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Zonisamide for Weight Loss: What You Need to Know

<p>Zonisamide for Weight Loss: What You Need to Know</p>
Dr. Constance Odom, MD Picture of Dr. Constance Odom, MD

Medically reviewed by

Written by our editorial team.

Last Edited 6 min read

If you are like many people who are looking to lose weight, chances are you’ve heard about prescription drugs that have the side effect of weight loss. These drugs are growing quickly in popularity, with medications like Ozempic and Wegovy taking center stage.

However, another prescription drug is being used for weight loss, but it is not intended for that purpose alone. Zonisamide, a medication designed to treat partial-onset seizures and epilepsy, works on the central nervous system (CNS) and reduces the number and severity of seizures. This medication is available by prescription only and is available in two forms of doses—a capsule and liquid suspension.

This medication can also be used for weight loss. 

If you are looking into this medication for weight loss, there are a few things you should know. According to the American Psychiatric Association, Zonisamide is somewhat effective in facilitating weight loss, but its success comes with a price. Zonisamide is associated with a number of adverse events, including life-threatening situations. A one-year study carried out by the Duke University Medical Center included 134 obese women and 91 obese men. 

None of the study’s participants had diabetes mellitus, but all participants were given two doses of a placebo, 200 milligrams of Zonisamide, or 400 milligrams of Zonisamide. Researchers found that those taking a higher dose of this medication had more adverse effects than those who took a placebo.  

Adverse events and side effects of this medication include the following:

  • Decreased vision

  • Blindness

  • Eye pain

  • Fast, racing, or irregular heartbeat

  • Sadness and despair

  • Loss of appetite

In April of 2022, Glenmark, the drug’s manufacturer, was set to pull the drug from the market. Glenmark is an Indian multinational pharmaceutical company. It announced that it would recall “several lots of” the medication, due to the fact that there were gaps in the company’s microbiology quality control system. This was the result of a lack of data.

Despite these problems, this drug has yielded many benefits for those who want to lose weight, experts say. Studies have found that individuals who take 400 milligrams of this drug daily over the course of one year lost an estimated 7.5 pounds more than individuals who attempted to lose weight through an active lifestyle and a healthy diet alone. However, those who were prescribed this drug experienced more side effects than participants who did not take the medication.

However, the question remains. How does Zonisamide cause weight loss? According to experts, Zonisamide facilitates weight loss by increasing monoamines, a neurotransmitter that contains one amino group. Examples of monoamine transmitters include dopamine, serotonin, and norepinephrine. 

 When monoamine is increased in the body, your appetite is suppressed. Experts believe that this drug stimulates pro-opiomelanocortin receptors in the hypothalamus. The hypothalamus is the part of the brain that’s responsible for stabilizing your body and its functions. The hypothalamus regulates hormones and carries out a number of other functions. 

Zonisamide blocks certain pores on nerve cell surfaces. These pores are called calcium channels and sodium channels. These are used to transfer electrical impulses. These impulses take place between nerve cells, according to the European Medicines Agency.   

Contrary to what many people think, Zonisamide does not act on enzymes in the liver. Instead, it is eliminated primarily through urine. It is also eliminated minimally through feces. Although it was designed primarily to treat epilepsy, Zonisamide was found to cause weight loss in adults with obesity. While this drug has been found effective in helping people lose weight, you should also be aware of other potential side effects. 

To lose weight with this medication, it should be combined with a healthy diet and exercise. Other side effects of this drug include nausea, vomiting, depression, and anxiety. Despite the fact that this drug is approved only to treat seizures, doctors are prescribing it off-label for other purposes, such as weight loss. Experts believe that this drug causes weight loss by affecting the neurotransmitters, serotonin and dopamine. 

Studies have found Zonisamide to be very effective in helping women lose weight. When you take Zonisamide and decrease your caloric intake by 500 calories, women may see an average weight loss of 11 pounds. This weight loss is significantly higher than the amount of weight lost by women eating a healthy diet and increasing their physical activity. 

While scientists are certain that Zonisamide facilitates weight loss, more research is needed on the drug’s long-term side effects. Individuals who take this medication along with diet and exercise may lose 16 pounds, on average, according to many studies. However, it is important to talk with your doctor before you get a prescription for this medication. 

As a rule, those who take a daily dosage of 400 milligrams lose the most weight. Those who are serious about losing weight with Zonisamide should also be aware that Zonisamide comes with dietary restrictions. 

Because alcohol increases side effects on the nervous system and causes dizziness, it is important to eliminate or reduce your consumption of alcohol while taking this medication. Alcohol can also lead to sleepiness and trouble concentrating. Doctors caution you not to take more than your prescribed dosage of this medication, as doing so can impair your alertness. This can lead to problems when driving.

Zonisamide has been considered a possible treatment for Parkinson’s Disease, according to PubMed. Experts also believe it to be effective in reducing the symptoms of Parkinson’s Disease in patients with epilepsy.

While this drug has many benefits, it is important to know about possible drug interactions. Be aware that Zonisamide interacts with a number of other drugs. These include drugs such as Benadryl, fish oil, and Keppra. Keppra is another antiseizure medication that is often combined with other epilepsy medications. 

Reports have said that Zonisamide is associated with a metabolic disorder that increases your risk of bone disease and kidney stones. Also known by its brand name, Zonegram, Zonisamide is made by a Japanese pharmaceutical company called Eisai Co. This drug has the potential to cause metabolic acidosis, which is a buildup of acid in the body. Metabolic acidosis is often the result of kidney disease or kidney failure.

Another negative side effect of this drug is increased seizure frequency and more severe seizures.

Experts recommend that those taking Zonisamide be tested for metabolic acidosis. Blood work should measure a chemical called serum bicarbonate. You should contact your doctor immediately if you experience side effects, such as a fast heart rate, shortness of breath, fever, or chills. Other dangerous side effects of this medication are blood in your urine and severe pain in your lower back. 

You should not take this medication if you are allergic to it or other sulfa drugs, such as Septra. A reaction to a sulfa drug can lead to death. Vision loss from this drug can be permanent. Discuss any eye pain or eye redness with your doctor. Vision changes should be reported as soon as you discover them.

This drug has led to suicidal thoughts in some people. Because of this, it is important to stay attuned to any changes in your mood or behavior. You should discuss any new or worsening symptoms with your doctor. Symptoms may include irritability, agitation, hostility, or restlessness. 

In recent studies, 57 percent of participants in studies lost five percent of their body weight. Those taking a placebo typically saw no reduction in weight. This drug is effective when used the right way. However, you also need to ask yourself if you are willing to risk developing other medical conditions. Because blindness is a potential and possible side effect, it may be wise to consider other options. 

According to the Mayo Clinic, Zonisamide can cause hyperammonemia, a condition where there is too much ammonia in the blood. This can cause brain damage, and in some cases, can have a fatal outcome. 

If you are considering taking Zonisamide for weight loss, you should discuss it with your doctor first. Tell him or her about any allergies you may have. Be sure to tell your doctor about all your allergies, including allergies to medication and food. Experts have not yet determined whether this drug is safe for children under 16 years of age. The safety of this medication has not been validated. 

Geriatric patients should be aware of other factors. Many people in later life suffer with a number of conditions, so the side effects of this medication may not be as much of a hindrance for the older population. It is still believed to be helpful in facilitating weight loss. 

Zonisamide should not be used with Methotrexate, Orlistat, or Calcifediol. Taking any of these medications with Zonisamide can lead to an increased risk of some side effects. However, using one of these drugs with Zonisamide may be ideal for you. It all depends on your situation. If you are taking one of these medications with Zonisamide, your doctor may explore other drug options that are compatible with Zonisamide.



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This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your physician about the risks and benefits of any treatment. Nu Image Medical may not offer the medications or services mentioned in this article.