Ketamine Induced Nausea and Vomiting: Tips and Prevention

A Manageable Side Effect

Nausea is one of the most commonly reported side effects of ketamine therapy. The good news: it's well understood, predictable, and highly manageable. Most patients who experience it find that simple preventive measures reduce or eliminate it entirely.

Why Nausea Occurs

Four mechanisms contribute to ketamine-related nausea:

Central nervous system effects — Ketamine affects brainstem receptors involved in the nausea reflex. Its dissociative properties alter sensory processing, which can trigger queasiness.

Vestibular disruption — Similar to motion sickness, ketamine impacts the inner ear's balance system. This is why movement during a session can make nausea worse.

Gastrointestinal irritation — When sublingual ketamine residue is swallowed rather than absorbed through the oral mucosa, it can irritate the stomach lining directly.

Autonomic activation — Stimulation of the sympathetic nervous system affects gut motility.

When It Typically Occurs

Nausea follows predictable patterns during a session:

Episodes typically resolve within 15–30 minutes.

Prevention Strategies

Fasting (Most Important)

Abstain from food for 4–6 hours before your session. This is the single most effective preventive measure. Clear liquids are usually fine up to 2 hours before.

Anti-Nausea Medication

Ondansetron (Zofran) blocks serotonin receptors that trigger nausea. Take 4–8mg about 30–60 minutes before your session. Your provider can prescribe this alongside your ketamine.

Natural Remedies

Ginger — tea, chews, or capsules — is a well-studied anti-nausea agent. It accelerates gastric emptying and complements pharmaceutical options well. Many patients find ginger tea before a session both calming and effective.

Tablet Management

If you're using sublingual ketamine, spit out residue rather than swallowing it. This minimizes stomach irritation and actually improves bioavailability by keeping the medication in contact with oral tissue.

Body Positioning

• Remain reclined with eyes closed during the session
• Minimize head movement
• Rise gradually afterward
• Avoid sudden position changes

When to Contact Your Provider

Reach out if you experience:

• Vomiting that prevents you from keeping fluids down
• Nausea lasting beyond 4–6 hours after a session
• Nausea between sessions that wasn't present before treatment
• Severe abdominal pain
• Symptoms worsening despite following preventive measures

Perspective

Nausea from ketamine therapy is temporary, predictable, and rarely severe enough to outweigh the treatment's benefits. Most patients find that consistent fasting and anti-nausea medication make it a non-issue after the first session or two.

For a broader overview of what to expect, see risks and side effects of ketamine treatment. For session preparation details, see how to safely take ketamine.