Summary of study characteristics (RCTs)
| Study and country | Age | Population | Procedure | Group 1 (n) intervention | Group 2 (n) control | Additional pain relief |
| RCTs | ||||||
| Moss et al,18 Australia* | Mean age 45 years (range 18–84 years) | Patients aged 16 years or older referred for CTE from February 2008 to September 2009. No previous CTE | Nasoduodenal intubation for CTE | 3 mL methoxyflurane inhaler 10 breaths before procedure (n=30) | Scented saline placebo inhaler (n=30) | Local anaesthetic† |
| Nguyen et al,19 Australia‡ | Penthrox 51.4±1.1 versus sedation 54.9±1.1 years | 18–75 years old, ability to give informed consent and adequately use Penthrox inhaler | Colonoscopy | Up to 6 mL methoxyflurane 2 min before procedure (n=125) | Intravenous sedation§ (n=126) | No |
| Spruyt et al,20 Australia¶ | Methoxyflurane mean 61.3±10.44; placebo mean 58.2±12.8 | Age≥18 years, need for bone marrow biopsy, life expectancy greater than 1 month | Bone marrow aspiration and core biopsy | 3 mL methoxyflurane inhaler 1–2 min before procedure (n=49) | Scented saline placebo inhaler (n=48) | Local anaesthetic |
| Hayne et al,21 Australia and New Zealand* | Group 1 median age 66 (61–70); group 2 median age 66 (61–69) | Biopsy naïve and able to comply with study requirement | TRUSB | PILA+3 mL Penthrox inhaler (n=209) | PILA+3 mL 0.9% scented saline placebo inhaler (n=211) | Local anaesthetic** and oral analgesia |
| Twidale et al,17 New Zealand§ | Overall mean age 49 years (23–76) | Patients undergoing an outpatient hysteroscopy | Outpatient hysteroscopy—diagnostic and operative | 3 mL methoxyflurane during procedure (n=45) | Scented placebo inhaler during procedure (n=45) | No |
*Multicentre double-blind RCT.
†Topical lidocaine hydrochloride 50 mg/mL and phenylephrine hydrochloride 5 mg/mL in nostrils.
‡Multicentre non-blinded RCT.
§Sedation—intravenous midazolam and fentanyl (age<60: 2.5 mg midazolam and 100 μg fentanyl; age>60: 1.5 mg midazolam and 50 μg fentanyl).
¶Single-centre double-blind RCT.
**2.5 mL 2% lidocaine in each of the two sides of the base of prostate gland.
CTE, CT enteroclysis; PILA, periprostatic infiltration of local anaesthetic; RCT, randomised controlled trial; TRUSB, transrectal ultrasonography-guided biopsy of the prostate.