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Zepbound (Tirzepatide) Injection Site Reactions When They Don't Go Away

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At a glance

  • Reported rate / 2% on placebo vs 6% at 5 mg, 8% at 10 mg, 8% at 15 mg [1]
  • What the label counts / Bruising, redness, itching, pain, rash at the injection site [1]
  • Expected duration / The label gives none [1]
  • Serious hypersensitivity / Anaphylaxis and angioedema reported with tirzepatide; severe hypersensitivity in 0.1% of Zepbound patients vs 0% on placebo [1]
  • Approved sites / Abdomen, thigh, back of upper arm; rotate sites [1]
  • Anti-tirzepatide antibodies / 64.5% in the weight trials, with no effect found on pharmacokinetics or effectiveness [1]

How often does Zepbound cause injection site reactions?

In the two pooled weight-management trials that support the Zepbound label (958 patients on placebo, 630 on 5 mg, 948 on 10 mg, 941 on 15 mg, treated up to 72 weeks), injection site reactions were reported in 2% of placebo patients and in 6%, 8% and 8% of patients on 5, 10 and 15 mg respectively [1].

The label groups several events under that heading: injection site bruising, erythema, pruritus, pain and rash [1]. Injection site reactions also appear on the label list of the most common adverse reactions, meaning those reported in at least 5% of Zepbound-treated patients [1]. Hypersensitivity reactions are counted separately, at 3% with placebo and 5% at each Zepbound dose [1].

What do the antibody data show?

The label reports that anti-tirzepatide antibodies were detected in 64.5% of Zepbound-treated patients in the weight trials, with no clinically significant effect on pharmacokinetics or effectiveness found [1].

A larger immunogenicity analysis across seven phase 3 trials in 5,025 patients with type 2 diabetes found treatment-emergent antibodies in 51.1% of tirzepatide-treated patients. More antibody-positive patients had hypersensitivity or injection site reactions than antibody-negative patients, but the majority of these events were nonserious and nonsevere, and most occurred or resolved irrespective of antibody status or titer [2].

Which reactions does the label treat as serious?

Serious hypersensitivity reactions, including anaphylaxis and angioedema, have been reported with tirzepatide [1]. In the pooled weight trials, 0.1% of Zepbound-treated patients had severe hypersensitivity reactions and no placebo-treated patients did [1]. Zepbound is contraindicated in people with a known serious hypersensitivity to tirzepatide or any of the excipients, and the label says to seek medical attention promptly and discontinue Zepbound if a hypersensitivity reaction occurs [1].

Do site rotation and dose strength matter?

The label says to inject in the abdomen, thigh, or back of the upper arm, with the upper-arm site given by another person, and to rotate sites [1]. It reports similar tirzepatide exposure after injections in the abdomen, thigh or upper arm [1].

Reaction rates in the weight trials were 6% at 5 mg and 8% at both 10 mg and 15 mg, against 2% on placebo [1].

Reporting a reaction

Adverse events can be reported to the FDA through MedWatch, the agency's safety reporting program for health professionals and patients [3].

Frequently asked questions

How long should a Zepbound injection site reaction last?
The label gives no expected duration. In an analysis of tirzepatide trials in type 2 diabetes, most injection site reactions were nonserious and nonsevere, and most occurred or resolved irrespective of antibody status or titer [2].
How is a local reaction different from an allergic one?
The label groups bruising, redness, itching, pain and rash under injection site reactions, and reports hypersensitivity reactions separately: 5% at every Zepbound dose versus 3% on placebo, with severe hypersensitivity in 0.1% versus none [1]. Serious hypersensitivity reactions, including anaphylaxis and angioedema, have been reported with tirzepatide [1].
Does rotating injection sites help?
The label says to rotate injections among the abdomen, thigh and back of the upper arm, and that another person should give an upper-arm injection. It also reports similar tirzepatide exposure after injections at the three sites [1].
Are injection site reactions more common at higher doses?
In the pooled weight trials the rate was 6% at 5 mg and 8% at both 10 mg and 15 mg, against 2% on placebo [1].
What does the label say to do about a reaction that will not go away?
The label gives no instruction specific to a persistent local reaction. Its stop instruction is tied to hypersensitivity: seek medical attention promptly and discontinue Zepbound if a hypersensitivity reaction occurs [1].

References

  1. U.S. National Library of Medicine, DailyMed. Zepbound injection (tirzepatide) prescribing information. Zepbound injection (tirzepatide) label
  2. Mullins GR, Hodsdon ME, Li YG, Anglin G, Urva S, Schneck K, et al. Tirzepatide Immunogenicity on Pharmacokinetics, Efficacy, and Safety: Analysis of Data From Phase 3 Studies. J Clin Endocrinol Metab. 2024;109(2):361-369. Tirzepatide Immunogenicity on Pharmacokinetics, Efficacy, and Safety: Analysis of Data From Phase 3 Studies
  3. MedWatch: The FDA Safety Information and Adverse Event Reporting Program | FDA. MedWatch: The FDA Safety Information and Adverse Event Reporting Program | FDA
Evidence overview for Zepbound (Tirzepatide) Injection Site Reactions When They Don't Go Away