Ketamine

Ketamine is a dissociative anesthetic that produces a sense of detachment from the body and environment. At low doses, it causes euphoria, altered perception, and a floating sensation. At higher doses, it produces the 'K-hole' — a profound dissociative state resembling an out-of-body or near-death experience. Used medically as an anesthetic and increasingly for treatment-resistant depression (as Spravato/esketamine).

How It Works

Primarily blocks NMDA glutamate receptors, reducing excitatory neurotransmission. Also affects opioid, monoaminergic, and cholinergic systems. At sub-anesthetic doses, triggers a glutamate surge that enhances neuroplasticity (basis for antidepressant effects). Produces dissociation by disrupting communication between the cortex and limbic system.

Legal Status

Schedule III controlled substance in the US. Prescription medication (anesthetic, antidepressant as Spravato). Class B in UK. Widely available illicitly. Legal for medical use in most countries.

Dosage Guide (Insufflation)

Note: Dosing varies enormously between individuals. Street ketamine may be cut or may actually be other substances (2-FDCK, DCK). Tolerance develops rapidly with frequent use. K-hole dose is typically 1-2mg/kg insufflated.

Organ System Impacts

neurological — High

Profound dissociation from NMDA receptor blockade. Disrupts communication between cortex and limbic system. Neuroprotective at low doses. Possible Olney's lesions (brain vacuolization) documented in animals at sustained high doses — relevance to human recreational use debated.

renal — High

Ketamine cystitis — chronic use causes severe bladder inflammation, fibrosis, and shrinkage. Bladder capacity can reduce from ~500mL to <50mL. Causes urinary frequency, urgency, incontinence, and severe pain. Can be irreversible and may require surgical intervention.

gastrointestinal — Moderate

Nausea common. Chronic use causes biliary tract dilation and 'K-cramps' — severe upper abdominal pain from biliary spasm. Liver enzyme elevation with regular use.

hepatic — Moderate

Metabolized extensively by liver. Chronic use associated with elevated liver enzymes (transaminases) and biliary dilation. Hepatotoxicity possible with heavy chronic use.

cardiovascular — Moderate

Increases heart rate and blood pressure (sympathomimetic). Mild cardiovascular stimulation. Generally safe for healthy individuals. Useful medically because it maintains cardiovascular function unlike other anesthetics.

respiratory — Moderate

Respiratory depression at anesthetic doses. Maintains airway reflexes better than other anesthetics (why it's useful in emergency medicine). Combined with other depressants significantly increases respiratory risk.

ocular — Low

Nystagmus (rapid eye movements). Double or blurred vision. No permanent eye damage.

dermatological — Low

Minimal skin effects.

hematological — Low

No significant blood effects.

musculoskeletal — Low

Muscle relaxation and incoordination. Increased fall risk. No direct musculoskeletal damage.

Effects

Desired Effects

• Euphoria and mood elevation
• Floating, weightless sensation
• Dissociation from body — pain reduction
• Altered perception of time and space
• Enhanced music appreciation
• At higher doses: K-hole — profound, immersive dissociative experience (out-of-body, ego dissolution)
• Antidepressant afterglow lasting days to weeks
• Disinhibition and social ease at low doses

Negative Effects

• Nausea and vomiting
• Confusion and disorientation
• Anxiety, especially during come-up or unexpected K-hole
• Impaired motor function — stumbling, falling
• Bladder urgency/pain (especially with regular use)
• Cognitive impairment while intoxicated
• Frightening dissociative experiences at unintended high doses
• Temporary amnesia

Rare but Serious

• Aspiration — vomiting while incapacitated (can be fatal if alone)
• Respiratory depression at very high doses or with other depressants
• Severe bladder damage with chronic use (ketamine cystitis — can require surgical intervention)
• Biliary tract damage — 'K-cramps' (severe abdominal pain)
• Loss of consciousness in dangerous environments (falls, drowning)
• Psychotic episodes

Drug Interactions

Detection Times

Ketamine is not on standard 5 or 10-panel drug tests. Extended panels or specific tests are needed.

Urine

Requires extended panel or specific ketamine/norketamine test. Detection window: up to 5 days.

Blood

Short blood detection window. Detection window: up to 2 days.

Hair

Hair testing can detect ketamine. Detection window: up to 90 days.

Saliva

Oral fluid testing for recent use. Detection window: up to 2 days.

Harm Reduction Tips

• Test your supply — reagent testing (Mandelin: orange) and fentanyl test strips

• NEVER use alone — vomiting while dissociated is an aspiration risk

• Stay hydrated — dehydration worsens bladder effects

• Do not combine with alcohol, GHB, or opioids — respiratory depression and aspiration risk

• Start with small bumps (15-25mg) and wait 15 minutes before redosing

• Sit or lie down before dosing — ketamine causes severe incoordination

• If you or someone else loses consciousness, place in recovery position immediately

• Limit frequency: bladder damage (ketamine cystitis) is the most serious chronic risk and develops with regular use

• If you notice urinary frequency, urgency, or pain — STOP using immediately. This can become irreversible

• K-holes can be disorienting. Set and setting matter. Be somewhere safe with trusted people

• Don't drive for at least 4 hours after use

• K-cramps (severe upper abdominal pain) signal biliary tract damage — reduce or stop use

Withdrawal Symptoms

Severity: Moderate

Onset: 24-72 hours. Acute phase: 1-2 weeks. Psychological symptoms may persist for weeks to months in heavy users.

Physical

• Tremors and shaking
• Fatigue
• Loss of appetite
• Sweating

Psychological

• Cravings
• Anxiety and depression
• Cognitive fog
• Insomnia
• Emotional instability
• Dissociative flashbacks in heavy users

Emergency Information

Call 911 If:

• Person is unconscious and cannot be roused
• Vomiting while unconscious (aspiration risk — roll into recovery position IMMEDIATELY)
• Breathing is very slow, shallow, or stopped
• Blue lips or fingertips
• Seizures
• Combined with opioids/GHB and unresponsive

What To Do

1. If unconscious: recovery position IMMEDIATELY (on side, mouth facing down to prevent aspiration)
2. Monitor breathing — count breaths per minute (normal: 12-20)
3. Do not give food or drink if person is heavily dissociated or unconscious
4. Stay with the person — they may be frightened and confused
5. Speak calmly: 'You took ketamine. This will wear off. You are safe.'
6. Remove hazards — they cannot coordinate their body safely

What To Tell EMS

The patient took ketamine (approximately [amount] insufflated/injected/oral), [time] ago. Currently [conscious/unconscious]. Breathing rate: [number]. Any substances combined: [list]. Main concern: [aspiration/respiratory depression/abdominal pain/unresponsive]. Ketamine is an NMDA antagonist anesthetic.

Seek Help If

• Persistent severe abdominal pain ('K-cramps')
• Blood in urine or severe bladder pain
• Vomiting that won't stop
• Person is conscious but extremely confused and agitated beyond what's typical
• Symptoms lasting much longer than expected (4+ hours after last dose snorted)

Normal Discomfort

• Mild nausea during come-up
• Feeling 'wonky' and uncoordinated
• Mild confusion and disorientation
• Strange body sensations (numbness, floating)
• Involuntary eye movements (nystagmus)