ketamine (Rx)

>10%

Emergence rxns

HTN

Increased cardiac output

Increased ICP

Tachycardia

Tonic-clonic movements

Visual hallucinations

Vivid dreams

1-10%

Bradycardia

Diplopia

Hypotension

Increased IOP

Injection-site pain

Nystagmus

<1%

Anaphylaxis

Cardiac arrhythmia

Depressed cough reflex

Fasciculations

Hypersalivation

Increased IOP

Increased metabolic rate

Hypertonia

Laryngospasm

Respiratory depression or apnea with large doses or rapid infusions

Postmarketing Reports

Genitourinary: Dysuria, increased urinary frequency, urgency, urge incontinence, hematuria, cystitis (including cystitis non-infective, cystitis interstitial, cystitis ulcerative, cystitis erosive, and cystitis hemorrhagic), hydronephrosis and reduced bladder capacity

Gastrointestinal disorders: Anorexia, nausea, vomiting, hepatobiliary dysfunction; biliary duct dilatation with or without evidence of biliary obstruction reported with recurrent use (eg, misuse/abuse or medically supervised unapproved indications)

Contraindications

Hypersensitivity

Conditions in which an increase in blood pressure would be hazardous

Cautions

Increases 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 used alone

May cause CNS depression; use caution when operating heavy machinery; do not engage in hazardous activities or operate hazardous machinery for at least 24 hr 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 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; 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 nonintubated and/or nonmechanically ventilated patients, appropriate equipment and qualified personnel should be immediately available to use appropriate equipment for rapid institution of respiratory and/or cardiovascular support

Too rapid administration will cause respiratory depression

Do NOT put diazepam or barbiturates in same syringe/bag

Safety for obstetric procedures not established

Children may require head positioning, supplemental oxygen, occasional bad-valve-mask ventilatory support and measures top 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

Therapy is associated with hepatobiliary dysfunction (most often a cholestatic pattern), with recurrent use (e.g., misuse/abuse or medically supervised unapproved indications); biliary duct dilatation with or without evidence of biliary obstruction also reported with recurrent use; obtain baseline LFTs, including alkaline phosphatase and gamma-glutamyl transferase, in patients receiving therapy as part of a treatment plan that utilizes recurrent dosing; monitor those receiving recurrent therapy at periodic intervals during treatment

Emergence reactions

• Postanesthetic emergence reactions, manifested as dreamlike state, vivid imagery, hallucinations, and/or delirium reported in ~12%
• Least common in children younger than 15 yr, elderly older than 65 yr, or when administered IM
• May occur up to 24 hr postoperatively
• Occurrence may be decreased by using 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 (ie, >3 hr) or multiple procedures

Pregnancy

There are no adequate and well-controlled studies performed in pregnant women; in animal reproduction studies in rats developmental delays (hypoplasia of skeletal tissues) were noted at 0.3 times the human intramuscular dose of 10 mg/kg; in rabbits, developmental delays and increased fetal resorptions were noted at 0.6 times the human dose; since safe use in pregnancy, including obstetrics (either vaginal or abdominal delivery), has not been established, such use is not recommended

Lactation

Not known if excreted in breast milk; effect on nursing infant unknown

Pregnancy Categories

A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

NA: Information not available.

Mechanism of Action

Produces dissociative anesthesia

Blocks NMDA receptor

Overdose may lead to panic attacks and aggressive behavior; rarely seizures, increased ICP, and cardiac arrest

Very similar in chemical makeup to PCP (phencyclidine), but it is shorter acting and less toxic

Absorption

Onset: 30 sec (IV); 3-4 min (IM)

Duration: 5-10 min (IV); 12-25 min (IM): dissociative state may last >20 min

Peak plasma concentration: 0.75 mcg/mL

Metabolism

Liver

Elimination

Excretion: Urine (91%), feces (3%)

IV Incompatibilities

Additive: Barbiturates, diazepam

Syringe: Barbiturates, diazepam, doxapram

IV Compatibilities

Additive: Morphine sulfate

Syringe: Bupivacaine with fentanyl, clonidine with tetracaine, lidocaine with morphine sulfate, meperidine, morphine tartrate

Y-site: Ceftazidime, propofol

IV Preparation

IV infusion: Prepare 1 or 2 mg/mL solution by adding 500 mg to 500 mL or to 250 mL, respectively, of D5W or NS

IV/IM Administration

Administer IM, OR

By slow IV injection over at least 60 sec

Do not give 100 mg/mL preparation undiluted

Storage

Store at controlled room temperature

Colorless to slightly yellow solution; may darken upon prolonged exposure to light but this does not affect potency

Do not use if precipitate is present

Protect from light