[Plasma N-methylhistamine levels following intravenous administration of pipecuronium in man].

The half life of released plasma histamine (HA) is short but N-methylhistamine (N-MHA) which is a metabolite of HA has a longer life. Measuring both HA and N-MHA, it is possible to know the release of HA in the plasma. The purpose of this study was to ascertain the release of HA by pipecuronium (PPB) by measuring both HA and N-MHA in the plasma. Ten patients received 0.04 mg.kg-1 and other 10 patients received 0.08 mg.kg-1 of intravenous PPB. Plasma levels of HA and N-MHA were measured 1 minute before and 1, 3, 5 and 10 minutes after the administration of PPB. Release of plasma HA and N-MHA was not observed following administration of PPB. We concluded that PPB does not cause the release of histamine because there is no increase of the metabolite, N-MHA, of HA, and PPB can be used safely for patients with allergy.