Contrave and Buspar Drug Interactions: Safe to Combine?

Combining medications can sometimes lead to unintended consequences. For individuals using Contrave for weight loss and Buspar (buspirone) for anxiety, it’s important to understand how these two drugs might interact. While both can be helpful in managing separate conditions, certain drug interactions may increase the risk of side effects, reduce effectiveness, or require monitoring by a healthcare provider.

This article takes an objective look at Contrave and Buspar drug interactions, with guidance on how to take both medications safely—if at all. We’ll cover known risks, overlapping side effects, and what to discuss with your health care professional before starting or combining these prescriptions.

Key Takeaways

• Combining Contrave and Buspar may increase the risk of side effects such as dizziness, confusion, and blood pressure changes.
• Patients with a history of seizures, mental health changes, or high blood pressure should consult a healthcare professional before combining these medications.
• Careful monitoring and potential dosage adjustments may be needed when taking Contrave and Buspar together.

What Is Contrave?

Contrave is a prescription medication approved for chronic weight management in certain adults with a BMI over 30—or over 27 with a weight-related health condition such as type 2 diabetes or high blood pressure. It combines two active ingredients: naltrexone hydrochloride and bupropion hydrochloride, each with unique effects on the brain.

• Bupropion is an antidepressant also used to help patients quit smoking and treat depression.
• Naltrexone is traditionally used to treat alcohol and opioid withdrawal.

Together, these compounds target hunger and cravings in the brain. To achieve maximum results, patients taking Contrave are encouraged to follow a reduced-calorie diet and increase physical activity.

What Is Buspar?

Buspar, the brand name for buspirone, is an anti-anxiety medication. Unlike benzodiazepines, Buspar does not cause sedation or dependency. It works by affecting serotonin and dopamine receptors in the brain, and is often used to treat generalized anxiety disorder.

Buspar is typically taken multiple times a day and may take several weeks to become effective. It’s generally well-tolerated but can cause side effects like dizziness, headaches, nausea, and restlessness.

While there’s no official contraindication that forbids taking Contrave and Buspar together, combining these medications may increase the risk of certain side effects or cause overlapping central nervous system (CNS) effects, such as:

• Dizziness
• Drowsiness
• Confusion
• Difficulty concentrating
• Increased blood pressure

Both medications influence brain chemistry. Contrave affects norepinephrine and dopamine, while Buspar acts mainly on serotonin receptors. In rare cases, this could lead to serotonin syndrome, a potentially life-threatening condition. Symptoms of serotonin syndrome include agitation, rapid heartbeat, hallucinations, and trouble breathing.

“There’s no blanket answer for whether it’s safe to take Contrave and Buspar together,” says Dr. Matthew Olesiak, Chief Medical Director at SANE MD. “It depends on the patient’s full medical history, current medications, and health goals. A health care professional must evaluate all risks and benefits before prescribing both drugs at once.”

Risk Factors to Consider

1. Seizure Risk

One of the most serious concerns when taking Contrave is its well-documented risk of seizures. This risk is primarily linked to bupropion hydrochloride, which is known to lower the seizure threshold—especially at higher doses or in individuals with specific medical conditions. People with a history of seizures, head injury, eating disorders (such as anorexia nervosa or bulimia), or those who suddenly stop drinking alcohol are at significantly higher risk. Additionally, concurrent use of over-the-counter drugs or stimulants that impact the nervous system, such as modafinil, or lower the seizure threshold, such as Tramadol and codeine, may exacerbate the issue.

Although Buspar (buspirone) is not typically associated with seizures, it does have effects on the central nervous system and may interact in unpredictable ways when combined with Contrave. The increased risk is particularly concerning in those with a neurological history or other health conditions that influence brain function. This potential interaction qualifies as one of several drug interactions that necessitate caution and close medical supervision.

Before starting Contrave treatment, patients should discuss any past head injury, loss of consciousness, or seizure activity with their health care professional. A detailed health history is critical, especially if you’re also taking other drugs that influence neurological activity. If a seizure occurs, taking Contrave should be discontinued immediately, and medical help should be sought.

2. Mental Health Changes and Suicidal Thoughts

Another major safety concern associated with Contrave is the boxed warning that alerts doctors about the risk of suicidal thoughts and mental health changes. These adverse reactions are especially likely in younger adults and during the first few months of therapy or during dosage adjustment. As bupropion is an antidepressant, it can cause behavioral shifts, particularly in those with pre-existing psychiatric diagnoses.

Buspar is often prescribed to treat depression and generalized anxiety disorder. While it tends to be well-tolerated and non-sedating, it still alters neurotransmitter activity—particularly involving serotonin. When paired with Contrave, the overlapping effects on dopamine, norepinephrine, and serotonin can increase the risk of emotional volatility or destabilize existing mental health conditions. See our guide to learn how Contrave can be used for depression.

This is particularly dangerous in patients with bipolar disorder, where certain medications can trigger manic episodes or deepen depressive ones. Additionally, if you or a family member has a history of mental health disorders, suicidal behavior, or mood swings, this should be discussed before combining these medications.

It’s essential to be aware of early warning signs, such as sudden mood changes, aggression, insomnia, impulsivity, or worsening depression. If you notice these behaviors while taking Contrave or after starting Contrave treatment, consult your healthcare provider immediately. Regular check-ins during the initial months of Contrave treatment can help prevent the escalation of symptoms.

3. Blood Pressure Changes

High blood pressure is a known side effect of Contrave and should not be taken by individuals with uncontrolled hypertension, according to the FDA-approved prescribing information.

Bupropion, by increasing norepinephrine levels, can lead to elevated blood pressure and heart rate, especially during the start of treatment phases or when combined with other drugs affecting cardiovascular function.

Buspar, while generally benign regarding cardiovascular effects, can occasionally cause fluctuations in blood pressure, particularly in those sensitive to changes in stress hormones or CNS stimulants. When used in combination with Contrave, there’s a potential increased risk of cardiovascular side effects, including rapid heartbeat, chest discomfort, and dizziness.

The concern is even greater in patients already dealing with high blood pressure or those using medications to manage it. Buspirone may also interact with certain over-the-counter medications, like decongestants, that can further elevate blood pressure or heart rate. These Contrave interactions are often overlooked but could result in serious injury if not properly managed.

“If you’re taking Contrave and notice symptoms like rapid heartbeat, chest pain, or blurred vision, talk to your doctor immediately,” adds Dr. Olesiak. “These could be signs of high blood pressure or other serious complications that require dosage adjustment or discontinuation.”

Routine monitoring of blood pressure is essential throughout the course of Contrave treatment, especially if you are also using Buspar or any other drugs that impact cardiovascular function. Keep track of symptoms and follow all guidance in the medication guide or patient package insert.

Overlapping Side Effects

Taking Contrave and Buspar at the same time may increase the risk of shared or enhanced side effects. Both medications act on the brain and nervous system, which can lead to cumulative effects in certain individuals.

Common overlapping side effects of Contrave and Buspar include:

• Nausea or vomiting
• Headaches
• Dry mouth
• Dizziness
• Sweating
• Tremors
• Insomnia or restlessness

These symptoms can vary in intensity but may be more disruptive during the early stages of taking Contrave or when initiating a new dose adjustment. For some patients, side effects like tremors, nausea, or dizziness can impair driving or routine activities, increasing the risk of accidents or falls—especially in older adults.

In a smaller subset of patients, more serious complications may develop. These include serious skin reactions, a broad category that encompasses conditions like Stevens-Johnson syndrome or toxic epidermal necrolysis—both of which are life-threatening and require emergency care.

Signs of a serious skin reaction may include:

• Skin rash or blistering
• Peeling skin
• Red or purple lesions
• Fever
• Sore throat

Additionally, signs of an allergic reaction include swelling of the face or throat, trouble breathing, severe itching, or eye pain. These symptoms require immediate cessation of medication and urgent medical care.

If you experience any of these symptoms—particularly swelling, hives, or labored breathing—call your local emergency number right away. These could indicate a medical emergency and should never be ignored. Let your provider know if you’ve ever had an allergic reaction to medications in the past, including weight loss drugs or medications used to treat alcohol or mood disorders.

Because these symptoms may also occur with systemic exposure to other medications or environmental allergens, it’s critical to have a full understanding of your health factors and any behaviors Contrave may amplify. In rare cases, even lab tests may be needed to determine the cause of your reaction or confirm drug safety.

Who Should Avoid Combining These Drugs?

The combination of Contrave and Buspar should be avoided or used with caution in people with:

• History of seizures or head injury
• Diagnosed bipolar disorder
• Uncontrolled high blood pressure
• History of eating disorders
• Recent use of monoamine oxidase inhibitors
• Current use of opioids (due to naltrexone and bupropion effects)

Additionally, people who suddenly stop drinking alcohol or who are undergoing opioid withdrawal face an increased risk of adverse reactions when taking Contrave, according to the FDA-approved prescribing information.

This risk may be compounded if Buspar is also involved.

Considerations When Taking Contrave

Contrave is provided in extended-release tablets, which should not be crushed, chewed, or split. Doing so may alter the absorption rate, leading to an increased risk of side effects. It is also important to avoid high-fat meals when taking Contrave, as they may increase the risk of seizure by raising drug levels in the blood.

Contrave is not recommended for use with certain other drugs—including over-the-counter stimulants, psychiatric medications, and weight loss supplements. Make sure your health care professional knows about all medications and supplements you take, including vitamin interactions or over-the-counter drugs.

You’ll also want to keep track of:

• Missed dose instructions (do not double up)
• Patient package insert and medication guide updates
• Changes to mental health, mood, or energy
• Whether you are pregnant or breastfeeding (breast milk transfer risk)

Blood Sugar and Caffeine Considerations

For individuals with diabetes or metabolic conditions, Contrave treatment may lower blood sugar levels. This could pose a danger if you’re also taking Buspar, which can sometimes cause dizziness or lightheadedness.

Hypoglycemia (low blood sugar) can mimic side effects of both medications, making it harder to determine the cause. Regular blood sugar monitoring and adjustment to any insulin or diabetes medications are advised.

Contrave has been shown to reduce hemoglobin A1c and fasting glucose levels in people with type 2 diabetes, according to FDA-approved clinical data, which may result in low blood sugar for some individuals.

Patients should also avoid excessive caffeine intake. Both drugs can cause insomnia, jitteriness, or restlessness—effects that may be amplified with high doses of caffeine.

How to Safely Start Treatment

Starting Contrave treatment—especially when combining it with Buspar—requires thoughtful planning and clear communication with your health care professional. Because both medications affect the central nervous system and can influence mood, blood pressure, and energy levels, it’s important to take a proactive, informed approach from the very beginning.

Before starting Contrave and Buspar together:

• Review your health history and health conditions with your provider. This includes any past or current issues such as high blood pressure, bipolar disorder, mental health diagnoses, seizures, or eating disorders. Full disclosure of your medical conditions helps your doctor determine whether it’s safe to combine these drugs or if alternative treatments are a better fit.
• Ask about potential Contrave interactions with other drugs, supplements, or foods. Both prescription and over-the-counter medications—including vitamins, herbal products, and cold medicines—may interact with naltrexone and bupropion, leading to adverse reactions or reduced effectiveness. Your provider can help identify certain drug interactions and review the medication guide or patient package insert for up-to-date safety guidance.
• Be honest about your use of alcoholic beverages and whether you plan to quit smoking. People who suddenly stop drinking alcohol or are actively detoxing from opioid withdrawal may face an increased risk of seizures or mood instability while on Contrave. Additionally, bupropion hydrochloride is sometimes used to help quit smoking, so the dosage must be carefully tailored to avoid overlapping effects or accidental duplication.
• If needed, request a dosage adjustment or consider staggering medication start times. Your doctor may recommend slowly introducing Contrave while maintaining a stable Buspar regimen, especially if you’ve recently made changes to your mental health medications. This approach allows your body to adjust gradually and reduces the likelihood of serious side effects, such as the risk of seizures, high blood pressure, or worsening mental health symptoms.

Your doctor will evaluate whether to prescribe Contrave based on a combination of factors, including your health conditions, current treatments, lifestyle, and long-term goals for chronic weight management. They may also monitor for warning signs like skin rash, low blood sugar, or trouble breathing, and recommend regular check-ins during the early phases of taking Contrave.

If you’re already on Buspar, your provider might choose to introduce Contrave using a step-up approach—starting with the lowest dose of extended-release tablets and gradually increasing it over several weeks. This titration helps limit side effects and allows your provider to intervene early if contrave-interaction symptoms appear.

In all cases, clear and ongoing communication with your healthcare provider is key. Report any new symptoms, emotional changes, or difficulties tolerating the medication. Whether your goal is to lose weight, reduce anxiety, or improve your quality of life, a safe and strategic start sets the foundation for long-term success.

Frequently Asked Questions (FAQ)

Combining medications can be confusing, especially when managing multiple health conditions like anxiety, depression, or obesity.

Below are answers to common questions related to Contrave, Buspar (buspirone), and their possible interactions. Always consult your health care professional before starting, stopping, or combining any medications.

1. What medications should not be taken with Contrave?

Contrave should not be taken with monoamine oxidase inhibitors (MAOIs), as this combination can cause dangerous spikes in blood pressure or other severe reactions. Contrave drug interactions can also occur if used with other forms of bupropion, including those used to quit smoking (like Zyban), because doing so may increase the risk of seizures. Contrave should not be taken with benzodiazepines like Xanax without medical supervision, as the combination may lead to dangerous interactions.

Additionally, opioid medications must be stopped at least 7–10 days before starting Contrave due to the naltrexone component, which can cause opioid withdrawal. Use caution with over-the-counter drugs, stimulant-containing products, and medications that may raise blood pressure or impact seizure threshold.

2. Can you take bupropion and BuSpar together?

In some cases, bupropion and Buspar may be taken together under medical supervision, but this combination requires caution. Both drugs affect brain chemistry and may increase the risk of side effects such as dizziness, confusion, anxiety, or even serotonin-related complications. People with a history of mental health conditions, seizures, or high blood pressure should be closely monitored.

Your provider may recommend dosage adjustment or staggered administration to minimize overlapping side effects.

3. What medications cannot be taken with BuSpar?

Buspar should not be combined with MAO inhibitors, as this may lead to dangerously high blood pressure. It also interacts with serotonergic drugs, increasing the risk of serotonin syndrome—a rare but serious condition. Use caution with antidepressants, antipsychotics, certain antibiotics (like linezolid), and even herbal products like St. John’s Wort.

Always disclose your full medication list, including over-the-counter and vitamin interactions, to your healthcare provider before starting treatment with Buspar.

4. Can I take Contrave if I take bupropion?

Contrave already contains bupropion hydrochloride, one of its two active ingredients. If you’re already taking bupropion for treating depression, smoking cessation, or another reason, taking Contrave at the same time could cause dangerously high bupropion levels and significantly increase the risk of seizures. Your doctor may recommend switching to Contrave or adjusting your dose, but you should never take both at the same time without professional guidance.

Be especially cautious if you have a history of head injury, eating disorders, or use alcoholic beverages regularly.

The Bottom Line

Combining Contrave and Buspar can be safe for some patients, but it carries real risks—especially if you have medical conditions like high blood pressure, a history of seizures, or current mental health challenges.

Speak with a trusted healthcare provider about the safest path forward. Do not attempt to mix or adjust medications without professional input. If you suspect an adverse reaction, reach out to your doctor or call your local emergency number immediately.

When taken carefully and with oversight, both medications can play a role in achieving better health—whether that means managing anxiety, supporting chronic weight management, or helping you lose weight safely.

SOURCES

FDA