Mounjaro (trade name of Tirzepatide) is an FDA (May 2022) approved prescription drug which is currently available solely in an injectable form. It is currently employed as the second line diabetes medication to improve hyperglycaemia in individuals with type 2 diabetes mellitus and weight loss in obese individuals when supplemented with a healthy diet and lifestyle.

Pharmacological mechanism

Tirzepatide is a synthetic peptide which mimics the dual action of the natural incretin hormones:

1. Glucose-dependent Insulinotropic polypeptide (GIP)
   
   
2. Glucagon like-peptide-1 receptor agonist (GLP-1 RA)
   
   

GIP and GLP-1 RA are released in the gut in response to the nutrients present in the food. They help:

• The pancreas release insulin in response to hyperglycaemia (high levels of blood sugar). It lowers fasting and postprandial blood glucose levels. 
  
  
• Helps decrease appetite and improve satiety.
  
  
• Retards gastric motility (decreases rate in which food leaves the stomach). This helps delay the postprandial glucose absorption.
  
  
• Inhibits glycogenolysis (release of glucose from the liver)
  
  
• Reduces body weight – Mounjaro may result in weight loss in diabetic individuals.
  
  

5 trials were conducted on individuals with type 2 diabetes mellitus. They were given 5-15mg of Tirzepatide per week. Majority of patients had reductions in HbA1c (1.24-2.58%) and body weight (5.4-11.7kg).

A clinical trial conducted exhibited the beneficial effects of tirzepatide by reducing Body Mass Index (BMI) and a reduction in body weight by 20% more efficiently in comparison to the older weight loss drugs available in the market.

An individual may be suitable to be given Mounjaro (tirzepatide) if they fall under the following category which is similar to the eligibility of Wegovy:

• BMI – > 30 kg/m2 
  
  
• BMI – 27 – 30 kg/m2 with 1 weight related medical condition (comorbidities – diabetes, hypertension, hyperlipidaemia, obstructive sleep apnoea (OS), heart attack, stroke, and blood vessel disorders)
  
  
• Adolescents who are above 12 years of age with a BMI > 95th percentile or weighing above 60kg.
  
  

However, the lower BMI threshold is used for individuals of South Asian, Chinese, other Asian, Middle Eastern, Black African or African Caribbean family backgrounds. The BMI is reduced by 2.5 kg/m2.

Use and contraindications in specific demographics

Mounjaro may be prescribed to adults with type 2 DM. 

• There isn’t sufficient information regarding the use of tirzepatide in the treatment of Individuals with type 1 diabetes.
  
  
• Children below 18 years of age.
  
  
• Pregnant and lactating mothers.
  
  
• Individuals with a history of pancreatitis.
  
  

Contraindications

Tirzepatide is contraindicated in individuals with

• Hypersensitivity to ingredients of Mounjaro or tirzepatide in specific.
  
  
• Individuals who have a genetic and family history of medullary thyroid carcinoma (MTC) or multiple endocrine neoplasia syndrome type 2 (MEN 2).
  
  

Warnings

Trials conducted revealed the following risks:

• Thyroid C-Cell tumours – This was seen in trials of animal models only. Mounjaro may lead to thyroid tumours. Symptoms are – lump/swelling of the neck, hoarseness, difficulty swallowing, shortness of breath). No human cases have been reported as far as we know.
  
  
• Pancreatitis – Insistent abdominal pain, with or without vomiting. Seek urgent medical help.
  
  
• Hypoglycaemia – Low blood sugar levels may be accompanied by symptoms such as – dizziness, headache, sweating, confusion, hunger, weakness, jitters, blurry vision, slurred speech, anxiety, rapid heart rate etc. The possible reason for this can be attributed to combination of tirzepatide with other drugs like insulin or sulphonylurea.
  
  
• Hypersensitivity – Allergy to any of the constituents of tirzepatide may be manifested on the face, lips, tongue or throat.
  
  
• Acute kidney injury – Tirzepatide may worsen renal conditions.
  
  
• Gastrointestinal issues
  
  
• Diabetic retinopathy
  
  
• Acute gallbladder disease – Cholelithiasis, cholecystitis, biliary colic, cholecystectomy, Jaundice or clay coloured stools are common possible complications.
  
  

Side effects

The side effects of tirzepatide are similar to those induced by GLP-1 RA. The intensity of the side effect depends on the dosage of Mounjaro (trizepatide)

• Nausea and vomiting
• Diarrhoea 
• Decreased appetite 
• Gastroesophageal reflux 
• Abdominal pain
• Bloating
• Belching
• Constipation
• Fatigue
• Hypoglycaemia
• Vivid dreams
• Hair loss
  
  

Tips to manage side effects

• Eat small quantity meals.
  
  
• Avoid fatty, fried and spicy food.
  
  
• Consume plenty of fluids. 
  
  
• Consult a dietitian for dietary advice.
  
  
• Restrict consumption of alcohol and caffeine.
  
  
• Have meals few hours prior to bedtime.
  
  
• Foods like ginger, carom seeds etc., can help with bloating.
  
  
• Stay physically active.
  
  
• Consume plenty of fruits and vegetables rich in fibre.
  
  
• Improve sleep quality and hygiene.
  
  

How to use Mounjaro (tirzepatide)?

• Mounjaro is administered subcutaneously through an injection. There is no oral dose available currently. 
  
  
• It is available in varied dosages – 2.5mg/0.5mL, 5mg/0.5mL, 7.5mg/0.5mL, 10mg/0.5mL, 12.5mg/0.5mL, 15mg/0.5mL.
  
  
• The dose of Mounjaro may be titrated after 4 weeks from 2.5mg to 5mg. Further titration may be based on individual tolerance.
  
  
• Mounjaro must be used as per a registered medical practitioner’s advice.
  
  
• It is injected subcutaneously under the skin of the abdomen, thigh or back of the upper arm.
  
  
• The frequency of use of once a week at any time of the day.
  
  
• The site of subcutaneous injection must be alternated every week.
  
  
• Dispose your pens after use according to the community guidelines.
  
  
• Mounjaro must be stored between 2-8 degree Celsius. 
  
  

Note

• Mounjaro must not be reconstituted with insulin in the same injection 
  
  
• The area of injecting Mounjaro and insulin may be the same are of the body but next to each other
  
  
• The minimum duration of gap between 2 doses of Mounjaro must be 72 hours. The day of injection can change per week based on this.
  
  
• A missed dose of Mounjaro can be taken on the regular scheduled day if 4 days have passed.
  
  
• Always consult a physician before starting Mounjaro (tirzepatide).