According to the notification published on 8 Nov 2023, the United States Food and Drug Administration (US-FDA) has authorized Tirzepatide injection, marking a milestone in the realm of chronic weight management for adults grappling with obesity or overweight. This approval is targeted at individuals with a body mass index (BMI) of 30 kg/m² or greater for obesity, or a BMI of 27 kg/m² or greater for overweight, coupled with at least one weight-related condition such as elevated blood pressure, type 2 diabetes, or elevated cholesterol.

Tirzepatide is intended for usage in conjunction with a decreased-calorie diet and elevated physical activity. Obesity and overweight are grave ailments that can be linked with some of the major triggers of death like diabetes, heart disorder, and stroke. About 70% of American adults contend with overweight or obesity, often accompanied by weight-associated conditions. Scientific evidence supports the idea that a 5% to 10% abatement in body weight through diet and exercise can considerably diminish the hazard of cardiovascular illness in this population.

The medication operates by invigorating receptors of hormones (glucose-dependent insulinotropic polypeptide [GIP] and glucagon-like peptide-1 [GLP-1]) secreted from the intestine. This mechanism effectively curbs appetite and diminishes food intake. Given through weekly injections under the skin, the dose is gradually raised over four to twenty weeks to attain target doses of 5 mg, 10 mg, or 15 mg once weekly, with 15 mg being the maximum dose. Tirzepatide has proven to be effective for the long-term management of weight in individuals battling obesity or overweight, coupled with a reduced-calorie diet and increased physical activity.

This conclusion stemmed from two randomized trials involving subjects having obesity or overweight and at least one weight-connected ailment. The trials, which spanned 72 weeks and included a total of 2,519 volunteers receiving 5 mg, 10 mg, or 15 mg of Tirzepatide once weekly, as well as 958 volunteers receiving once-weekly placebo injections, demonstrated a remarkable drop in body weight for those on Tirzepatide at all three dose levels compared to the placebo group.  Moreover, a higher percentage of patients in the Tirzepatide group attained at least a 5% weight reduction compared to those in the placebo group.

The more extensive of the two studies focused on subjects without diabetes, with an average BMI of 38 kg/m2 and an initial average body weight of 231 pounds (105 kg). Participants getting 15 mg once weekly Tirzepatide (the highest approved dose) experienced an average weight loss of 18% in comparison with the placebo arm. In the trial involving adults with type 2 diabetes, who started with a mean body weight of 222 pounds (101 kg) and a mean BMI of 36 kg/m2, those randomly allocated to the highest approved Tirzepatide dosage (15 mg once weekly) exhibited a mean weight loss of 12% in comparison with their counterparts on placebo.

Tirzepatide may lead to various side effects, including but not limited to constipation, nausea, vomiting, diarrhea, abdominal discomfort and pain, injection site reactions, burping, fatigue, hypersensitivity reactions (usually characterized by rash and fever), hair loss, and gastroesophageal reflux disease (GERD). Of particular concern are thyroid C-cell tumors observed in rats, raising questions about the potential impact on humans. Consequently, the medication is not recommended to be used in those having a family or personal history of medullary thyroid cancer or multiple endocrine neoplasia syndrome type 2. While this FDA sanction is a positive step forward in addressing the obesity epidemic, caution is advised.

Tirzepatide must not be used in those having a history of serious allergic reactions to Tirzepatide, pancreatitis, or grave gastrointestinal illness. Additionally, it must not be used in combination with GLP-1 receptor agonist or Mounjaro, and its safety when coadministered with other agents for weight control remains unestablished. Tirzepatide underwent Priority Review and Fast Track designations, underscoring the urgency and significance of this breakthrough in chronic weight management. Patients are requested to consult with their medical care personnel to discuss potential risks and benefits prior to commencing Tirzepatide therapy.