Ketamine

Ketamine is a general anesthetic indicated as the sole anesthetic agent for diagnostic and surgical procedures that do not require skeletal muscle relaxation. Ketamine hydrochloride is best suited for short procedures but it can be used, with additional doses, for longer procedures.

• Ketamine is indicated for the induction of anesthesia prior to the administration of other general anesthetic agents.
• Ketamine is indicated to supplement low-potency agents, such as nitrous oxide.
• Ketamine is available under the following different brand and other names: Ketalar.

Adult and Pediatric Dosage Forms & Strengths

Injectable solution: Schedule III

• 10mg/mL
• 50mg/mL/
• 100mg/mL/

Dosage Considerations -- Should Be Given As Follows:

Adult Anesthesia Induction

Load

• IV: 1-4.5 mg/kg slow IV once  
• Alternatively (off-label): 0.5-2 mg/kg slow IV if adjuvant drugs (eg, midazolam) are used, OR
• IM: 6.5-13 mg/kg IM once
• Alternatively (off-label): 4-10 mg/kg IM once if adjuvant drugs (eg, midazolam) are used

Maintenance

• 50% of IV ketamine induction dose administered PRN, OR
• 0.1-0.5 mg/min IV continuous infusion

Resistant Depression (Off-label)

• Infusion: 0.5 mg/kg IV twice weekly; not to exceed 6 weeks; therapy >6 weeks not studied

• ACEP recommends as safe in children
• 3 months or older

Intramuscularly (IM)

• 4-5 mg/kg IM once, ACEP Clinical Guidelines (Green 2004); may give a repeat dose (range 2-5 mg/kg) if sedation inadequate after 5-10 min or if additional doses are required 

Intravenously (IV)

• Various recommendations
• 1.5-2 mg/kg over 30-60 sec; may administer incremental doses of 0.5-2 mg/kg IV q5-15min PRN if initial sedation inadequate (Mace et al., Ann Emerg Med, 44: 342-377 [2004]), OR  
• 0.25-0.5 mg/kg (Harriet Lane)

Oral

• 6-10 mg/kg PO once; mix with 0.2-0.3 mL/kg of a beverage; give 30 min before procedure

16 years or older

Load

• IV: 1-4.5 mg/kg slow IV once
• Alternatively (off-label): 0.5-2 mg/kg slow IV if adjuvant drugs (eg, midazolam) are used, OR
• IM: 6.5-13 mg/kg IM once
• Alternatively (off-label): 4-10 mg/kg IM once if adjuvant drugs (eg, midazolam) are used

Maintenance

• 50% of IV ketamine induction dose administered as needed, OR
• .1-0.5 mg/min IV continuous infusion

Side effects associated with the use of ketamine include:

• Emergence reactions
• High blood pressure (hypertension)
• Increased cardiac output
• Increased intracranial pressure
• Fast or slow heart rate
• Seizures
• Visual hallucinations
• Vivid dreams
• Double vision
• Low blood pressure (hypotension)
• Increased intraocular (eye) pressure
• Injection site pain
• Involuntary eye movement

Less common side effects of ketamine include:

• Severe allergic reaction (anaphylaxis)
• Cardiac arrhythmia
• Depressed cough reflex
• Muscle twitching
• Increased salivation
• Muscle spasms
• Difficulty speaking or breathing
• Respiratory depression or apnea with large doses or rapid infusions

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.

If your doctor has directed you to use this medication, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

• Severe interactions of ketamine:
  • There are no known severe reactions associated with the use of ketamine.
• Serious interactions of ketamine include:
  • doxapram
  • elvitegravir/cobicistat/emtricitabine/tenofovir df
  • epinephrine
  • epinephrine racemic
  • fentanyl
  • fentanyl intranasal
  • fentanyl iontophoretic transdermal system
  • fentanyl transdermal
  • fentanyl transmucosal
  • idelalisib
  • isocarboxazid
  • ivacaftor
  • memantine
  • norepinephrine
  • phenelzine
  • phenylephrine po
  • rasagiline
  • selegiline
  • sodium oxybate
  • tranylcypromine
• Ketamine has moderate interactions with at least 171 different drugs.
• Mild interactions include:
  • amitriptyline
  • amoxapine
  • clomipramine
  • desipramine
  • dosulepin
  • doxepin
  • imipramine
  • lofepramine
  • maprotiline
  • mianserin
  • nortriptyline
  • protriptyline
  • trazodone
  • trimipramine

This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist. Check with your physician if you have health questions or concerns.

Warnings

• This medication contains ketamine. Do not take Ketalar if you are allergic to ketamine or any ingredients contained in this drug.
• Keep out of reach of children. In case of overdose, get medical help or contact a Poison Control Center immediately.

Contraindications

• Hypersensitivity.
• Conditions in which an increase in blood pressure would be hazardous.

Effects of Drug Abuse

• May cause dependence and tolerance with prolonged use

Short-Term Effects

• There are no short-term effects from the use of ketamine.

Long-Term Effects

• May cause dependence and tolerance with prolonged use; discontinuation of long-term use has been associated with a withdrawal syndrome with psychotic features.

Cautions

• Increases intracranial pressure (ICP) (head raising may alleviate); causes hypersalivation (may be controlled with atropine/glycopyrrolate).
• Not for use alone in surgery or diagnostic procedures of the pharynx, or bronchial tree, mechanical stimulation of the pharynx, larynx, or bronchial tree; avoid mechanical stimulation of the pharynx if ketamine is used alone.
• May cause central nervous system (CNS) depression; use caution when operating heavy machinery; do not engage in hazardous activities or operate hazardous machinery for at least 24 hours after anesthesia.
• May cause dependence and tolerance with prolonged use; discontinuation of long-term use has been associated with a withdrawal syndrome with psychotic features.
• Treat CNS abnormalities, CNS masses, or hydrocephalus as a relative contraindication, due to increased intracranial pressure produced by ketamine.
• Therapy may increase intraocular pressure, use with caution in patients with increased intraocular pressure; avoid use in patients with an eye injury or other ophthalmic disorder.
• Glaucoma or acute globe injury may be considered a relative contraindication.
• Therapy may enhance sympathomimetic effect; use caution in patients with porphyria or a thyroid disorder; may consider porphyria and thyroid disorder or thyroid therapy a relative contraindication.
• Use caution in patients with coronary artery disease, catecholamine depletion, hypertension, and tachycardia; monitor cardiac function continuously in patients with increased blood pressure, heart rate, and cardiac output, thereby increasing myocardial oxygen demand.
• Use caution in patients with cerebrospinal fluid pressure elevation; an increase in cerebrospinal fluid pressure may be associated with use.
• Use with caution in chronic alcoholic patients or acutely intoxicated.
• Use requires patient monitoring, to be administered only by experienced personnel who are not actively engaged in the procedure or surgery; in non-intubated and/or non-mechanically ventilated patients, appropriate equipment and qualified personnel should be immediately available to use appropriate equipment for the rapid institution of respiratory and/or cardiovascular support.
• Too rapid administration will cause respiratory depression.
• Do NOT put diazepam or barbiturates in the same syringe/bag.
• Safety for obstetric procedures not established.
• Children may require head positioning, supplemental oxygen, occasional bag-valve-mask ventilator support, and measures to address laryngospasm.
• Use caution in patients with significant LV dysfunction, as the sympathetic stimulation may not be adequate to overcome the negative inotropic effects, resulting in deterioration.

Emergence reactions

• Postanesthetic emergence reactions, manifested as dreamlike state, vivid imagery, hallucinations, and/or delirium reported in approximately12%
• Least common in children younger than 15 years, elderly older than 65 years, or when administered intramuscularly (IM)
• May occur up to 24 hours postoperatively
• An occurrence may be decreased by using a lower recommended dose in conjunction with a benzodiazepine for anesthesia induction

General anesthetics and sedation drugs in young children and pregnant women

• Brain development
  • Prolonged or repeated exposure may result in negative effects on fetal or young children's brain development
  • Assess the risk: benefit ratio in these populations, especially for prolonged procedures (i.e., greater than 3 hours) or multiple procedures

Pregnancy and Lactation

During pregnancy, use ketamine with caution if the benefits outweigh the risks. Animal studies show risk and human studies not available or neither animal nor human studies done. It is not known if ketamine is excreted in breast milk, and ketamine's effect on nursing infants is unknown. Consult your doctor.