Penthrox® - "Green whistle"
![Penthrox - green whistle](../_img/Analg-Penthrox_2.jpg)
- Methoxyflurane (C3H4Cl2F2O) is a volatile fluorinated hydrocarbon
- Colourless liquid analgesic with a fruity odour
- Highly lipophilic and rapidly absorbed via inhalation
- Potentiated through GABA receptors & two-pore K+ channels
- Metabolised in liver (CYP450 isozymes):
- Metabolites include: Fluoride, oxalic acid,di-fluoromethoxyacetic acid, di-chloroacetic acid
- 60% excreted in urine: fluorine, fluoride & oxalic acid
- Remainder is exhaled
- Metabolites can cause renal damage at high concentrations
Indications
- Emergency patient controlled analgesia for conscious adults with trauma associated moderate/severe pain
- Max 2 x 3 mL doses in 24hrs and Max 15ml / week (potentially nephrotoxic)
Dosage
- Single dose of Penthrox is 3 mLs (one bottle)
- Up to 1 hour of analgesia if used intermittently
- Max. dose not to exceed 6 mLs (2 bottles)
Contraindications - CHECK
C - Clinically significant cardiac or respiratory disease
H - Hypersensitivity to methoxyflurane (or any fluorinated anaesthetic)
E - Established or Hx malignant hypertherima
C- Consciousness altered
K - Kidney (eGFR < 45mL/min or on nephrotoxic antibiotics) or liver disease
Administration
![Step 1](../_img/Analg-Penthrox_Instruct_1.gif)
![Step 2](../_img/Analg-Penthrox_Instruct_2.gif)
![Step 3](../_img/Analg-Penthrox_Instruct_3.gif)
![Step 4](../_img/Analg-Penthrox_Instruct_4.gif)
![Step 5](../_img/Analg-Penthrox_Instruct_5.gif)
![Step 6](../_img/Analg-Penthrox_Instruct_6.gif)
![Step 7](../_img/Analg-Penthrox_Instruct_7.gif)
![Step 8](../_img/Analg-Penthrox_Instruct_8.gif)