Ketamine parenteral
- Drugs List
- Therapeutic Indications
- Dosage
- Administration
- Contraindications
- Precautions and Warnings
- Pregnancy and Lactation
- Side Effects
- Monograph
Presentation
Solution for injection containing ketamine hydrochloride.
Drugs List
Therapeutic Indications
Uses
Induction and maintenance of anaesthesia
Sedation for painless procedures - children
Sedation for surgical and diagnostic procedures
Unlicensed Uses
Neuropathic pain
Dosage
All doses are given in terms of ketamine base.
Adults
Single agent for general anaesthesia
Intravenous infusion
Induction: 0.5mg/kg to 2mg/kg.
Maintenance: 10microgram/kg/minute to 45microgram/kg/minute (approximately 1mg/minute to 3mg/minute).
The rate of infusion will depend on the patient's reaction and response to anaesthesia. The dose required may be reduced when a long acting neuromuscular blocking agent is used.
Intermittent intravenous injection
Induction: 1mg/kg to 4.5mg/kg over 60 seconds.
Maintenance: Half to the full induction dose.
Dosage in obstetrics: 0.2mg/kg to 1mg/kg.
Intermittent intramuscular injection
Induction: 6.5mg/kg to 13mg/kg.
Maintenance: Half to the full induction dose.
See Additional dosage for information about onset and duration of each dose.
For diagnostic manoeuvres not involving intense pain the initial dose should be 4mg/kg via intramuscular injection.
As an induction agent prior to other anaesthetic agents
See intravenous and intramuscular induction doses described under general anaesthesia. If ketamine has been administered intravenously and the other anaesthetic is slow-acting, a second dose of ketamine may be required 5 to 8 minutes following the initial dose. If ketamine has been administered intramuscularly and the other anaesthetic is rapid-acting, administration of the other anaesthetic may be delayed up to 15 minutes following the injection of ketamine.
As a supplement to other anaesthetic agents
The dose of ketamine is usually in the same range as the dosage described under general anaesthesia; however, the use of another anaesthetic agent may allow a reduction in the dose of ketamine.
Children
(See Dosage; Adult)
The following alternative dosing schedule may be suitable:
Sedation prior to invasive or painful procedures
By intravenous injection
Children 1 month to 18 years:
1mg/kg to 2mg/kg as a single dose.
Induction and maintenance of anaesthesia (longer procedures)
By intravenous administration
Children 1 month to 18 years:
Initially 0.5mg/kg to 2mg/kg.
Followed by: Continuous intravenous infusion of 10micrograms/kg/minute to 45micrograms/kg/minute adjusted according to response.
Induction and maintenance of anaesthesia (shorter procedures)
By intravenous injection over at least 60 seconds
Children 12 to 18 years:
1mg/kg to 4.5mg/kg adjusted according to response (2mg/kg usually produces 5 to 10 minutes of surgical anaesthesia)
Children 1 month to 11 years:
1mg/kg to 2mg/kg produces 5 to 10 minutes of surgical anaesthesia adjusted according to response.
By intramuscular injection
Children 1 month to 18 years:
4mg/kg to 13mg/kg (4mg/kg sufficient for some diagnostic procedures).
Adjusted according to response.
10mg/kg usually produces 12 to 25 minutes of surgical anaesthesia.
Neonates
The following alternative dosing schedule may be suitable
Induction and maintenance of anaesthesia (longer procedures)
By intravenous administration
Initially 0.5mg/kg to 2mg/kg by intravenous injection.
Followed by: Continuous intravenous infusion of 8micrograms/kg/minute adjusted according to response.
Up to 30micrograms/kg/minute may be used to produce deep anaesthesia.
Induction and maintenance of anaesthesia (shorter procedures)
By intravenous injection over at least 60 seconds
1mg/kg to 2mg/kg produces 5 to 10 minutes of surgical anaesthesia, adjusted according to response.
By intramuscular injection
4mg/kg usually produces 15 minutes of surgical anaesthesia, adjusted according to response.
Patients with Hepatic Impairment
Consider reduced dose in patients with cirrhosis or other hepatic impairment as prolonged duration of action may occur in these patients. Ketamine is metabolised by the liver therefore hepatic clearance is required to end the clinical effects.
Additional Dosage Information
Dose and rate of administration should be reduced in patients with hypovolaemia or cardiovascular disease.
Preoperative preparation
Ketamine has been used safely when the stomach was not empty but for elective surgery it is recommended that nothing be given by mouth for at least six hours prior to anaesthesia.
Atropine, hyoscine, glycopyrrolate or other drying agent should be given appropriately before induction to reduce the ketamine-induced hypersalivation.
Benzodiazepines (midazolam, diazepam, lorazepam or flunitrazepam) used as premedication or as an adjunct to ketamine have been effective in reducing the incidence of emergence reactions.
Onset and duration
Individual response to ketamine varies with the dose, route of administration, patient age and the use of other concomitant agents. The dose should be titrated against patient requirements.
The patient should be kept supported during intravenous administration because induction of anaesthesia is rapid.
An intravenous dose of 2mg/kg usually produces surgical anaesthesia within 30 seconds and the effects may last for 5 to 10 minutes.
An intramuscular dose of 10mg/kg usually produces surgical anaesthesia within 3 to 4 minutes and the effects may last for 12 to 25 minutes.
Return to consciousness is gradual.
Recovery
Following the procedure the patient should be observed but left undisturbed. This does not preclude the monitoring of vital signs.
The use of a benzodiazepine (diazepam) may be considered if the patient shows any indications of emergence delirium. A hypnotic dose of a thiobarbiturate may be used to terminate severe emergence delirium reactions. Recovery times may be prolonged by addition of these agents.
When ketamine is administrated on a outpatient basis, the patient should not be released until fully recovered and then accompanied by a responsible adult.
Administration
Administer by intravenous or intramuscular injection or by intravenous infusion.
Intravenous administration should be slow (e.g. over 60 seconds) in order to reduced the risk of respiratory depression.
Contraindications
Cerebral trauma
Cerebrovascular accident
Eclampsia
Hypertension
Porphyria
Pre-eclampsia
Raised intracranial pressure
Severe cardiac disorder
Precautions and Warnings
Acute alcohol intoxication
Predisposition to increased intracranial pressure
Upper respiratory tract infection
Abnormal liver function test
Breastfeeding
Cardiovascular disorder
Chronic alcoholism
Congestive cardiac failure
Dehydration
Drug misuse
Glaucoma
Hallucinatory states
Head trauma
Hepatic impairment
History of hallucinations
Hypovolaemia
Intracranial lesion
Ischaemic heart disease
Myocardial infarction
Ocular trauma
Pregnancy
Psychiatric disorder
Raised cerebrospinal fluid pressure
Seizures
Tachyarrhythmia
Thyroid dysfunction
Dose adjustment may be necessary in patients with hepatic impairment
Advise patient ability to drive or operate machinery may be impaired
Advise patient not to drive until they know how the medicine affects them
Advise patient this medicine is subject to driving restrictions
Incompatible with barbiturates and diazepam. Do not mix together in syringe
Intravenous injection should be administered over 60 seconds
Pharyngeal + laryngeal reflexes remain intact. Avoid mechanical stimulation
Resuscitation facilities must be immediately available
Treatment to be administered by or under supervision of specialist
Emergence delirium phenomena may occur during the recovery period
Monitor vital signs, respiration & cardiac function
Tolerance and dependence may occur
Not for long term use
Patient should avoid alcohol as effect may be potentiated
Emergence reactions may occur. The psychological manifestations vary in severity between pleasant dreams, vivid imagery, hallucinations, nightmares and emergence delirium (often consisting of dissociative or floating sensations). In some cases these states have been accompanied by confusion, excitement and irrational behaviour which a few patients recall as an unpleasant experience. Use with caution in patients with a history of hallucinations or nightmares. Emergence delirium phenomena may be limited if verbal and tactile stimulation of the patient is kept to a minimum during the recovery period. This does not preclude the monitoring of vital signs.
Ketamine produces dissociative anaesthesia characterised by a trance-like state and amnesia which may persist into the recovery period. There is often an increase in muscle tone and the patient's eyes may remain open for all or part of the procedure.
Purposeless and tonic-clonic movements of the extremities may occur during the course of anaesthesia. These movements do not imply a light plane and are not indicative of the need for additional doses of anaesthetic.
Use with caution in patients with respiratory impairment. If respiratory depression occurs, mechanical support of respiration is preferred over the administration of analeptics.
An elevation of blood pressure begins shortly after ketamine injection. This reaches a maximum with a few minutes and usually returns to pre-anaesthetic values with 15 minutes after injection.
Cystitis (including haemorrhagic cystitis, acute kidney injury, hydronephrosis and ureteral disorders) has been reported in patients receiving long term treatment after a time of 1 month to several years. Hepatotoxicity has also been observed in patients receiving treatment for longer than three days.
If the surgical procedure involves visceral pain pathways, ketamine should be supplemented with an agent which obtunds visceral pain.
Pregnancy and Lactation
Pregnancy
Use ketamine with caution during pregnancy.
The manufacturer does not recommend the use of ketamine during pregnancy with the exception of administration during surgery for abdominal or vaginal delivery. Ketamine crosses the placenta. Animal studies have shown reproductive toxicity. Some neonates exposed to ketamine at maternal intravenous doses greater than or equal to 1.5mg/kg during delivery have experienced respiratory depression and low Apgar scores requiring newborn resuscitation. Marked increases in maternal blood pressure and uterine tone have been observed at intravenous doses greater than 2mg/kg.
As ketamine can increase heart rate, blood pressure and uterine tone it is particularly contraindicated in cases of uterine hyperactivity and when foetal hypoxia is suspected during labour. High doses may depress foetal functions and thus distort foetal monitoring during parturition. Ketamine anaesthesia close to delivery may induce dose-related, transient toxicity (including depression of neonatal respiration) in newborns however these effects are usually avoided with the use of lower material doses. Furthermore, use in caesarean section has been linked to the occurrence of clinically important panic disorders.
Lactation
Use ketamine with caution during breastfeeding.
The manufacturer does not recommend the use of ketamine during breastfeeding. It has been suggested that breastfeeding should be avoided for at least 12 hours after use of ketamine. Schaefer concludes that neither the pharmacokinetic qualities connected to the drug nor clinical experience is a reason for additional interruption of breastfeeding (this also applies to anaesthesia for a caesarean delivery).
Effects on Ability to Drive and Operate Machinery
This class of medicine is in the list of drugs included in regulations under 5a of the Road Traffic Act 1988 (England and Wales). This medicine may be subject to police testing and has specified maximum blood levels for driving. When prescribing this medicine: Advise patient the medicine can affect cognitive function and is likely to affect ability to drive. Advise patient not to drive until they know how the medicine affects them. It is an offence to drive while under the influence of this medicine. However, a patient is not committing an offence (called 'statutory defence') if: 1.The medicine has been prescribed to treat a medical or dental problem and 2.The medicine has been taken according to the instructions given by the prescriber and/or in the information provided with the medicine and 3.The medicine was not affecting the ability to drive safely. For further guidance see https://www.gov.uk
Side Effects
Agitation
Airway obstruction
Altered liver function tests
Anaphylactic reaction
Anorexia
Anxiety
Apnoea
Arrhythmias
Behavioural disturbances
Bradycardia
Confusion
Cystitis
Delirium
Diplopia
Disorientation
Dream abnormalities
Dysphoria
Erythema
Excitement
Haemorrhagic cystitis
Hallucinations
Hypersalivation
Hypertension
Hypertonia
Hypotension
Increase in muscle tone
Increased heart rate
Increased intra-ocular pressure
Insomnia
Laryngospasm
Nausea
Nightmares
Nystagmus
Pain on injection
Psychotic reactions
Rash
Rash at injection site
Respiratory depression
Respiratory rate disturbances
Tachycardia
Tonic-clonic spasms
Vomiting
Overdosage
It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.
The following number will direct the caller to the relevant local centre (0844) 892 0111
Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( www.toxbase.org ) or if this is unavailable at the backup site ( www.toxbasebackup.org ).
Further Information
Last Full Review Date: April 2020
Reference Sources
Drugs During Pregnancy and Lactation: Treatment Options and Risk Assessment, 3rd edition (2015) ed. Schaefer, C., Peters, P. and Miller, R. Elsevier, London.
Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk, 10th edition (2015) ed. Briggs, G., Freeman, R. Wolters Kluwer Health, Philadelphia.
Martindale: The Complete Drug Reference. 39th Edition. London: Brayfield A (ed). Pharmaceutical Press; 2017.
Medications and Mothers' Milk, Sixteenth Edition (2014) Hale, T and Rowe, H, Hale Publishing, Plano, Texas.
Summary of Product Characteristics: Ketalar 50 mg/ml Injection. Pfizer Limited. Revised December 2019.
Summary of Product Characteristics: Ketamine 50 mg/ml Injection. hameln pharmaceuticals ltd. Revised October 2019.
National Institute for Health and Clinical excellence (NICE) clinical guidance 112: Sedation in under 19s: using sedation for diagnostic and therapeutic procedures. Issue date December 2010
Available at: https://www.nice.org.uk/CG112
Last accessed: 12 November 2015
Gov.uk. Government departments. Department for Transport. Publications. Drug driving and medicine: advice for healthcare professionals. Drug driving: Guidance for healthcare professionals on drug driving. Available at: https://www.gov.uk Last accessed: 11 April 2019
NICE Evidence Services Available at: www.nice.org.uk Last accessed: 11 February 2020
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