Penthrox 1.5ml & 3ml is a Prescription Medicine and should only be used by those trained in its use. PENTHROX 1.5 mL bottle contains 1.5 mL of Methoxyflurane 99.9% w/w. PENTHROX 3 mL bottle contains 3 mL of Methoxyflurane 99.9% w/w. Penthrox is indicated for the relief of pain in monitored conscious patients who require analgesia for surgical procedures.
Contraindications: Use as an anaesthetic agent, renal impairment, including reduced glomerular filtration rate (GFR), urine output and reduced renal blood flow. Renal failure, hypersensitivity to methoxyflurane, any fluorinated anaesthetics or to any ingredients in Penthrox. Cardiovascular instability, respiratory depression, head injury or loss of consciousness, a history of possible adverse reactions in either patient or relatives, malignant hyperthermia: patients with known or genetically susceptible to malignant hyperthermia.
Special warnings and precautions for use:
- Renal disease- Methoxyflurane impairs renal function in a dose-related manner due to the effect of the released fluoride on the distal tubule and may cause polyuric or oliguric renal failure, oxaluria being the prominent feature. Nephrotoxicity is greater with methoxyflurane than with other halogenated anaesthetics because of the slower metabolism over several days resulting in prolonged production of fluoride ions and metabolism to other potentially nephrotoxic substances. Methoxyflurane-associated renal failure is generally irreversible. Because of the potential nephrotoxic effects methoxyflurane must not be used as an anaesthetic agent. The risk is related to the total dose (time and concentration) and frequent exposure. Furthermore, the lowest effective dose of PENTHROX should be administered, especially in elderly or obese patients.
- Liver disease-It is not advisable to administer PENTHROX to patients who have shown signs of liver damage, especially after previous methoxyflurane or halothane anaesthesia. There have also been occasional reports of hepatic dysfunction, jaundice, and fatal hepatic necrosis associated with methoxyflurane use.
- Paediatric Use- Limited data is available regarding the administration of methoxyflurane using the PENTHROX Inhaler. The minimum effective dose to produce analgesia should be administered to children.
- Paediatric neurotoxicity- Some published studies in children have observed cognitive deficits after repeated or prolonged exposures to anaesthetic agents early in life.
- Diabetic patients,
- Use in elderly,
- Respiratory depression,
- Occupational exposure.
Interaction with other medicines and other forms of interaction: Enzyme inducing medicines, Adrenaline or noradrenaline, Medicines with nephrotoxic effects, Narcotics, β-blockers
Fertility, pregnancy and lactation: Use in Pregnancy (Category C). Published animal studies of some anaesthetic/analgesic/sedation medicines have reported adverse effects on brain development in early life and late pregnancy. Preeclampsia/ Toxaemia of pregnancy It is advisable not to administer PENTHROX due to the possibility of existing renal impairment. Breast-feeding Caution should be exercised when PENTHROX is administered to a nursing mother. Fertility No data available.
Effects on ability to drive and use machines: The decision as to when patients may again engage in activities requiring complete mental alertness, operate hazardous machinery or drive a motor vehicle must be individualised. Patients should be warned to take extra care as a pedestrian and not to drive a vehicle or operate a machine until the patient has completely recovered from the effects of the medicine, such as drowsiness. The treating doctor should decide when activities such as driving a vehicle or operating a machine may be resumed.
Undesirable effects: see Data Sheet for detailed list of possible undesirable effects as well as post marketing experience
For full information on dosage, contraindications, precautions, interactions and adverse effects please refer to the data sheet available at www.medsafe.govt.nz or by clicking on the link provided with this product. NZ Sponsor: Douglas Pharmaceuticals Ltd, AUCKLAND, NEW ZEALAND
NP21446 - Aug 2024