Contrave and Effexor Drug Interactions: What to Know

Contrave is a prescription weight loss medication that combines bupropion hydrochloride and naltrexone hydrochloride to help certain adults lose weight when used alongside a reduced calorie diet and increased physical activity. Effexor, a selective serotonin reuptake inhibitor, is commonly prescribed to treat depression and anxiety disorders. While both medications have their uses, taking Contrave alongside Effexor can lead to increased risk of side effects due to drug interactions between their active ingredients.

However, those taking these drugs together need to be aware of Contrave and Effexor drug interactions.

In this article, we’ll explore how these drugs interact, other precautions to take, and when to tell your doctor about any concerning symptoms.

Key Takeaways

• Taking Contrave with Effexor can increase the risk of high blood pressure, seizures, and central nervous system (CNS) toxicity due to overlapping effects on neurotransmitters.
• Those with a history of bipolar disorder, seizure disorder, or brain tumor should discuss their health history with a healthcare professional before starting either medication.
• Certain side effects, such as chest pain, pale stools, and dark urine, may indicate severe reactions requiring medical attention.

How Contrave Works and Its Risks

Contrave treatment combines two active drugs—bupropion hydrochloride and naltrexone hydrochloride—to help compatible adults lose weight through a reduced-calorie diet and increased physical activity. These extended release tablets work on the brain’s reward and appetite regulation centers, reducing cravings and making it easier to adhere to a weight loss plan.

However, the effects of both bupropion and naltrexone hydrochloride on the central nervous system come with increased risk of side effects, particularly for those with certain preexisting conditions.

Contrave and Effexor Drug Interaction Overview

Concern	Details
Seizure Risk	Both drugs lower the seizure threshold, increasing seizure risk. Higher risk for those with seizure disorder, brain tumor, or alcohol use.
Blood Pressure	Can increase blood pressure and worsen conditions like high blood pressure, heart disease, and chest pain.
CNS Toxicity	May cause agitation, confusion, tremors, and serotonin syndrome due to excessive neurotransmitter activity.
Bupropion Effects	Used in Contrave and Wellbutrin, lowers seizure threshold and may increase blood pressure.
Naltrexone Effects	Used in Contrave, reduces cravings but may cause nausea, dizziness, and low blood sugar.
Alcohol Use	Increases seizure risk and may worsen side effects. Avoid alcohol while taking these medications.
Liver Concerns	Signs of liver issues include dark urine and pale stools. Seek medical attention if these occur.
Drug Interactions	Combining Contrave and Effexor increases risks of high blood pressure, seizures, and CNS toxicity.
Diet Pills & Effexor	Many diet pills contain stimulants that can worsen heart risks when taken with Effexor.
Effexor & Bupropion	This combination can cause agitation, tremors, and seizures due to nervous system effects.

Active Ingredients in Contrave

Bupropion hydrochloride

• Originally developed as an antidepressant, bupropion is the main ingredient in Wellbutrin XL and Wellbutrin SR and is also used to help people quit smoking under the brand Zyban.
• Bupropion increases levels of dopamine and norepinephrine, two neurotransmitters involved in motivation, focus, and energy regulation.
• While this mechanism can help suppress appetite in certain individuals, it also lowers the seizure threshold, meaning seizures are more likely in individuals with certain risk factors, including a history of seizure disorder, brain tumor, or eating disorders.
• The medication can also lead to high blood pressure and should be used with caution in individuals at risk for cardiovascular issues.

Naltrexone hydrochloride

• Originally used to treat opioid and alcohol dependence, naltrexone hydrochloride reduces cravings and decreases the brain’s response to rewarding stimuli, making it easier for individuals to resist food cravings.
• Naltrexone affects the opioid receptors in the brain, altering the way the brain perceives pleasure and addiction-related behaviors.
• It can cause nausea, dizziness, and low blood sugar, especially in individuals with diabetes or those who are taking Contrave while following a reduced calorie diet.
• People who have recently consumed alcohol or are dependent on opioids should not take Contrave due to the risk of withdrawal symptoms and severe drug interactions.

Effects on the Central Nervous System

Since both bupropion and naltrexone impact the central nervous system, taking Contrave can lead to a variety of neurological side effects. Ritalin also affects the CNS, influencing dopamine and norepinephrine levels, which can further amplify these effects. Learn more about how Contrave and Ritalin drug interactions impact the brain and body.

Neurological side effects may include:

• Dizziness and confusion – Due to effects on norepinephrine and dopamine.
• Tremors and muscle twitching – Caused by the lower seizure threshold.
• Increased risk of CNS toxicity – When combined with certain medications, including Effexor and monoamine oxidase inhibitors (MAOIs).

Risk of Seizures and Blood Pressure Concerns

Due to the impact of both bupropion and naltrexone on neurotransmitters and blood circulation, taking Contrave can increase blood pressure and put individuals at higher risk of developing cardiovascular issues.

Those with a history of high blood pressure, chest pain, or cardiovascular disease should speak with a healthcare professional before starting Contrave.

Additionally, individuals who have recently drunk alcohol or use other drugs affecting blood pressure should be cautious when taking Contrave to avoid dangerous spikes in blood pressure.

Boxed Warning Alerts Doctors

A boxed warning alerts doctors about the potential for suicidal thoughts in those taking bupropion hydrochloride, especially in younger individuals and those with a history of bipolar disorder or depression.

• Patients should be monitored closely for mood changes, especially when starting Contrave treatment or after a dose adjustment.
• If symptoms such as suicidal thoughts, agitation, or unusual behavior changes occur, immediate medical attention is required.
• Those with a personal or family history of bipolar disorder should discuss their health history with their doctor before starting Contrave.

Additional Considerations for Safety

• Avoiding alcohol is strongly recommended when taking Contrave, as reduced alcohol tolerance and increased risk of seizures can occur.
• If signs of serious liver issues, such as dark urine or pale stools, develop, individuals should seek medical attention immediately.
• Patients should follow a regular dosing schedule and avoid taking Contrave with high-fat meals, as this can increase the absorption of bupropion and lead to side effects.

Understanding the risks associated with Contrave treatment is essential for safe and effective weight management.

Before starting Contrave, always tell your doctor about any other medications, preexisting conditions, and potential risk factors

Effexor’s Mechanism and Concerns

Effexor, or venlafaxine, is a selective serotonin reuptake inhibitor used to treat depression and anxiety. It increases serotonin and norepinephrine levels in the brain, which can lead to high blood pressure and increased risk of CNS toxicity when combined with other drugs like Contrave.

Effexor is also linked to low blood sugar, which can be worsened by weight loss medications. If you are taking Contrave, monitoring for symptoms of low blood sugar, such as dizziness and confusion, is essential.

Why Taking Contrave with Effexor Can Be Risky

Combining Contrave treatment with Effexor presents significant health risks due to their effects on the central nervous system, blood pressure, and seizure threshold. While both medications are used to treat different conditions—Contrave for weight loss and Effexor to treat depression—their overlapping mechanisms can result in serious drug interactions and side effects.

Patients considering this combination should carefully evaluate their health history and discuss possible interactions with a healthcare professional to minimize risks.

1. Increased Risk of Seizures

Both bupropion hydrochloride (found in Contrave) and Effexor influence neurotransmitter activity in the brain. This can increase the risk of seizures by lowering the seizure threshold, making seizures more likely to occur, particularly in individuals with:

• Seizure disorder – Those with a diagnosed history of seizures should avoid this combination altogether.
• Brain tumor – Tumors affecting the central nervous system can amplify the risk of uncontrolled neural activity.
• Bipolar disorder – Mood stabilizing medications often prescribed for bipolar disorder can interact negatively with Contrave and Effexor.
• Alcohol problems – Those who drink alcohol frequently while taking these medications increase seizure risk.

Additionally, the risk is higher for individuals who have missed doses, suddenly stopped taking their medication, or who take Contrave with other drugs that further lower the seizure threshold.

Dr. Matthew Olesiak, Chief Medical Director at SANE MD, warns, “Patients considering taking Contrave with Effexor should discuss their seizure risk with their doctor, as both medications can significantly lower the seizure threshold.”

What You Can Do:

• Tell your doctor if you have any history of seizures or neurological disorders before starting Contrave treatment.
• Avoid drinking alcohol, which can contribute to low blood sugar and increase the risk of seizures.
• Follow a regular dosing schedule and do not suddenly stop taking either medication without medical supervision.

2. Blood Pressure and Cardiovascular Risks

Taking Contrave alongside Effexor can significantly increase blood pressure, raising concerns for individuals with existing cardiovascular conditions.

Contrave treatment already carries a risk of high blood pressure due to both bupropion hydrochloride and naltrexone hydrochloride affecting blood circulation. Effexor further compounds this issue by increasing norepinephrine levels, which can constrict blood vessels and lead to chest pain or even a hypertensive crisis.

Those at risk include individuals with:

• Heart disease – Increased cardiovascular strain can lead to complications.
• High blood pressure – Both drugs can increase blood pressure beyond safe levels.
• Chest pain – May indicate underlying cardiovascular stress requiring medical attention.

Signs of a Severe Cardiovascular Reaction:

• Persistent headaches that do not subside
• Eye pain or blurred vision, indicating potential pressure buildup
• Chest pain or discomfort, especially with exertion

If you experience any of these symptoms, seek medical attention immediately.

What You Can Do:

• Monitor blood pressure regularly while taking Contrave and discuss concerns with your healthcare professional.
• Avoid high-fat meals, which can alter Contrave’s absorption and exacerbate side effects.
• If you have pre-existing heart conditions, your doctor may recommend a dose adjustment or an alternative medication.

3. Central Nervous System Toxicity

The concomitant use of Contrave and Effexor can result in CNS toxicity, a serious condition that occurs when excessive neurotransmitter activity overstimulates the brain.

Since both drugs affect dopamine, norepinephrine, and serotonin, taking Contrave with Effexor may lead to dangerously high levels of these neurotransmitters. This can cause symptoms ranging from mild neurological disturbances to life-threatening conditions such as serotonin syndrome or severe agitation.

Signs of CNS Toxicity:

• Severe agitation – Patients may feel restless or overly anxious.
• Confusion – Trouble thinking clearly or feeling detached from reality.
• Tremors and muscle rigidity – Uncontrolled shaking or spasms.
• Skin rash – A sign of severe allergic reaction or underlying toxicity.

Dr. Olesiak advises, “Those taking Contrave should be aware of signs of central nervous system toxicity when combining it with Effexor, as early symptoms may progress rapidly.”

What You Can Do:

• Tell your doctor if you experience any signs of CNS toxicity, even if mild.
• Avoid other certain medications that may interact, such as monoamine oxidase inhibitors (MAOIs) or over-the-counter stimulants.
• If you experience life-threatening symptoms, such as extreme confusion or tremors, call a local emergency number or seek medical attention immediately.

Additional Precautions

1. Other Drug Interactions – Combining Contrave and Effexor with other drugs, such as sedatives or stimulants, can lead to different interactions that may worsen side effects.
2. Low Blood Sugar Concerns—Contrave can contribute to low blood sugar, which Effexor may further impact. Watch for signs like dizziness and confusion.
3. Avoiding Alcohol – Drinking alcohol while on these medications can increase the risk of side effects, including seizure disorder, high blood pressure, and CNS toxicity.
4. Risk of Overdose – The combination of these medications can lead to accidental overdose, especially if taken in excessive amounts or mixed with other substances.

By carefully considering these risks and telling your doctor about any other medications, starting Contrave treatment safely becomes more manageable.

Who Should Avoid This Combination?

Some individuals are at a higher risk of severe reactions when taking Contrave with Effexor. Those with the following conditions should exercise caution:

• Bipolar disorder – Both medications may trigger manic episodes.
• Seizure disorder – Due to Contrave’s effect on the seizure threshold.
• Liver disease – Symptoms like pale stools and dark urine may indicate liver stress.
• Recent use of monoamine oxidase inhibitors (MAOIs) – Can cause life-threatening interactions.

Precautions and Safety Measures

1. Tell Your Doctor About Other Medications

Always tell your doctor about any other medications or supplements you are taking, including:

• Over-the-counter medications, including NSAIDS, such as ibuprofen.
• Other drugs for depression (Zoloft, Lexapro, Cymbalta, Prozac, Wellbutrin, etc), or weight loss (Mounjaro, Phentermine, Qsymia, Ozempic,
• Certain medications like blood thinners or sedatives

2. Follow a Regular Dosing Schedule

A regular dosing schedule minimizes side effects and ensures the body adjusts safely. If a missed dose occurs, do not double up on the next dose.

3. Avoiding Alcohol and High-Fat Meals

• Avoiding alcohol reduces the risk of seizures and CNS side effects.
• High-fat meals can alter how Contrave is absorbed, increasing side effects.

4. Seek Medical Attention for Severe Side Effects

If you experience life-threatening symptoms like:

• Severe chest pain
• Dark urine or pale stools
• Uncontrollable tremors

Call a local emergency number or visit the nearest ER immediately.

FAQ: Contrave, Effexor, and Drug Interactions

When considering medications like Contrave and Effexor, it’s important to understand their potential drug interactions and health risks. Since both drugs affect the central nervous system, blood pressure, and seizure threshold, combining them may not be safe for everyone.

Below are answers to some common questions about using Contrave treatment alongside Effexor and other medications.

1. Can I take Effexor and buPROPion together?

Effexor (venlafaxine) and buPROPion hydrochloride (found in Contrave, Wellbutrin XL, and Wellbutrin SR) are sometimes prescribed together, but this combination carries risks. Both medications increase norepinephrine and dopamine levels, which can raise blood pressure and the risk of seizures by lowering the seizure threshold.

Additionally, taking them together may contribute to CNS toxicity, causing agitation, tremors, and confusion. If your doctor prescribes both, they may recommend a dose adjustment and close monitoring to reduce the chance of severe side effects.

Tell your doctor about any history of seizure disorder, bipolar disorder, or high blood pressure before starting both medications.

2. Can you take Contrave with antidepressants?

It depends on the type of antidepressant. Contrave drug interactions are common with selective serotonin reuptake inhibitors (SSRIs) or serotonin-norepinephrine reuptake inhibitors (SNRIs) like Effexor can lead to possible interactions, including CNS toxicity and an increased risk of high blood pressure and seizures. Additionally, bupropion hydrochloride, a key ingredient in Contrave, is itself an antidepressant (Wellbutrin), so adding another antidepressant could amplify effects on mood and energy levels.

Before starting Contrave treatment, tell your doctor about any other medications for depression to ensure safe use and avoid serious complications.

3. What meds cannot be taken with Effexor?

Effexor should not be combined with monoamine oxidase inhibitors (MAOIs), such as phenelzine and tranylcypromine, as this can cause life-threatening serotonin syndrome. Additionally, Effexor should not be taken with other drugs that affect serotonin levels, such as other SSRIs, SNRIs, or triptans, due to the risk of excessive serotonin buildup. Medications that increase blood pressure, such as stimulant-based weight loss drugs, should also be used with caution.

Tell your doctor if you are taking any over-the-counter cold medicines, blood thinners, or migraine medications, as these may interact differently with Effexor.

4. Can you take diet pills with venlafaxine?

Using weight loss drugs or diet pills with Effexor (venlafaxine) is generally not recommended due to their combined effect on blood pressure and the seizure threshold. Many diet pills contain stimulants, which can further increase blood pressure and cause rapid heart rate, anxiety, and insomnia. Since taking Contrave or other weight loss medications already poses cardiovascular risks, adding venlafaxine can compound these effects and lead to dangerous side effects like chest pain, tremors, or CNS toxicity.

Always consult a healthcare professional before combining any diet pills or weight loss drugs with Effexor.

5. Can Contrave be taken with venlafaxine?

Taking Contrave with Effexor (venlafaxine) is generally not advised unless a healthcare professional determines that the benefits outweigh the risks. Both medications can increase blood pressure, lower the seizure threshold, and lead to central nervous system toxicity if taken together. Individuals with bipolar disorder, high blood pressure, or a history of seizure disorder are at a higher risk of complications when using this combination.

If you are considering starting Contrave treatment while on Effexor, tell your doctor about your health history and any other drugs you are taking to ensure safe and effective treatment.

Final Thoughts

Taking Contrave with Effexor is not always safe, particularly for individuals with underlying conditions affecting the central nervous system, blood pressure, or seizure threshold. Tell your doctor about your health history before combining these medications to minimize potential risks.

Patients can make informed decisions about their Contrave treatment by understanding the different interactions, following a medication guide, and recognizing early signs of complications.