Levomepromazine (methotrimeprazine) is an anti-psychotic used at low dose for the control of nausea and vomiting. When levomepromazine hydrochloride as Nozinan® is diluted with 0.9% sodium chloride at concentrations ranging from 0.13 to 6.25 mg/ml, and stored in polypropylene syringes, the drug is stable for at least 14 days.

Levomepromazine reduces histamine-induced bronchial hyperresponsiveness in asthmatics without significant sedation. We present two patients with acute asthma refractory to conventional therapy, who were treated with inhalation of 2.5 mg levomepromazine. Until controlled studies have been done, we suggest that inhalation of levomepromazine be restricted to patients with asthma refractory to conventional therapy.

The effect of inhaled levomepromazine (Nozinan, Veractil) on bronchial responsiveness to inhaled histamine was investigated in asthmatics. In a double blind, randomized controlled study, 12 asthmatics (FEV1% pred 52-96%, and PC20 histamine 1.01 mg/ml (geometric mean)) were challenged before and after inhalation of levomepromazine in three different doses. Before and after each inhalation of levomepromazine, PC20, FEV1, the continuous reaction time (CRT) and the subjective sedation score (VAS) were determined. A dose-dependent increase in PC20 was observed after inhalation of levomepromazine. PC20 was increased by up to 4.02 two-fold concentration differences (doubling), i.e. up to a 38-fold increase from the basic values. Inhalation of the two higher doses of levomepromazine had a small sedative effect evaluated from an increase in CRT and the VAS-score and corresponding to the plasma concentrations. We conclude that inhaled levomepromazine has a dose-dependent protective effect on histamine-induced bronchial hyperresponsiveness in asthmatics and that inhalation of levomepromazine was well tolerated. The mechanism by which levomepromazine acts on histamine-induced bronchial hyperresponsiveness is not known but it could be partly explained by the antihistaminic effect. In this respect levomepromazine bears comparison with the most potent second generation antihistamines. The plasma concentrations of levomepromazine measured corresponded to those seen after oral intake of 5-10 mg levomepromazine.

To compare the effectiveness of IM administration of methotrimeprazine, a non-narcotic, nonaddicting phenothiazine derivative, with that of a combination of meperidine and dimenhydrinate in the treatment of severe migraine.Double-blind, randomized, controlled trial.University hospital emergency department.Consecutive adult patients with migraine who met eligibility criteria.Random allocation to receive IM injections of either 37.5 mg methotrimeprazine (Levoprome, Nozinan) or 75 mg meperidine (Demerol) combined with 50 mg dimenhydrinate (Dramamine, Gravol).The 37 patients in each group who completed the study were similar in all demographic and clinical characteristics. There were no statistical differences in pain intensity one hour after treatment, change in pain intensity, or pain relief as measured on a visual-analog scale; need for additional analgesia; persistence of nausea or vomiting; adverse effects; or follow-up status, except for prolonged drowsiness, in the group receiving methotrimeprazine.Methotrimeprazine is comparable to meperidine with dimenhydrinate for treating severe migraine and may be considered an effective, nonaddicting, IM alternative to narcotics for the management of this problem.

Ten patients with bronchial asthma were challenged with histamine before and after receiving saline and active drug (levomepromazine or antazoline) (a total of six challenges). The antihistaminic effect of levomepromazine (25 mg) was found to be comparable to that of antazoline (100 mg), evaluated from skin prick tests. Prechallenge forced expiratory volume in one second (FEV1) was found to be larger after levomepromazine than after antazoline (p less than 0.05), indicating a direct bronchodilating effect. This increased threshold airway calibre may have influenced the results of challenge, but change in provocative concentration producing 20% fall (PC20) was not statistically significantly correlated to change in FEV1. Levomepromazine increased PC20 2-doubling concentration compared to antazoline (p less than 0.05). Variation was observed in two minutes' ventilation during tidal volume breathing challenge. However, there was no statistically significant variation in two minutes' ventilation during challenge after receiving levomepromazine or antazoline. It was concluded that levomepromazine possesses a bronchodilating capacity and reduces bronchial hyperreactivity.