Phentermine and Qsymia after Gastric Sleeve or Bypass

Steph Wagner MS, RDN

August 14, 2024

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You’ve probably heard about Phentermine, or you may have taken it before you had a Gastric Sleeve or Bypass. Qsymia is a drug that uses Phentermine and adds the drug Topiramate. Both of these medications are more affordable options compared to the newer Wegovy or Zepbound GLP1s.

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While the newer ones are more effective, there is no one-size-fits-all approach to Obesity care. Patients may look to other FDA-approved medications for weight management for cost reasons or if the side effects of other medications are too strong or the results aren’t there.

Find out about all 7 FDA approved medications for Obesity here!

There is a lot of information to overwhelm yourself with regarding medication management. Instead, stick with me and I will tell you what you need to know about medications like Phentermine and Qsymia, even after bariatric surgery.

So why would someone go back to Phentermine (or Qsymia) after Gastric Sleeve or Bypass? And why instead of the newer medications? Let’s get to it!

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What is Phentermine?

Phentermine is the oldest of the FDA-approved medications and also the least expensive. There are several brand names for prescription phentermine including Adipex and Lomaira. It is an oral medication taken once daily. The dose often starts at 15 mg per day and can be titrated up to 37.5 mg.

Phentermine’s primary benefit is appetite suppression. Originally the FDA approved the medication for a short window of time but after more research and use of the drug, it’s been determined safe for long-term use.

Keep scrolling and I’ll share more about Qysemia which combines another drug with Phentermine and increases the average weight loss by up to 7% more.

When or why use Phentermine after gastric sleeve or bypass?

Bariatric surgery continues to be the most effective treatment for the disease of obesity. It’s super exciting that we also have medication options to add to the toolbox because weight reoccurrence after the first year post-op can be a common part of the journey. What we don’t know is how much. Everyone is different.

A medication like Phentermine or Qsymia after bariatric surgery is safe and effective and can help continue to manage Obesity and Obesity-related diseases in the long run.

While the newer medications have made a big splash, one of the benefits of all the attention to medications is highlighting other options that have been around for a while like Phentermine, Qsymia, Contrave and Orlistat.

Post-op patients also have the benefit of already undertaking major lifestyle changes so the learning curve to introduce a medication is likely not as steep!

FDA approved medications for obesity ingredients and brand names

Side effects and contraindications of taking Phentermine after bariatric surgery?

If you are familiar with Phentermine, you likely know that it is a stimulant. Some patients may dislike the feeling of increased heart rate or struggle to sleep well even when the medication is taken in the morning.

The potential side effects therefore include restlessness, insomnia, headache, dry mouth, tachycardia (rapid heart rate), or blood pressure elevation.

Those who should not take Phentermine include those with active coronary artery disease, uncontrolled blood pressure, hyperthyroidism, or agitated states.

What is Qsymia?

Qsymia is a drug that combines Phentermine and Topiramate. It’s only slightly more expensive than Phentermine alone and much more affordable than GLP1s if they are not covered by insurance. Some providers may prescribe the drugs individually and layer the medications to increase affordability.

This is a great reminder of the benefit of working with an Obesity specialized provider. They are familiar with the medications, the costs, and the layering of medications to manage side effects. You can use the Find a Provider feature on Obesitymedicine.org for practitioners in your area.

Qsymia is an oral medication taken three times a day. I’ll cover potential side effects and contraindications below.

When or why use Qsymia after Gastric Sleeve or Bypass?

This will sound like a broken record if you’ve read my other posts about medications after surgery but here we go again!

Bariatric surgery continues to be the most effective tool in the treatment of Obesity. Medications are another wonderful tool to add the the toolbox and can enhance or prolonge the benefit of surgical treatment. Weight reoccurrence is a common part of the journey and that does not mean failure of the patient. It means the reoccurrence of a metabolic disease.

It’s wonderful news that we have a growing list of treatment options!

Qsymia might be a good option not only for affordability but also if someone is struggling with hunger control despite staying hydrated, focusing on protein, getting good sleep, and working with a Dietitian to uncover any other causes of hunger.

If someone is struggling more with cravings than hunger, they may want to pursue Contrave as an option to help with cravings.

Side effects and contraindications of taking Qsymia after Gastric Sleeve or Bypass?

Because Qsymia has Phentermine as an active ingredient, the same side effects and contraindications are true for this drug. Potential side effects include restlessness, insomnia, headache, dry mouth, blurred vision, tachycardia, mental clouding, or mood changes.

The cautions or contraindications for Qsymia include glaucoma, hypothyroidism, kidney stones, and metabolic acidosis.

Estimated cost for Phentermine and Qsymia

Many people will qualify for Phentermine or Qsymia using the metrics of BMI. The medication is for anyone with a BMI over 30 (or BMI over 27 with a weight-related co-morbidity) or those experiencing a weight plateau or weight reoccurrence after bariatric surgery.

Phentermine is by far the least expensive medication approved by the FDA for Obesity treatment. Prices can be as low as $6 a month.

Qsymia as a brand name might cost around $130 a month. Some providers will prescribe Phentermine and Topiramate separately if the price is lower. Topiramate is more expensive than Phentermine in general but this approach might save money.

Where to go for prescription and monitoring?

When it comes to healthcare, you do want to make sure you are working with qualified experts. There are online programs that will offer medications virtually which might be an option if you don’t have another, but I do believe it’s worth looking for an Obesity specialist in your area for long term Obesity care.

I recommend contacting your surgical team to ask if they offer medical management of obesity. If you don’t have access to your team, visit obesitymedicine.org and use the Find a Provider option. These are obesity medicine experts who know medications and the disease very well.

What happens when you stop taking medication?

I get this question all the time. I’ve even been asked by other dietitians what happens when someone stops taking the medication. How do we teach them to maintain the weight loss?

The short answer is that we don’t. This is a medication treating a chronic disease. It’s not about teaching someone to keep weight off. While some patients may be able to maintain weight when the medicine is titrated down, the vast majority will experience weight relapse when the medicine isn’t present.

If for any reason you need to discontinue Phentermine or Qsymia, work with your providers to make the smoothest transition possible. Good news, your Gastric Sleeve or Bypass will continue to serve you with portion control!

That’s a hard pill to swallow (or injection to take). The medications are indicated for long-term use and that means cost and management are long-term.

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2 thoughts on “Phentermine and Qsymia after Gastric Sleeve or Bypass”

  1. I had amazing success with gastric bypass and lost 100% of my excess weight. Over time hunger came back in a big way and I was afraid of gaining even though I was eating on plan. When I had the follow up I had with medical obesity they decided to put me on Lomaira. They have just upped my dose. The nice thing about the Lomaira is that the pill is easily broken in two so you can get dose as low as 4 mg. I wasn’t eligible for other meds since my issue was hunger not weight gain.

  2. Thank you for sharing your experience! Wow tremendous success for 100% excess weight loss (less than 5% of patients hit 95%) and I love that your care team is identify what tools to you use to manage your symptoms and maintain your weight loss.

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