Comprehensive Guide to Ketamine: Uses, Dosage, Side Effects, and More

What is Ketamine?

Overview of Ketamine

Generic Name: Ketamine

Brand Name: Ketalar, Spravato (esketamine nasal spray), generics

Drug Group: Dissociative anesthetic (NMDA antagonist)

Commonly Used For

• Induce and maintain general anesthesia.
• Manage acute pain in emergencies.
• Treat treatment-resistant depression (TRD).

Key Characteristics

Form: Injectable solution (10 mg/mL, 50 mg/mL, 100 mg/mL), intranasal spray (esketamine 28 mg), or oral (off-label) (detailed in Dosage section).

Mechanism: Blocks NMDA receptors, producing dissociative anesthesia and rapid antidepressant effects.

Approval: FDA-approved (1970 for Ketalar); esketamine approved (2019 for TRD) and EMA-approved for specific indications.

Indications and Uses of Ketamine

Ketamine is indicated for a range of anesthetic, analgesic, and psychiatric conditions, leveraging its unique pharmacological profile:

General Anesthesia: Induces and maintains anesthesia in surgical procedures, particularly in resource-limited settings, per anesthesiology guidelines, supported by trials showing stable hemodynamics.

Acute Pain Management: Treats severe pain in trauma or burn patients, reducing opioid reliance, recommended in emergency medicine protocols with evidence of rapid onset.

Treatment-Resistant Depression (TRD): Alleviates depressive symptoms in TRD patients, with esketamine showing response rates of 50–70% within 24 hours, per psychiatry studies.

Post-Traumatic Stress Disorder (PTSD): Investigated off-label to reduce flashbacks and hyperarousal, with psychotherapy-enhanced outcomes, supported by trauma research.

Chronic Pain Syndromes: Managed off-label for neuropathic pain or fibromyalgia, improving quality of life, with pain management data.

Status Epilepticus: Explored off-label as a second-line treatment, controlling seizures, per neurology studies.

Sedation in Pediatrics: Used off-label for procedural sedation in children, with pediatric anesthesiology evidence.

Suicidal Ideation: Initiated off-label to reduce acute suicidal thoughts, with psychiatric emergency research.

Alcohol Withdrawal: Investigated off-label to manage severe agitation, with addiction medicine data.

Opioid-Sparing Anesthesia: Applied off-label to minimize intraoperative opioid use, with surgical anesthesiology studies.

Dosage of Ketamine

Dosage for Adults

General Anesthesia:

IV: 1–2 mg/kg for induction, followed by 0.5–1 mg/kg/hour for maintenance.

IM: 6.5–13 mg/kg for induction, with effects lasting 10–20 minutes.

Acute Pain Management:

IV: 0.1–0.5 mg/kg over 10–15 minutes, repeated every 1–2 hours as needed.

IM: 0.5–1 mg/kg every 4–6 hours.

Treatment-Resistant Depression (TRD):

Intranasal (Esketamine): 56 mg or 84 mg twice weekly for 4 weeks, then tapered, under psychiatric supervision.

Dosage for Children (≥3 months)

Procedural Sedation (Off-Label):

IV: 0.5–2 mg/kg, with maintenance doses of 0.25–0.5 mg/kg as needed.

IM: 4–6 mg/kg, adjusted based on age and weight, under pediatric oversight.

Dosage for Pregnant Women

Pregnancy Category B: Use only if benefits outweigh risks; consult an obstetrician and anesthesiologist, with fetal monitoring.

Dosage Adjustments

Renal Impairment: No adjustment needed for mild cases; reduce dose in severe impairment (CrCl <30 mL/min) and monitor.

Hepatic Impairment:

Mild to moderate (Child-Pugh A or B): Use cautiously with reduced dose; severe (Child-Pugh C): Avoid due to prolonged clearance.

Concomitant Medications: Adjust if combined with CNS depressants (e.g., benzodiazepines), increasing sedation risk; monitor respiratory status.

Elderly: Start with lower doses (e.g., 0.5 mg/kg IV); monitor for cardiovascular effects.

Psychiatric Use: Limit to supervised settings with follow-up to assess psychological impact.

Additional Considerations

• Administer this active ingredient in a controlled environment with resuscitation equipment available.
• Use intranasal esketamine with a 2-hour observation period post-dose for TRD.
• Avoid rapid IV bolus to minimize hemodynamic changes.

How to Use Ketamine

Administration:

IV: Infuse slowly over 1–2 minutes into a secure line, with continuous monitoring.

IM: Inject into a large muscle (e.g., deltoid or gluteal) for rapid effect.

Intranasal: Administer esketamine spray into alternating nostrils, following device instructions.

Timing: Administer as a single dose or continuous infusion based on procedure or condition, with TRD doses spaced per protocol.

Monitoring: Watch for respiratory depression, hypertension, or hallucinations; use pulse oximetry and ECG.

Additional Tips:

• Store at 20–25°C (68–77°F), protecting from light; refrigerate esketamine spray.
• Keep out of reach of children; restrict access due to abuse potential.
• Provide a quiet recovery environment to minimize emergence reactions.
• Educate patients on potential dissociative effects and need for a caregiver post-use.
• Schedule regular follow-ups for psychiatric patients to assess mood and side effects.

Contraindications for Ketamine

Hypersensitivity: Patients with a known allergy to Ketamine or its components.

Severe Hypertension or Heart Failure: Contraindicated due to cardiovascular stimulation risk.

Psychosis: Avoid in active schizophrenia or bipolar mania due to exacerbation risk.

Severe Liver Disease: Contraindicated in Child-Pugh Class C due to impaired metabolism.

Elevated Intracranial Pressure: Avoid in head injury or brain tumors due to increased pressure risk.

Severe Respiratory Depression: Contraindicated in patients with compromised airways.

Concurrent Use with MAOIs: Avoid within 14 days due to hypertensive crisis risk.

Warnings & Precautions for Ketamine

General Warnings

Respiratory Depression: Risk with high doses or rapid administration; monitor with capnography.

Emergence Reactions: Risk of hallucinations or agitation post-anesthesia; use benzodiazepines if needed.

Cardiovascular Stimulation: Risk of hypertension or tachycardia; assess cardiac status.

Increased Intraocular Pressure: Risk in glaucoma patients; avoid unless benefits outweigh risks.

Dependence Potential: Risk of psychological dependence with repeated use; limit to supervised settings.

Additional Warnings

Liver Injury: Rare elevation of liver enzymes; monitor hepatic function in chronic use.

Cognitive Impairment: Risk of memory issues with repeated doses; assess neuropsychiatric status.

Anaphylaxis: Rare severe allergic reactions; discontinue if swelling occurs.

Renal Impairment: Risk of accumulation; monitor creatinine in severe cases.

Hypersensitivity Reactions: Rare rash or bronchospasm; stop if severe.

Use in Specific Populations

Pregnancy: Category B; use with caution, monitoring fetal outcomes.

Breastfeeding: Use caution; monitor infant for sedation.

Elderly: Higher risk of cardiovascular effects; start with reduced doses.

Children: Safe for sedation with pediatric oversight.

Renal/Hepatic Impairment: Adjust or avoid based on severity.

Additional Precautions

• Inform your doctor about heart conditions, psychiatric history, or liver disease before starting this medication.
• Avoid alcohol or sedatives during therapy to reduce respiratory risk.
• Use protective measures (e.g., side rails) during recovery to prevent injury from agitation.

Overdose and Management of Ketamine

Overdose Symptoms

• Drowsiness, nystagmus, or hypertension.
• Severe cases: Respiratory arrest, coma, or cardiovascular collapse.
• Hallucinations, vomiting, or seizures as early signs.
• Profound sedation or death with extremely high doses.

Immediate Actions

Contact the Medical Team: Seek immediate medical help if overdose is suspected.

Supportive Care: Secure airway, provide oxygen, and support ventilation if needed.

Specific Treatment: No specific antidote; use benzodiazepines for agitation or physostigmine for severe hallucinations under specialist guidance.

Monitor: Check vital signs, oxygen saturation, and mental status for 24–48 hours.

Patient Education: Advise against self-administering and to store securely.

Additional Notes

• Overdose risk is high with recreational use; store in a locked location.
• Report persistent symptoms (e.g., confusion, irregular breathing) promptly.

Side Effects of Ketamine

Common Side Effects

• Hallucinations (10–20%, managed with benzodiazepines)
• Nausea (5–15%, relieved with antiemetics)
• Dizziness (5–10%, decreases with rest)
• Hypertension (3–8%, monitored with BP checks)
• Vomiting (2–6%, controlled with hydration)

These effects may subside with adaptation or dose adjustment.

Serious Side Effects

Additional Notes

Regular monitoring with ECG and respiratory support is advised during administration.

Patients with a history of substance abuse should be closely watched for dependence.

Report any unusual symptoms (e.g., chest pain, persistent hallucinations) immediately to a healthcare provider.

Long-term use requires liver function tests and psychiatric evaluations to assess cognitive impact.

Drug Interactions with Ketamine

This active ingredient may interact with:

• CNS Depressants: Increases sedation (e.g., opioids, benzodiazepines); monitor respiration.
• MAOIs: Enhances hypertensive risk; avoid within 14 days.
• Thyroid Hormones: Amplifies cardiovascular effects; use cautiously.
• Anticholinergics: Potentiates tachycardia; adjust dose.
• Antidepressants: May alter mood effects; monitor closely.

Action: Provide your healthcare provider with a complete list of medications.

Patient Education or Lifestyle

Pharmacokinetics of Ketamine

Absorption: IV (immediate), IM (peak 5–15 minutes), intranasal (peak 20–40 minutes); bioavailability ~20–50% (oral).

Distribution: Volume of distribution ~3 L/kg; 20–50% protein-bound.

Metabolism: Hepatic via CYP3A4 and CYP2B6 to norketamine (active metabolite).

Excretion: Primarily renal (as metabolites); half-life 2–3 hours.

Half-Life: 2–3 hours, with norketamine extending effects.

Pharmacodynamics of Ketamine

This drug exerts its effects by:

Blocking NMDA receptors, producing dissociative anesthesia and analgesia.

Increasing glutamate release, contributing to rapid antidepressant effects.

Exhibiting dose-dependent risks of psychosis and respiratory depression.

Storage of Ketamine

Temperature: Store at 20–25°C (68–77°F); protect from light.

Protection: Keep in original container, away from heat and humidity.

Safety: Store in a secure, locked location out of reach of children due to abuse risk.

Disposal: Dispose of unused vials or sprays per local regulations or consult a pharmacist.

Frequently Asked Questions (FAQs)

Q: What does Ketamine treat?
A: This medication treats anesthesia and depression.

Q: Can this active ingredient cause hallucinations?
A: Yes, hallucinations are common; report if severe.

Q: Is Ketamine safe for children?
A: Yes, for sedation with supervision.

Q: How is this drug taken?
A: Via IV, IM, or intranasal, as directed.

Q: How long is Ketamine treatment?
A: Varies by use, from single dose to weeks for depression.

Q: Can I use Ketamine if pregnant?
A: Yes, with caution; consult a doctor.

Regulatory Information

This medication is approved by:

U.S. Food and Drug Administration (FDA): Approved in 1970 (Ketalar) for anesthesia; 2019 (Spravato) for TRD.

European Medicines Agency (EMA): Approved for anesthesia and esketamine for TRD.

Other Agencies: Approved globally for anesthesia; consult local guidelines.

References

1. U.S. Food and Drug Administration (FDA). (2023). Ketalar (Ketamine) Prescribing Information.
   • Official FDA documentation detailing the drug’s approved uses, dosage, and safety.
2. European Medicines Agency (EMA). (2023). Ketamine Summary of Product Characteristics.
   • EMA’s comprehensive information on the medication’s indications and precautions in Europe.
3. National Institutes of Health (NIH). (2023). Ketamine: MedlinePlus Drug Information.
   • NIH resource providing detailed information on the drug’s uses, side effects, and precautions.
4. World Health Organization (WHO). (2023). WHO Model List of Essential Medicines: Ketamine.
   • WHO’s inclusion of Ketamine for anesthesia.
5. Journal of Clinical Psychiatry. (2022). Ketamine in Depression.
   • Peer-reviewed article on Ketamine efficacy (note: access may require a subscription).