Before a ketamine treatment, you need to avoid eating, drinking, taking certain medications, and consuming alcohol or other substances that could interfere with either safety or effectiveness. Most clinics will give you a preparation checklist, but the specifics behind each restriction matter, especially if you’re taking psychiatric medications that can blunt ketamine’s therapeutic effects.
Food and Drink Restrictions
Ketamine can cause nausea, and having food in your stomach increases both the likelihood and severity. The standard guidance from major treatment centers like Memorial Sloan Kettering is to stop eating solid food after midnight the night before your appointment. Clear liquids (water, broth, black coffee, apple juice) are allowed from midnight until two hours before treatment. Starting two hours before your session, nothing by mouth at all.
These fasting windows mirror what’s used before procedures involving sedation. Ketamine can suppress protective reflexes, so an empty stomach reduces the small but real risk of aspiration, where stomach contents enter the airways. If your appointment is later in the day, your clinic may adjust the fasting window, but the two-hour minimum for liquids and six to eight hours for solid food is standard.
Benzodiazepines Can Reduce Effectiveness
This is one of the most well-documented interactions in ketamine treatment for depression. Benzodiazepines, the class of anti-anxiety medications that includes lorazepam, diazepam, clonazepam, and alprazolam, repeatedly shorten and weaken ketamine’s antidepressant effects in clinical studies.
The numbers are striking. In one case report, a patient’s antidepressant response jumped from lasting 2 to 3 days to lasting 10 to 14 days after their benzodiazepine was withdrawn. Across larger studies, patients taking benzodiazepines took significantly longer to respond to ketamine, took longer to reach remission, and relapsed faster once they did respond. Higher doses predicted outright nonresponse: patients who didn’t respond to ketamine were taking an average dose four times higher than those who did respond.
The reason appears to be pharmacological. Benzodiazepines work by increasing inhibitory signaling in the brain, which directly counteracts the burst of excitatory activity that ketamine triggers. That excitatory surge is believed to be central to how ketamine rapidly lifts depression. Animal studies have confirmed that diazepam blocks ketamine’s ability to boost metabolism in mood-related brain regions and blocks ketamine-triggered dopamine release.
If you’re currently prescribed a benzodiazepine, don’t stop it on your own. Talk to your prescriber and your ketamine provider about whether tapering or skipping a dose before treatment is appropriate. The timing and safety of any adjustment depends on your dose, how long you’ve been taking it, and your seizure risk.
Lamotrigine Timing
Lamotrigine, commonly prescribed for bipolar disorder, has a complicated relationship with ketamine. Multiple clinical studies have tested single 300 mg doses of lamotrigine given two to five hours before ketamine infusions, and the drug appears to dampen some of ketamine’s psychological effects. This has led some clinics to recommend holding your lamotrigine dose the morning of treatment or adjusting timing. Your provider should give you specific guidance based on your dose and diagnosis.
Alcohol
Alcohol and ketamine share several targets in the brain, and combining them creates compounding risks. Both substances depress the central nervous system, so residual alcohol in your system during a ketamine session can intensify sedation and increase the risk of respiratory depression and cardiovascular stress.
There’s also a metabolic competition. When your body is processing a large amount of alcohol, it can slow ketamine’s breakdown, leading to higher and longer-lasting ketamine levels than intended. Most clinics ask patients to avoid alcohol for at least 24 hours before treatment. If you had several drinks the night before, mention it to your provider rather than hoping it won’t matter.
Blood Pressure Concerns
Ketamine temporarily raises blood pressure and heart rate. This is expected and usually manageable, but it means you should avoid anything that pushes your baseline blood pressure higher before your session. International consensus guidelines recommend that patients with a resting blood pressure above 140/90 should not proceed with treatment until it’s controlled. During an infusion, clinicians typically pause treatment if blood pressure climbs above 160/100.
Conditions that rule out ketamine treatment entirely include uncontrolled hypertension, recent heart attack, significant heart valve disease, and certain types of aneurysm. If you have any cardiovascular concerns, these should be discussed well before your first session, not on the day of treatment.
Caffeine raises blood pressure and heart rate on its own. While there’s no universal prohibition, clinical trials studying ketamine’s cardiovascular effects have excluded participants with excessive caffeine intake. If you’re sensitive to caffeine or already run on the higher side for blood pressure, skipping your morning coffee on treatment day is a reasonable precaution. Many clinics recommend this explicitly.
Stimulants and Recreational Drugs
Recreational stimulants like cocaine and MDMA raise heart rate and blood pressure, compounding ketamine’s cardiovascular effects and creating unpredictable interactions. Cannabis can intensify dissociative experiences in ways that make the session harder to manage therapeutically. As a general rule, avoid all recreational substances for at least 24 hours before treatment, and be honest with your provider about recent use.
If you take a prescribed stimulant for ADHD, ask your ketamine provider whether to skip your dose on treatment day. The concern is the same: additive effects on heart rate and blood pressure.
Violent or Stressful Media
This one surprises most people, but clinicians who run ketamine practices consistently report that what patients watch, read, or play in the hours before treatment shapes the experience. Ketamine induces a dissociative, often introspective state, and the emotional material already in your mind tends to surface during the session.
Patients who watched violent movies, played intense video games, or scrolled through distressing news before their appointment have reported more difficult or agitated experiences. The recommendation from experienced providers is to be intentional about your media consumption in the 12 to 24 hours leading up to treatment. Calming music, light reading, or time in nature are better choices than a true crime documentary or a heated social media feed.
Planning for After Treatment
Part of preparing well means planning for what comes after. You should not drive or operate heavy machinery for 24 hours following a ketamine session. Arrange a ride home before your appointment, not after. Most people feel groggy, spacially disoriented, or mildly “floaty” for several hours post-treatment, even if they feel mentally clear. The 24-hour window accounts for subtler impairments in reaction time and judgment that may not be obvious to you.
Clear your schedule for the rest of the day. Avoid making important decisions, signing contracts, or having emotionally loaded conversations. Treat the hours after ketamine the way you’d treat recovery from minor sedation: rest, hydrate, and give your brain space to process.