Drugs that Promote Weight Gain

Here are six drug classes that can promote weight gain. Please note that it is crucial you consult with your health care provider before discontinuing any prescribed medication. This is ESPECIALLY important with antidepressants and diabetes medications.

Antidepressants

A 2010 study revealed that depression patients are 58% more likely to become obese. Antidepressants like amitriptyline, nortriptyline, and paroxetine are linked to significant weight gain. Some tetracyclic antidepressants are used to promote weight gain in underweight patients and AIDS patients. Bupropion promotes weight loss and is often used for depression and smoking cessation. Contrave, a weight loss drug, is a combination of bupropion and naltrexone.

Antihistamines

50 million Americans suffer from allergies, but taking antihistamines like Zyrtec and Allegra increases their weight and insulin levels. A 2010 study found that men and women on antihistamines weighed 9.5 and 4.4 pounds more than controls due to the drugs targeting the H1 histamine receptor, which stimulates appetite.

Beta Blockers

Older beta blockers like metoprolol (Lopressor) and atenolol (Tenormin), prescribed for hypertension and heart attack prevention, can cause sluggishness, reduced motivation, and weight gain. Newer beta blockers offer weight-neutral alternatives.

Corticosteroids

When taken orally, powerful anti-inflammatory agents such as prednisone, methylprednisolone and hydrocortisone can cause insulin resistance, elevated blood glucose levels and ultimately more fat storage. Chronic oral use often leads to weight gain. Nasal sprays and oral inhalers are more weight-neutral due to their lower systemic absorption.

Diabetes Medications

Insulin is effective at stabilizing blood sugar levels for type 1 and type 2 diabetes, but frequent hypoglycemia can lead to increased body fat. Insulin is an anabolic hormone that promotes glucose, fat, and protein storage. To counter its anabolic effect, it is crucial to maintain a healthy diet and physical activity. Some older oral diabetic medications like glipizide and pioglitazone (Actos) stimulate the pancreas to secrete insulin, but may also encourage weight gain. Biguanides like metformin, SGLT-2 inhibitors like Jardiance and Farxiga, and GLP-1 agonists like semaglutide (Ozempic) and tirzepatide (Zepbound or Mounjaro) can facilitate weight loss.

Antipsychotics and Other Psychotropic Drugs

Second-generation antipsychotic drugs like olanzapine and clozapine can cause weight gain, diabetes, and elevated blood cholesterol levels, which are linked to metabolic syndrome. Patients may gain 50-60 pounds within a year of starting an antipsychotic. Aripiprazole and ziprasidone are less likely to affect body weight, blood sugar regulation, and cholesterol levels and may be used in patients with metabolic syndrome. The cause of weight gain is unclear, but people with antipsychotics have higher levels of AMP-kinase, which can block the H1 histamine receptor and boost appetite. Studies show that only 10-15% of patients receiving antipsychotics are closely monitored for metabolic syndrome.