This post was written by Afamefuna Nzekwe, PharmD, Parkview Health.
Starting a new medicine can help you feel better, control your health condition, or prevent future problems. Sometimes, though, people notice changes they did not expect—like weight gain. This can feel frustrating. The good news: there are simple steps you can take, and your care team can help.
What do we mean by “weight gain”?
Weight gain can be a few pounds over weeks to months. For some people, it is more. It may be due to changes in appetite, how your body uses energy or fluid retention (the water your body holds onto). This is not the same as sudden swelling or rapid, significant weight changes—which you should discuss with your primary care provider right away.
Medications often linked to weight gain
Not every medicine causes weight gain. But these groups are more likely to have this side effect:
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Antidepressants (selective-serotonin reuptake inhibitors/SSRIs or tricyclics)
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These can change your appetite or how your body burns calories.
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Examples: paroxetine, mirtazapine, and amitriptyline
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Antipsychotics (especially “atypical” or second-generation antipsychotics)
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These can affect hunger signals and how your body stores fat.
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Examples: olanzapine or clozapine
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Steroids (corticosteroids)
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These may increase appetite and cause your body to hold on to fluid.
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Examples: prednisone
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Diabetes medicines (insulin and some oral diabetes medications)
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As blood sugar improves, your body may store more energy.
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Oral diabetes examples: glyburide, glipizide, pioglitazone
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Beta blockers (used for blood pressure, heart conditions and anxiety)
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These can lower energy levels and reduce calorie burn
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Examples: metoprolol or atenolol
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Many people need these medicines for their health. Never stop a medicine on your own. If weight changes bother you, talk with your provider or pharmacist. There are often alternative medications or treatment options available to help manage your condition.
Why does this happen?
Several reasons can lead to weight gain with certain medicines:
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Increased appetite. Some medicines make you feel hungrier or more interested in food.
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Slower metabolism. Your body may burn fewer calories at rest.
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Fluid retention. Your body may hold water, which shows up as weight on the scale.
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Hormone changes. Medicines can shift hormones that control hunger and fat storage.
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Feeling better. As mood or blood sugar improves, people sometimes eat more regularly, which can add calories.
What can you do about it?
Small, steady changes add up. Try these tips:
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Build a balanced plate. Fill half your plate with fruits and vegetables, add lean proteins (chicken, fish, beans), and choose whole-grain carbs (brown rice, whole wheat bread).
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Watch portions and snacks. Use a smaller plate. Keep high-protein, fiber-rich snacks (nuts, yogurt, veggies) handy.
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Move most days. Aim for 30 minutes of activity, like brisk walking, biking or swimming. Strength exercises 2–3 times per week help protect muscle and boost metabolism.
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Track your trends. Weigh yourself once a week, at the same time of day. Note changes after starting or changing a medication.
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Sleep and stress. Try for 7–9 hours of sleep. Use stress-relief habits like deep breathing, stretching, or short walks.
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Talk to your care team. Ask whether a different dose, timing, or an alternate medicine could lower the risk of weight gain. Pharmacists can help review options and suggest realistic goals.
When to seek help
Reach out if you notice:
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Rapid weight gain (for example, more than 2–3 pounds in a day or 5 pounds in a week)
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New swelling in your legs, ankles or belly
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Shortness of breath, chest discomfort or feeling faint
These all may be signs of fluid buildup or another problem that needs prompt care.
The bottom line
Weight gain from medicine is common—but it can be managed. Know which medicines might cause it, make small lifestyle changes, and keep your care team in the loop. Together, you can find a plan that supports both your treatment and your long-term health.
Parkview Outpatient Pharmacies and Specialty Pharmacy provide a wide range of prescription medications and individualized support for those with chronic and complex conditions. At select locations, we offer customized medication solutions, including compounding and flavoring, making it easier for patients to take their prescribed treatments.
For more information on pharmacy services, contact or visit a location near you.
