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What are some medications that cause weight gain?

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Which medications?Managing weight gainSummary
Besides being a frustrating side effect, weight gain from medications may increase the risk of other health conditions. You can talk with a doctor about switching drugs or other ways to help manage your weight.
Medically reviewed by Alyssa Walton, PharmD
Written by Faye Stewart
Updated on

Starting a new medication, whether for managing symptoms of depression, lowering blood pressure, or helping with allergies, can lead to weight gain as a side effect.

Some medications may cause a small weight increase, but others can lead to much more, which you might find offputting.

However, there are ways to manage weight gain due to medication.

Medications more likely to cause weight gain

Overhead view of adult female sitting on a chair in a sitting room with a laptop on a coffee table surrounded by some prescription medications and a coffee mug. There is a medical professional on the laptop screen and she could be on a video call with them discussing medications that cause weight gain.
Photography by SrdjanPav/Getty Images

Hormones create and release chemical messengers that tell your body what to do and when. This process affects many functions, including metabolism, sleep, blood pressure, and mood.

Your glands can increase or decrease “hormone traffic” based on your specific needs. But when you take a medication that changes hormone levels, the glands can get confused and may begin to control hormone traffic differently. The confusion can create some symptoms, like weight gain.

“To make things even more complicated, not all medication-related weight gain happens right away,” said Daniel Breisch, PharmD, a pharmacist at Mountain View Pharmacy in Bountiful, Utah. “With some medications, people will notice an initial gain, which will then taper off, while other drugs have a cumulative effect and may take 6 months before the person notices substantial weight gain.”

Here, we look at some of the most common medications that can have weight gain as a side effect.


Antidepressants work to balance brain chemicals and lessen the symptoms of mental health conditions. They can also help improve mood, and many include weight gain as a side effect.

Doctors and healthcare professionals most commonly prescribe antidepressants called selective serotonin reuptake inhibitors (SSRIs). These medications increase the brain chemical serotonin, which also plays a role in how hungry you feel. Common examples of SSRIs are:

Another class of antidepressants called tricyclic antidepressants (TCAs) may have a higher chance of causing weight gain. This is because they affect serotonin and norepinephrine. Norepinephrine is another brain chemical, and it lets you know when you’re full. Examples of TCAs include amitriptyline and amoxapine.


Doctors and healthcare professionals use antipsychotic medications to treat conditions like bipolar disorder and schizophrenia.

Antipsychotics such as olanzapine (Zyprexa) can slow down how your body processes sugars and fats, leading to weight gain. They can also have a sedating effect that may disrupt exercise routines.


Histamine is the chemical responsible for allergies. It also plays a role in reducing hunger. Medications that lower histamine levels could increase your appetite and, over time, lead to weight gain.

Taking diphenhydramine (Benadryl) or loratadine (Claritin) occasionally will not lead to weight gain, but you may notice a weight increase with longer-term use.

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Diabetes medications

The purpose of diabetes medications is to help manage how your body uses sugar (glucose). Not all lead to weight changes — some may even help you lose weight.

However, one medication class that can lead to weight gain is sulfonylureas. These include drugs like:

Changing the medication type or dosage may help reduce potential weight gain, but speak with a doctor about your treatment options to ensure the best health outcome.


In some chronic conditions, particularly where inflammation plays a role, as with rheumatoid arthritis or multiple sclerosis, healthcare professionals prescribe corticosteroids to reduce inflammation and suppress your body’s immune response.

However, they can also lead to water retention and weight gain.

For example, prednisone (Prelone) can affect both sodium and potassium, with your body responding by retaining water. If you use steroids long term, you may end up feeling bloated from an excess of water.

Speak with a healthcare professional about how best to manage water retention and weight management if you’re taking corticosteroids. Getting at least 2.5 hours of exercise each week and eating a diet low in processed foods and sodium is a good place to start.


These medications block the effects of the hormone epinephrine, also known as adrenaline, which helps lower blood pressure. Examples include atenolol (Tenormin) and propranolol (Inderal LA).

Beta-blockers slow the heart rate, and this decreased rate can leave you feeling tired and can prevent your heart rate from rising during exercise.

Discussing your options with a healthcare professional can ensure your medications interrupt your daily activities as little as possible.

Birth control

The most common form of birth control is the combined hormonal pill. These contain two hormones — progestin and estrogen — and may cause weight gain in some people due to:

  • water retention
  • increased appetite
  • increased muscle tissue
  • increased body fat

However, research shows that many people taking combined birth control report both weight loss and weight gain, which is why medication package inserts advise of both as possible side effects. Overall, more research is necessary to confirm whether weight gain is a significant side effect of these medications.

Examples of combined hormonal birth control pills include:

How to manage medication-related weight gain

A doctor or pharmacist can go through potential side effects before starting a new medication. If weight gain is a risk, ask them about the advantages and disadvantages and what you can do to benefit most from your medication.

If you’re already taking medication and having difficulty managing your weight, you could try:

  • Asking about similar medications that don’t lead to weight gain: Depending on your condition, this may be your best option, and it could help to make a switch if possible.
  • Consulting with your pharmacist: Pharmacists are usually able to advise on side effects like weight gain. They can help you track them and find a solution.
  • Making manageable lifestyle changes: Making meaningful lifestyle adjustments like eating a healthy diet and avoiding sugary drinks and highly processed foods can benefit your overall health. If you’re able, adding regular exercise can also help manage your weight.

If you are frustrated with weight gain from medications, it’s important not to stop taking your prescribed drug. A doctor or healthcare professional will typically consider the risks and benefits to your overall health, and gaining a few extra pounds may not override the benefits of the medications.


Some medications, like antidepressants, beta-blockers, and sulfonylureas, can lead to weight gain, but there are ways you can help manage this, like making lifestyle changes.

Weight gain may be due to the medications affecting your appetite, how your body holds water, or how much energy you have to exercise.

You can speak with the prescribing doctor or a pharmacist and ask them any questions about how best to manage weight gain through medications.

Download the free Optum Perks Discount Card to save up to 80% on some prescription medications.

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