Weight loss can be a life-changing journey and sometimes we need the help of medications to embark on this path. Wegovy and Mounjaro are both weight loss injections used for weight loss in addition to exercise and diet. 

Wegovy 

This medication’s active ingredient is semaglutide and belongs to the class of GLP-1 receptor agonists. Wegovy is approved for chronic weight management in adults with obesity or those who are overweight with other medical conditions.

It works by mimicking the GLP-1 hormones that regulate appetite and blood sugar. This leads to reduced hunger and increased satiety. Wegovy is a weekly injection with a dosage ranging from 0.25 to 2.4mg. 

Mounjaro

This medication’s active ingredient is tirzepatide, which is a dual receptor agonist. It is approved for type 2 diabetes and weight management. It combines GLP-1 effects with GIP which enhances weight loss and glycemic control. Mounjaro is a weekly injection with doses titrated from 2.5mg up to 15mg. 

Changing from Wegovy to Mounjaro

The transition from Wegovy to Mounjaro can be for various reasons. Sometimes one medication alone may not provide the desired effects hence trialing of different medications is required. 

Enhanced weight loss

Clinical trials have suggested that Mounjaro may offer greater weight loss than Wegovy. This is due to its dual action mechanism. The highest dose is 15mg providing individuals with options to choose a maintenance dose anywhere from 7.5mg to 15mg. 

It is important to note that weight loss results on both these medications can vary. Each person has a different body composition so one medication that may work wonders for one may not be effective for another.

Side effect profile

Most injectable weight loss medications have similar side effects due to the way they work. However, some patients may tolerate Mounajro better or experience fewer gastrointestinal side effects than Wegovy. The one side effect that differs between the two, is that in Mounjaro women of childbearing age must use contraception. Wegovy use during pregnancy is not recommended. 

Steps to Switch to Mounjaro

When you want to switch medication, the first step should always be to involve your doctor. They will evaluate your medical history, and health goals to ensure the best outcome to lose weight. 

Discontinue Wegovy

The Wegovy dose cycle must be completed before starting Mounjaro. This is to avoid overlapping effects or side effects of medication. The doctor may suggest a washout period. This is a period of waiting between the two medications and depends on individual tolerance and medical conditions. 

Initiate Mounjaro

When we initiate Mounjaro, start at the lowest dose (2.5mg weekly) to minimise side effects. Then gradually titrate up according to the prescribed schedule to achieve therapeutic benefits.

Side Effects

Common side effects of both drugs include nausea, vomiting, and diarrhoea. Side effects like hypoglycemia, gallbladder issues, injection site reactions, fatigue, and dizziness are more common in Mounjaro than in Wegovy. In this transition time, monitor the symptoms and communicate with the doctor if they worsen. 

It is possible to experience a rare or allergic reaction to these medicines. Please read the patient information leaflet for a full list of side effects for Wegovy and Mounjaro.

Challenges when switching

When switching from Wegovy to Mounjaro your doctor may recommend a period where the medication is without both medications. The need or exact duration of the washout period will depend on individual factors such as the dose of Wegovy and other medical conditions. 

Wegovy has a long half-life of 7 days meaning it can take 4-5 weeks for the drug to completely cleat from the system. In most cases, doctors may only recommend a washout period of 1-2 weeks to avoid overlapping side effects. 

If you are on a low dose of Wegovy (less than 1mg) you stop treatment for 2 weeks before commencing Mounjaro. On the higher doses, the treatment may need a gap of 4 weeks before beginning Mounjaro. When starting Mounjaro, titrate the dose from the lowest strength. 

The switching of medicines should always be under the supervision of a doctor. They can best assess the risk of side effects and your reduction dosage schedule based on your health status. 

Consult a doctor