribution (Vc) is approximately 4.2 L (0.06 L/kg for a 70 kg individual), indicating limited tissue distribution and primarily confinement to the vascular space.
Bioavailability	Subcutaneous: Absolute bioavailability is approximately 80% (range 70-90%) relative to intravenous administration. Oral bioavailability is negligible (<1%) due to peptide degradation and poor permeability.
Onset of Action	Subcutaneous: Onset of glucose-lowering effects is observed within 1-2 hours, with maximal effects on postprandial glucose at 4-6 hours. Weight loss effects are gradual, typically evident within 2-4 weeks.
Duration of Action	Duration of action is approximately 7 days, consistent with once-weekly dosing. Pharmacodynamic effects on glucose and body weight persist for at least 7 days after the last dose, with gradual return to baseline over several weeks.

Classification & Brands

Dosing & administration

Subcutaneous injection once weekly. Initial dose 2.5 mg; after 4 weeks increase to 5 mg. Continue 5 mg for at least 4 weeks; if additional glycemic control needed, increase in 2.5 mg increments at 4-week intervals to a maximum dose of 15 mg once weekly.

Dosage form	SOLUTION
Renal impairment	No dose adjustment required for mild to moderate renal impairment (eGFR ≥15 mL/min/1.73 m²). Not recommended in end-stage renal disease (eGFR <15 mL/min/1.73 m²) due to lack of data.
Liver impairment	No dose adjustment required for mild to moderate hepatic impairment (Child-Pugh class A and B). Not studied in severe hepatic impairment (Child-Pugh class C); use with caution.
Pediatric use	Safety and efficacy not established in pediatric patients (<18 years). No dosing recommendations available.
Geriatric use	No dose adjustment required solely based on age. Consider renal function and potential for increased sensitivity; initiate at lowest dose and titrate cautiously.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for ZEPBOUND (AUTOINJECTOR) (ZEPBOUND (AUTOINJECTOR)).

Breastfeeding	No human data on excretion in breast milk. Tirzepatide is a large peptide and likely enters milk minimally; unknown effects on infant. Caution recommended. M/P ratio: not determined.
Teratogenic Risk	Tirzepatide (Zepbound) is a GLP-1/GIP receptor agonist. Based on animal studies, there is a risk of fetal harm. Limited human data; advise avoiding in pregnancy. First trimester: potential for malformations. Second/third trimester: risk of fetal growth abnormalities and neonatal hypoglycemia if used near term.

Warnings & precautions

■ FDA Black Box Warning

Risk of thyroid C-cell tumors. Tirzepatide is contraindicated in patients with a personal or family history of medullary thyroid carcinoma (MTC) or in patients with Multiple Endocrine Neoplasia syndrome type 2 (MEN 2).

Side Effect Profile

Serious Effects

Absolute Contraindications

["Personal or family history of medullary thyroid carcinoma (MTC)","Multiple Endocrine Neoplasia syndrome type 2 (MEN 2)","Hypersensitivity to tirzepatide or any components"]

Clinical Precautions

Precautions

["Pancreatitis: Discontinue if suspected; avoid if history of pancreatitis.","Hypoglycemia: Monitor blood glucose, especially when used with insulin or insulin secretagogues.","Acute kidney injury: Monitor renal function in patients with renal impairment.","Gastrointestinal effects: May cause nausea, vomiting, diarrhea; adjust dose as needed.","Hypersensitivity reactions: Discontinue if anaphylaxis or angioedema occurs.","Diabetic retinopathy: Monitor for worsening in patients with history of retinopathy."]

Clinical Tips & Counseling

Drug interactions

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ZEPBOUND (AUTOINJECTOR)

Clinical safety rating: caution

Comprehensive clinical and safety monograph for ZEPBOUND (AUTOINJECTOR) (ZEPBOUND (AUTOINJECTOR)).

How it works

Tirzepatide is a dual agonist of GLP-1 and GIP receptors, enhancing insulin secretion, delaying gastric emptying, and reducing appetite and food intake.

What the body does with it

Metabolism	Metabolized via proteolytic cleavage of the peptide backbone, with some involvement of peptidases and possibly CYP enzymes (minor). Excreted primarily as metabolites in urine and feces.
Excretion	Primarily renal excretion of intact tirzepatide (approximately 50-60% of the dose) and minor biliary/fecal excretion (<10%). The remainder is metabolized via proteolysis into small peptides and amino acids.
Half-life	Terminal elimination half-life is approximately 5 days (range 4-6 days) following subcutaneous administration, supporting once-weekly dosing. Steady-state is achieved after 4 weeks of weekly dosing.
Protein binding	Highly bound to albumin (approximately 99%).
Volume of Distribution	Central volume of distribution (Vc) is approximately 4.2 L (0.06 L/kg for a 70 kg individual), indicating limited tissue distribution and primarily confinement to the vascular space.
Bioavailability	Subcutaneous: Absolute bioavailability is approximately 80% (range 70-90%) relative to intravenous administration. Oral bioavailability is negligible (<1%) due to peptide degradation and poor permeability.
Onset of Action	Subcutaneous: Onset of glucose-lowering effects is observed within 1-2 hours, with maximal effects on postprandial glucose at 4-6 hours. Weight loss effects are gradual, typically evident within 2-4 weeks.
Duration of Action	Duration of action is approximately 7 days, consistent with once-weekly dosing. Pharmacodynamic effects on glucose and body weight persist for at least 7 days after the last dose, with gradual return to baseline over several weeks.

Classification & Brands

Dosing & administration

Dosage form	SOLUTION
Renal impairment	No dose adjustment required for mild to moderate renal impairment (eGFR ≥15 mL/min/1.73 m²). Not recommended in end-stage renal disease (eGFR <15 mL/min/1.73 m²) due to lack of data.
Liver impairment	No dose adjustment required for mild to moderate hepatic impairment (Child-Pugh class A and B). Not studied in severe hepatic impairment (Child-Pugh class C); use with caution.
Pediatric use	Safety and efficacy not established in pediatric patients (<18 years). No dosing recommendations available.
Geriatric use	No dose adjustment required solely based on age. Consider renal function and potential for increased sensitivity; initiate at lowest dose and titrate cautiously.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for ZEPBOUND (AUTOINJECTOR) (ZEPBOUND (AUTOINJECTOR)).

Breastfeeding	No human data on excretion in breast milk. Tirzepatide is a large peptide and likely enters milk minimally; unknown effects on infant. Caution recommended. M/P ratio: not determined.
Teratogenic Risk	Tirzepatide (Zepbound) is a GLP-1/GIP receptor agonist. Based on animal studies, there is a risk of fetal harm. Limited human data; advise avoiding in pregnancy. First trimester: potential for malformations. Second/third trimester: risk of fetal growth abnormalities and neonatal hypoglycemia if used near term.

Warnings & precautions

■ FDA Black Box Warning

Side Effect Profile

Serious Effects

Absolute Contraindications

["Personal or family history of medullary thyroid carcinoma (MTC)","Multiple Endocrine Neoplasia syndrome type 2 (MEN 2)","Hypersensitivity to tirzepatide or any components"]