The primary aim of the study is to show that methoxyflurane-lorazepam-percocet combination administrated 'per os' is non inferior to deep intravenous sedation in achieving analgesia during Rezum convective radiofrequency water vapor thermal therapy for the management of benign prostate hyperplasia (BPH). We propose to conduct a single-centered, unblinded, randomized controlled trial designed after consulting ICH Guidelines for Good Clinical Practice as well the regulations set by the Biomedical Research Ethics Board, University of Manitoba.

Participants who belong to the experimental arm will be given a single 'per os' dose of percocet (325mg acetaminophen + 7.5mg oxycodone) and lorazepam 1 mg, 30 minutes prior to the procedure. Patients will receive education on how to use the Penthrox inhaler device. Inside the operating room, the subject would self-inhale the methoxyflurane 5 minutes prior to the procedure. All these steps will be supervised by the clinical research nurse. Each participant will be administered with 3ml of methoxyflurane which is poured into the inhaler. Participants who were randomized to the control arm will receive deep intravenous sedation under the supervision of a trained anesthetist. A combination of midazolam, ketamine, remifentanil and propofol will be administered using an intravenous line. The quantity of these medications will be calculated by the anesthetist based on clinical judgement and also takes into account the physical characteristic of the subject. Both the groups receive the same Rezum water vapor therapy and the number of Rezum injections depends on the clinical judgement of the urologist performing the procedure. Immediately, post the procedure, the self-reported pain of the patient will be recoded using the NRS. A phone call follow-up would be done the following day to record any adverse events caused due to the procedure. Four weeks post the procedure, a phone call follow-up would be done to understand the patient satisfaction after the surgery.

Inclusion Criteria:

• Able to provide an informed consent.
• Age ≥ 18 years
• Biological males identified with male sexual organs.
• Scheduled for convective radiofrequency water vapor thermal therapy (REZUM) for the management of benign prostate hyperplasia.

Exclusion Criteria:

• Concomitant use of nephrotoxic and/or hepatoxic agents.
• Use of ≥ 6 ml Penthrox withing the previous 3 weeks.
• Known allergies and/or adverse events due to penthrox, other halogenated anesthetics, percocet (oxycodone + acetaminophen), lorazepam, lidocaine, midazolam, ketamine, remifentanil and propofol
• History of genetic susceptibility to malignant hyperthermia.
• Presence of clinically significant respiratory depression, cardiovascular instability, renal or hepatic impairment
• Altered level of consciousness due to any cause.