Methoxyflurane inhalation vapour solution
- Drugs List
- Therapeutic Indications
- Dosage
- Administration
- Contraindications
- Precautions and Warnings
- Pregnancy and Lactation
- Side Effects
- Monograph
Presentation
Inhalation vapour, solution containing methoxyflurane.
Drugs List
Therapeutic Indications
Uses
Relief of moderate to severe pain
Dosage
The lowest effective dose to provide analgesia should be used.
Adults
The contents of one 3ml bottle of methoxyflurane, inhaled as required through the inhaler device.
Once completed, a further 3ml dose may be administered if further analgesia is required.
Maximum total dose of 6ml per treatment episode.
Administration on consecutive days is not recommended. The total weekly dose should not exceed 15ml.
Administration
Methoxyflurane should be self-administered under supervision of a person trained in its administration.
Patients should titrate the amount of methoxyflurane inhaled according to their current level of pain. Continuous inhalation provides analgesic relief for up to 25 to 30 minutes whereas intermittent inhalation may provide a longer analgesic effect.
The methoxyflurane inhaler should always be used with the Activated Carbon (AC) Chamber to reduce occupational exposure to methoxyflurane.
Contraindications
Children under 18 years
History of malignant hyperpyrexia
Impaired consciousness
Predisposition to malignant hyperthermia
History of hepatic impairment due to halogenated anaesthesia
History of hepatic impairment due to previous use of this drug
Respiratory depression
Severe circulatory insufficiency
Severe renal impairment
Precautions and Warnings
Anaesthesia
Elderly
Predisposition to hepatic disorder
Predisposition to renal disease
Breastfeeding
Hepatic disorder
Pregnancy
Renal impairment
Advise patient ability to drive or operate machinery may be impaired
Contains butylated hydroxytoluene - May irritate skin/eyes/mucous membranes
Treatment to be administered under the supervision of a specialist
Potential for drug abuse
Advise patient to avoid alcohol during treatment
Methoxyflurane should not be used as an anaesthetic agent and is licensed for emergency relief of moderate to severe analgesia in conscious adult patients only. The lowest effective analgesic dose of methoxyflurane should be used. Methoxyflurane causes significant nephrotoxicity at high doses when the recommended dose is exceeded, and when there are factors present that alter the rate of metabolism.
Methoxyflurane is not appropriate for chronic pain conditions.
Caution should be exercised if methoxyflurane is used more frequently than on one occasion every 3 months as it may increase the potential for hepatic injury.
Methoxyflurane may cause possible reduction in blood pressure in the elderly.
Healthcare professionals regularly exposed to patients using methoxyflurane inhalers should be aware of relevant safety guidelines.
Pregnancy and Lactation
Pregnancy
Use methoxyflurane with caution during pregnancy.
The manufacturer advises caution if methoxyflurane is used during pregnancy especially during the first trimester. At the time of writing there is limited published information regarding the use of methoxyflurane during pregnancy. Potential risks are unknown.
Lactation
Use methoxyflurane with caution during breastfeeding.
The manufacturer advises caution if methoxyflurane is used when breastfeeding. The presence of methoxyflurane in human breast milk and its effects on exposed infants are unknown.
Counselling
Advise patient to inhale intermittently to achieve adequate analgesia.
Advise the patient that if stronger analgesia is required that they can cover the dilutor hole on the AC chamber with a finger during use.
Advise patient to take the lowest possible dose to achieve pain relief.
Side Effects
Agitation
Altered consciousness
Amnesia
Anxiety
Blood pressure changes
Blurred vision
Chills
Choking
Cough
Depression
Diplopia
Dissociation
Dizziness
Drowsiness
Dry mouth
Dysarthria
Dysgeusia
Elevation of liver enzymes
Euphoria
Fatigue
Feeling abnormal
Feeling drunk
Flushing
Headache
Hepatitis
Hyperhidrosis
Hypotension
Hypoxia
Increase in blood urea nitrogen
Increased appetite
Jaundice
Lability of affect
Liver damage
Nausea
Nystagmus
Oral discomfort
Oxygen saturation decreased
Paraesthesia
Peripheral sensory neuropathy
Renal failure
Restlessness
Serum creatinine increased
Serum uric acid disturbances
Somnolence
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: February 2020
Reference Sources
Summary of Product Characteristics: Penthrox 3mL inhalation vapour, liquid. Galen Ltd. Revised December 2018.
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