Methoxyflurane

Question 1

What is the presentation of Methoxyflurane?

Answer 1

3mL in bottle

Question 2

What is the pharmacology of Methoxyflurane?

Answer 2

Inhalational analgesic agent at low concentrations.

Question 3

How is Methoxyflurane metabolised and excreted?

Answer 3

Metabolised by the liver.

Excreted by the lungs.

Question 4

List the PEI for Methoxyflurane.

Answer 4

1. Pain relief

Question 5

List the contraindications for Methoxyflurane.

Answer 5

1. Pre-existing renal disease/renal impairment
2. Concurrent use of tetracycline antibiotics
3. Exceeding a total dose of 6mL/24hrs
4. Personal or family Hx of malignant hyperthermia
5. Muscular dystrophy

Question 6

List the precautions for Methoxyflurane.

Answer 6

1. Must be hand-held so that it can fall away from pt face if unconsciousness occurs. Operator may assist but should monitor consciousness.
2. Pre-eclampsia
3. Concurrent use with oxytocin may cause hypotension

Question 7

List the side effects of Methoxyflurane.

Answer 7

1. Drowsiness
2. Decrease in BP and bradycardia (rare)
3. Renal toxicity may occur if max. dose 6mL/24hrs exceeded

Question 8

What are the special notes for Methoxyflurane?

Answer 8

1. Max initial priming dose is 3mL and will last 25mins. After this, an additional dose of 3mL may be administered.
2. Analgesia commences after 8 - 10 breaths and ceases 3 - 5 minutes after being discontinued.
3. Do not administer in confined space - ensure adequate ventilation.
4. Malignant hyperthermia is a rare condition that can be triggered by volatile anaesthetics - ask about PHx/family PHx of rxns to inhaled anaesthetics.
5. In pts with muscular dystrophy, volatile agents may precipitate life-threatening rhabdomyolysis.

Question 9

When does analgesia commence, last for and cease with Methoxyflurane?

Answer 9

Commences: after 8 - 10 breaths
Lasts 25mins
Ceases: 3 to 5 minutes after discontinuation