Self-administered nitrous oxide for the management of incident pain in terminally ill patients: a blinded case series.

The treatment of incident pain in terminally ill cancer patients receiving long-term opioid therapy remains a challenge. Self-administered inhaled nitrous oxide has been used for short-term analgesia in this setting, with mixed results. It is unclear whether nitrous oxide exhibits cross-tolerance with opioids, and there is the possibility of a strong placebo effect in previous unblinded reports. We report on a double-blind crossover case series, in which seven patients received either nitrous oxide/oxygen or a placebo air/oxygen mixture on each day of a two-day trial. Outcome indices were obtained before, during and after each use of the gas for anticipated incident pain. The patient population was very heterogeneous with respect to disease, pain scores and concurrent treatments. Nitrous oxide was beneficial during incidents in five of seven patients; the remaining two patients reported an overall preference for the nitrous oxide day. We conclude that a trial of self-administered inhaled nitrous oxide should be considered in patients with difficult incident pain.

Prophylaxis of postoperative nausea and vomiting with oral, long-acting dimenhydrinate in gynecologic outpatient laparoscopy.

UNLABELLED: Dimenhydrinate is an inexpensive antiemetic with few side effects available as an oral, long-acting (LA) formulation (Gravol L/A) containing 25 mg of immediate and 50 mg of sustained release drug. We designed this double-blind comparison trial to assess the efficacy of dimenhydrinate LA versus droperidol alone and the combination for prophylaxis of nausea, vomiting, and retching in outpatient gynecologic laparoscopy. One-hundred-forty-one women were randomized into 3 groups: 1) droperidol (placebo capsule preoperatively and IV droperidol 0.625 mg before induction), 2) dimenhydrinate LA preoperatively and IV placebo before induction, or 3) combination. Information regarding nausea, vomiting, retching, pain, and sedation was recorded in the postanesthesia care unit (PACU) and collected by telephone for the presence of symptoms: on arrival home; at bedtime; upon arising, and at lunchtime the following day. The overall incidence of complete treatment failure (rescue medication in PACU or nausea, vomiting, or retching at any time point) was 28 of 46 (61%), 28 of 48 (58%), and 22 of 47 (47%); and for treatment failure vomiting (rescue medication in PACU or vomiting or retching at any time point) was 16 of 46 (35%), 11 of 48 (23%), and 5 of 47 (11%), for the droperidol, dimenhydrinate, and combination groups, respectively (P = 0.007 for droperidol versus combination). There were no differences in sedation or pain. Preoperative administration of an oral dose of LA dimenhydrinate in combination with droperidol when compared with droperidol alone effectively reduced the incidence of vomiting but not nausea in women undergoing elective outpatient gynecologic laparoscopy. IMPLICATIONS: Dimenhydrinate is an inexpensive antiemetic with few side effects available as a long-acting oral formulation. Women undergoing outpatient gynecologic laparoscopy were given droperidol, an effective antiemetic, dimenhydrinate alone, or the combination of the two drugs. Dimenhydrinate plus droperidol significantly reduced the overall incidence of vomiting, but not nausea, when compared with droperidol alone.