Common Side Effects (Expected at Therapeutic Doses)

These effects occur in a significant proportion of patients and are generally considered part of the normal ketamine experience:

Dissociation: A feeling of detachment from your body, surroundings, or sense of self. This is dose-dependent and a known pharmacological effect of ketamine. It typically peaks 30-60 minutes after troche placement and resolves within 90 minutes.

Nausea: Reported by 10-20% of patients, particularly during the first few sessions. Often improves with repeated use. Pre-treatment with ondansetron and fasting for 2-4 hours before sessions helps significantly.

Dizziness and lightheadedness: Common during peak effects and for up to an hour afterward. Stay seated or reclined and do not attempt to stand during this period.

Elevated blood pressure: Ketamine raises systolic blood pressure by approximately 10-25 mmHg temporarily. This resolves as effects subside and is generally not clinically concerning in patients with normal or well-controlled blood pressure.

Drowsiness: Many patients feel sleepy during the descent phase of a session. This is normal and may persist for 1-2 hours after effects otherwise resolve.

Bitter taste and oral numbness: Ketamine has a characteristically bitter flavor. Numbness of the tongue and mouth is expected and resolves within 30-60 minutes.

Uncommon Side Effects

These occur in a smaller percentage of patients:

Headache: Usually mild, responsive to acetaminophen. Report persistent or severe headaches to your provider.

Anxiety or agitation: Some patients experience paradoxical anxiety rather than relaxation, particularly early in treatment or at doses that produce uncomfortable dissociation. Dose adjustment often helps.

Vivid dreams: Unusually vivid or strange dreams on session days or the night after a session. Generally temporary and not harmful.

Blurred vision: Brief visual disturbance during peak effects. Should resolve fully as effects subside.

Muscle twitching: Involuntary muscle movements, typically mild and brief.

Rare but Serious Side Effects (Contact Provider or Seek Emergency Care)

Severe hypertension: Blood pressure above 180/110 with headache, vision changes, or chest pain. Call 911.

Prolonged altered mental status: If effects have not substantially resolved after 3-4 hours, contact your provider.

Urinary symptoms: Pain, urgency, frequency, or blood in urine. Report to your provider — this may indicate early bladder irritation.

Severe allergic reaction: Hives, swelling of face or throat, difficulty breathing. Call 911.

New psychotic symptoms: Hallucinations or paranoid thinking that persist after effects resolve. Contact your provider immediately.

When Side Effects Improve

Most common side effects are worst during the first 1-3 sessions and improve as your body adjusts to the medication. Nausea, in particular, tends to diminish significantly after the initial sessions. If side effects remain problematic after 3-4 sessions, discuss dose or formulation adjustments with your provider. Our article on what to do if you experience side effects provides a detailed response protocol.

References

Ketamine Safety and Tolerability in Clinical Trials — Systematic review of ketamine adverse events across clinical studies
StatPearls: Ketamine — Comprehensive clinical reference on ketamine side effects and safety profile
MedlinePlus: Ketamine — National Library of Medicine consumer drug information including side effect listings