- question: "What medications should I avoid while receiving ketamine therapy?

Several medication classes may interact with ketamine in clinically meaningful ways. Monoamine oxidase inhibitors (MAOIs) such as phenelzine and tranylcypromine should be avoided due to the risk of severe hypertension and serotonergic complications. CNS depressants including alcohol, high-dose opioids, and sedative-hypnotics can potentiate ketamine's sedating effects and respiratory depression risk. Some providers recommend avoiding or reducing benzodiazepines and lamotrigine around treatment sessions, as these may blunt the antidepressant response. Sympathomimetic drugs and stimulants may exacerbate ketamine's cardiovascular effects. Always provide your ketamine provider with a complete medication list, including herbal supplements and over-the-counter products, before beginning treatment. For a detailed clinical overview, see [ketamine drug interactions](/clinical/ketamine-drug-interactions/).

Can I continue taking my SSRI or SNRI during ketamine therapy?

Yes, most SSRIs and SNRIs can be safely continued during ketamine therapy. In fact, many clinical trials that established ketamine's efficacy allowed participants to remain on their existing antidepressant medications. Research has not shown significant adverse interactions between ketamine and common SSRIs such as sertraline, fluoxetine, or escitalopram, nor with SNRIs such as venlafaxine or duloxetine. Some preliminary evidence suggests that concurrent antidepressant use may even help prolong ketamine's therapeutic effects. Your provider will review your specific medications and doses. It is important not to discontinue any psychiatric medication abruptly without medical guidance, as this can cause withdrawal symptoms and symptom relapse.

Do benzodiazepines affect ketamine treatment?

There is growing evidence that benzodiazepines may reduce the antidepressant efficacy of ketamine. A study by Frye and colleagues published in the Journal of Clinical Psychopharmacology found that patients taking benzodiazepines had a lower response rate to IV ketamine compared to those not on benzodiazepines. Benzodiazepines enhance GABA-A receptor activity, which may partially counteract the glutamatergic mechanisms through which ketamine exerts its antidepressant effects. Some providers ask patients to skip their benzodiazepine dose on the day of treatment or to taper benzodiazepines before starting ketamine therapy, when clinically safe to do so. However, abrupt benzodiazepine discontinuation can be dangerous, so any changes must be made gradually under medical supervision. Learn more about [ketamine and benzodiazepine interactions](/safety/ketamine-and-benzodiazepines/).

Who should not receive ketamine therapy?

Ketamine therapy is contraindicated in several populations. Individuals with uncontrolled hypertension or unstable cardiovascular disease face elevated risk due to ketamine's sympathomimetic effects, which temporarily raise blood pressure and heart rate. Patients with active psychosis or a history of psychotic disorders such as schizophrenia should avoid ketamine, as it can exacerbate psychotic symptoms. Those with elevated intracranial pressure, as may occur with certain brain tumors or hydrocephalus, should not receive ketamine. Active substance use disorders involving ketamine or other dissociative drugs represent a relative contraindication. [Pregnant or breastfeeding women](/safety/pregnancy-lactation-considerations/) are generally advised against ketamine therapy due to insufficient safety data. Severe liver disease may impair ketamine metabolism and increase adverse effects.

Does lamotrigine interact with ketamine?

Lamotrigine, commonly prescribed for bipolar disorder and as an adjunctive treatment for depression, may attenuate ketamine's antidepressant effects. Lamotrigine works partly by inhibiting glutamate release, which could theoretically oppose ketamine's mechanism of action that involves a surge in glutamate signaling. A study by Anand and colleagues found that pretreatment with lamotrigine blocked some of ketamine's subjective and cognitive effects. However, the clinical significance of this interaction is still debated, and some patients taking lamotrigine do respond to ketamine therapy. Most providers do not recommend discontinuing lamotrigine solely for ketamine treatment, particularly in bipolar patients who depend on it for mood stabilization. The decision should be individualized.

Can I take ketamine if I use opioid medications?

Ketamine can generally be administered to patients taking opioid medications, but caution is warranted. Both ketamine and opioids are CNS depressants, and their combined sedative effects may be additive. Some research has suggested that opioid receptor signaling may be involved in ketamine's antidepressant mechanism, and a controversial study by Williams and colleagues found that naltrexone, an opioid antagonist, blocked ketamine's antidepressant effects, though this finding remains debated. For chronic pain patients on stable opioid regimens, ketamine is often used safely and may even provide an opioid-sparing analgesic effect. Dose adjustments and enhanced monitoring may be necessary. Patients on high-dose opioids or methadone maintenance should discuss the specific risks and benefits with both their pain management and ketamine providers.

Are there interactions between ketamine and blood pressure medications?

Ketamine transiently increases blood pressure and heart rate through sympathetic nervous system activation. Patients taking antihypertensive medications can generally receive ketamine therapy, and in fact their blood pressure medications may help buffer the transient cardiovascular effects. However, the interaction dynamics vary by medication class. Beta-blockers and clonidine may attenuate the cardiovascular response to ketamine. Calcium channel blockers and ACE inhibitors are generally compatible. Patients should take their blood pressure medications as prescribed on treatment days unless specifically instructed otherwise. Pre-treatment blood pressure is checked at every session, and treatment may be postponed if readings are significantly elevated. Close monitoring during and after infusion helps ensure cardiovascular safety.

Should I stop any supplements before ketamine treatment?

Certain supplements may interact with ketamine and should be discussed with your provider. St. John's Wort, a popular herbal antidepressant, affects multiple cytochrome P450 enzymes and can alter ketamine metabolism. Supplements with stimulant properties such as high-dose caffeine, ephedra, or certain pre-workout formulations may exacerbate ketamine's cardiovascular effects. Kava and valerian root have sedative properties that could potentiate ketamine's CNS depressant effects. CBD products, increasingly common among patients with depression and pain, may inhibit CYP3A4 and CYP2B6 enzymes involved in ketamine metabolism, potentially increasing drug levels. While most common supplements such as magnesium, omega-3 fatty acids, and standard multivitamins are not known to interact, full disclosure to your provider ensures the safest treatment experience.

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Drug Interactions and Contraindications

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Essential information about medications that may interact with ketamine therapy, who should avoid treatment, and how to safely manage concurrent medications.

February 20, 2026

drug-interactions contraindications SSRIs benzodiazepines medication-safety MAOIs

Drug Interactions and Contraindications

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