Psychotropic-Induced Weight Gain

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Many of the psychiatric medications have side effects. Weight gain is a common one. Atypical or second-generation antipsychotics are notorious for causing weight gain. Atypical antipsychotics are effective for schizophrenia and related disorders, as well as bipolar disorder and depression, among others.

Mood stabilizers and some of the antidepressants can also cause significant gain. Antidepressants are evidence-based for both major depressive disorder and anxiety disorders; mood stabilizers are effective for bipolar disorder and sometimes for depression. So, medications in all three of these classes are commonly prescribed.

How to Prevent and Manage the Problem

To prevent gain, anyone who starts a new medication should be fully informed about the risks and benefits. For many, some weight gain is not a major concern. For these people, weight gain-promoting medications are less problematic, but still, close monitoring should be for weight gain, and other related metabolic effects should be prioritized.

Regular weight and blood tests for fasting glucose (insulin resistance, measured by high fasting blood glucose, is a precursor for diabetes) and lipid panels are important. Someone who has concerns about gaining weight, perhaps because they already have some health issues from extra body weight or simply because they have greater concern about it, might want to proceed more cautiously with initiating a medication that is known to have weight gain as a side effect, and should feel free to discuss their concerns with the prescriber.

Individuals respond variably to all psychiatric medications: Some experience no side effects, and some experience many. If, for some reason, a medication that has a risk of causing weight gain is preferred for mental health reasons, there should be careful monitoring after starting. In some cases, much of the weight gain can occur in the first month of treatment, so ideally, the patient and prescriber should meet within weeks after medication initiation to discuss the next steps. Fasting blood glucose (for insulin resistance), fasting lipid panel (for hypertriglyceridemia), and body weight should be checked regularly.

If weight gain occurs and is deemed problematic (7 percent of body weight gain on medication is considered clinically significant), the patient and prescriber can discuss the next steps. Often, reducing the dose or switching to a new antidepressant, antipsychotic, or mood stabilizer is the best course of action.

Other times, the patient and prescriber decide that staying on the medication at the current dose is best. What then? Sometimes, nutritional consultation and changes in one's diet or physical activity habits can make a big difference. Simple interventions, like cutting out sugary drinks or adding a 20-minute walk every day to the calendar, can curb the gain and provide other mental health and physical health benefits. Getting a good night's sleep is essential for weight gain prevention and weight loss promotion.

Medications Causing Weight Gain and Those Less Risky

Here are some medications to know about in each of the three classes:

• Antidepressants that have the highest risk of causing weight gain are paroxetine, mirtazapine, imipramine, desipramine, and amitryptiline.
• Antidepressants have the lowest risk of weight gain: fluoxetine and bupropion.
• Atypical antipsychotics that have the highest risk of causing weight gain are clozapine, olanzapine, and quetiapine.
• Atypical antipsychotics that have the lowest risk of weight gain: abilify, ziprasidone, lurasidone, brexiprazole.
• Mood stabilizers that have the highest risk of causing weight gain are valproate and lithium.
• Mood stabilizers with the lowest weight gain risk are topiramate, oxcarbazepine, carbamazepine, and lamotrigine.

Medication Options for Psychotropic-Induced Weight Gain

In some cases, people choose to take add-on medications. Early weight gain predicts ongoing significant gain. In one study, more than 5 percent body weight gain in the first month on a psychotropic predicted more than 15 percent after three months and more than 20 percent gain after 12 months. Therefore, medication treatment for weight gain prevention and management should be considered seriously in patients with overweight and obesity, plus a more than 5 percent body weight increase during the first month of treatment.

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Does Antipsychotic Medication Work?

Pharmacological management of weight gain from psychotropics differs slightly from general guidelines for the management of obesity. Medications that are commonly recommended for antipsychotic-induced weight gain or metabolic syndrome include glucagon-like peptide one receptor agonists, metformin, aripiprazole, and topiramate. However, some say the supporting evidence for using any of these medications is still of low quality.

Most experts suggest that metformin should be tried first for the prevention and management of psychotropic-induced weight gain, which also benefits patients by reducing insulin resistance. In a recent Cochrane review, metformin showed the most evidence for preventing weight gain in patients with schizophrenia or schizophrenia-like illnesses. In contrast, the other agents examined—nizatidine, famotidine, ranitidine, and monoamine modulators such as reboxetine and fluoxetine—were slightly effective, and topiramate was not effective, but all evidence was of low certainty.

Two atypical antipsychotic medications that are notorious for causing weight gain—clozapine and olanzapine—can be augmented with metformin, aripiprazole, topiramate, or a GLP-1 receptor agonist, keeping in mind potential side effect burdens of the individual medications. However, an additional option for olanzapine is combination treatment using add-on samidorphan.

If, for whatever reason, these medications aren't effective or cause side effects, or for other reasons aren't a good fit for the patient, standard pharmacological interventions for obesity could also be considered—still, the possible impacts of individual medications on mental health need to be thought through. For example, someone with an anxiety disorder might be made worse with topiramate-phentermine, as phentermine has stimulant effects.

Conclusion

Help is out there, and there are lots of options. Starting a medication that has a risk of weight gain is fine, even if you are at higher risk, like if you have extra body weight already and health problems related to it. The key is to stay close to your prescriber and monitor for side effects closely so you can do what is best for your mental and physical health.