Alprazolam (Xanax) has several dangerous interactions with other drugs, alcohol, and even some supplements. The most serious involve anything else that slows your breathing or central nervous system, including opioids and alcohol, which can cause fatal respiratory depression when combined with alprazolam. Beyond those high-risk combinations, certain medications are fully contraindicated because they block your body’s ability to break down the drug, causing it to build up to dangerous levels.
Opioids: The Highest-Risk Combination
Combining alprazolam with any opioid pain reliever is one of the most dangerous drug interactions that exists. Both substances slow breathing independently. Together, they can suppress your respiratory drive enough to cause death. The FDA requires a boxed warning (the strongest safety alert available) on all benzodiazepines, including alprazolam, specifically because of the risk when combined with opioids.
This applies to prescription painkillers like oxycodone, hydrocodone, and morphine, as well as illicit opioids like heroin and fentanyl. It also applies to medications used to treat opioid addiction, though in that case the benefits of treatment sometimes outweigh the risks under careful medical supervision.
Alcohol
Alcohol and alprazolam both depress the central nervous system, and their effects don’t just stack, they multiply. Even moderate drinking while taking alprazolam can cause extreme sedation, dangerously slowed breathing, loss of consciousness, and death. There is no safe amount of alcohol to drink while on this medication.
Antifungal Medications That Are Fully Contraindicated
Your liver breaks down alprazolam using a specific enzyme system called CYP3A4. Some drugs block this enzyme so completely that alprazolam accumulates in your bloodstream to unsafe levels. Two antifungal medications, ketoconazole and itraconazole, are fully contraindicated with alprazolam. The FDA labeling for Xanax explicitly states they should never be taken together because they severely impair the body’s ability to clear the drug.
Other Medications That Slow Alprazolam Breakdown
Beyond the two contraindicated antifungals, a broader group of medications partially block the same liver enzyme and can significantly raise alprazolam levels in your blood. The antidepressant nefazodone, for example, doubles the concentration of alprazolam in clinical studies. Other CYP3A4 inhibitors include certain antibiotics (particularly macrolide antibiotics like erythromycin and clarithromycin), some heart rhythm medications, calcium channel blockers, and several HIV medications.
These combinations aren’t always completely off-limits, but they typically require a lower alprazolam dose. If you’re prescribed a new medication while taking alprazolam, your pharmacist should flag the interaction, but it’s worth asking directly.
Antihistamines and Muscle Relaxants
First-generation antihistamines like diphenhydramine (Benadryl) cause drowsiness on their own. Paired with alprazolam, the sedative effects increase significantly. You may experience impaired judgment, extreme drowsiness, slowed reaction times, and depressed breathing. This is especially risky for older adults, who are more sensitive to both drugs. The same caution applies to muscle relaxants, which also depress the central nervous system.
This is easy to overlook because antihistamines are available over the counter and many people don’t think of them as “real” medications. If you take alprazolam, check the active ingredients in any allergy, cold, or sleep aid products before using them.
St. John’s Wort
St. John’s Wort, a popular herbal supplement for mood support, creates the opposite problem from CYP3A4 inhibitors. It speeds up alprazolam metabolism, which means the drug gets cleared from your body faster than expected. The result, according to the Mayo Clinic, is that alprazolam may not work as well for anxiety. This could leave you under-treated or tempted to take more than prescribed, both of which are problematic with a medication that carries dependence risk.
Respiratory Conditions That Increase Risk
Alprazolam isn’t just dangerous with other drugs. Certain health conditions make the medication itself riskier. If you have COPD or sleep apnea, alprazolam can worsen your breathing problems, particularly at night. The American Thoracic Society and European Respiratory Society guidelines recommend that people with COPD avoid benzodiazepines altogether because of respiratory side effects. Benzodiazepines have been shown to reduce breathing ability and lower oxygen levels during sleep, which is especially dangerous for someone whose lungs are already compromised.
Narrow-Angle Glaucoma
Alprazolam can dilate the pupil, which poses a specific risk for people with untreated narrow-angle glaucoma. A dilated pupil can block the drainage of fluid inside the eye, causing a sudden spike in eye pressure that damages the optic nerve. If you’ve been diagnosed with narrow-angle glaucoma that hasn’t been treated with a procedure to improve drainage, alprazolam is generally considered contraindicated.
What About Grapefruit Juice?
Grapefruit juice is a well-known CYP3A4 inhibitor that raises blood levels of many medications. You might expect it to interact with alprazolam too, but a review in Mayo Clinic Proceedings found no published evidence of a clinically significant interaction between grapefruit juice and alprazolam. While it’s reasonable to be cautious, this particular combination doesn’t appear to cause the same problems it does with other drugs in the same enzyme pathway.
Keeping Track of Interactions
The common thread across most alprazolam interactions is simple: anything that either slows your central nervous system or prevents your liver from clearing the drug can push alprazolam’s effects into dangerous territory. That includes prescription medications, over-the-counter products, herbal supplements, and alcohol. Whenever you start or stop any medication or supplement, let your prescriber and pharmacist know you take alprazolam so they can check for interactions you might not catch on your own.