Peripherally acting anti-pruritic opiates

A method of preventing or treating a non-respiratory and non-analis pruritic condition in a mammal in need of such prevention or treatment comprising topically, orally or parenterally administering to said mammal an effective anti-pruritic amount of a pharmaceutical composition which stimulates opiate receptors on peripheral sensory neurons in the skin comprising a compound of formula I ##STR12## wherein M is ##STR13## wherein:

• ##STR14## is an azabicycloalkyl containing from 6 to 9 carbon atoms with at least 5 atoms in each ring and is unsubstituted or substituted with OR.sup.18 in which R.sup.18 is hydrogen or lower alkanoyl containing 2 to 7 carbons and OR.sup.18 is at the 5 position in 5-membered rings or the 5 or 6 position in 6-membered rings and is attached in the endo or exo configuration;
• Ar.sup.1 and Ar.sup.2 are either (i) or (ii) as follows:
• (i) each is independently selected from aryl and heteroaryl groups containing from 5 to 7 members in the ring, each is unsubstituted or substituted with one or more substituents selected from halo, haloalkyl, hydroxy, alkyl, alkyloxy, aminosulfonyl, alkylcarbonyl, nitro, haloalkyl, trifluoromethyl, amino, aminocarbonyl, phenylcarbonyl or thienyl, where the alkyl groups are straight or branched chains lower alkyl containing from 1 to 6 carbon atoms;
• or
• (ii) Ar.sup.1 and Ar.sup.2 are each independently phenyl or pyridyl groups and with the carbon to which they are commonly linked form a fused ring so that the compounds of formula (I) have the structure:
• ##STR15## wherein n is 0 to 3;
• R.sup.2 is either alkyl in which the alkyl group is a straight or branched chain having 1 to 12 carbon atoms, or is alkylene having 1 to 6 carbon atoms with one or two double bonds;
• R.sup.3 is Ar.sup.3,--Y--Ar.sup.3, where Y is alkylene or alkyl having 1 to 3 carbon atoms, or is ##STR16## R.sup.8 is hydrogen or alkyl that is a straight or branched chain containing from 1 to 6 carbon atoms;
• Ar.sup.3 is aryl or heteroaryl containing from 5 to 7 members in the ring, which is unsubstituted or substituted with one or more substituents of halo, halo lower alkyl or lower alkyl;
• Ar.sup.4 is either:
• (i) is a heterocycle containing one to three fused rings or which is unsubstituted or substituted with one or more substituents selected from halo, halo lower alkyl or lower alkyl, or
• (ii) Ar.sup.4 is a radical of formula:
• ##STR17## in which R.sup.10, R.sup.11 and R.sup.12 are each independently selected from hydrogen, alkyl, alkyloxy, alkoxyalkyl, halo, haloalkyl, hydroxy, cyano, nitro, amino, alkylamino, di(alkyl)amino, aminocarbonyl, arylcarbonylamino, alkylcarbonylamino, alkylcarbonyl, alkylcarbonyloxy, aminosulfonyl, alkylsulfinyl, alkylsulfonyl, alkylthio, mercapto, C.sub.3 -C.sub.6 alkenyloxy, arylalkyloxy, aryloxy or alkyl, in which each group is unsubstituted or substituted with one or more halo atoms, halo alkyl or alkyl, and the alkyl groups are straight or branched chains that are lower alkyl;
• R is hydrogen, alkyl, halo, haloalkyl or OR.sup.9 ;
• R.sup.9 is selected from alkyl, arylalkyl, alkylcarbonyl, aminoalkyl, alkylaminoalkyl or dialkylaminoalkyl, in which the alkyl groups are straight or branched chains containing 1 to 12 carbon atoms;
• R.sup.4 is selected from among:
• (i) 5- to 7-membered aryl groups, which are unsubstituted or substituted with lower alkyl, halo lower alkyl or halo, or
• (ii) heterocyclic rings, containing one to three heteroatoms, that are unsubstituted or substituted with halo, halo lower alkyl or lower alkyl, or
• (iii) alkyl containing from 1 to 8 carbon atoms, alkenyl containing 3 to 6 carbon atoms, cycloalkyl containing from 3 to 6 carbon atoms, cycloalkyl alkyl in which the first alkyl contains 3 to 6 carbons and the second containing 1 to 3 carbons, or cycloalkenyl containing 4 to 7 carbons, or ##STR18## where R.sup.5 and R.sup.6 are either:
• (i) independently selected from hydrogen, alkyl, which is a straight or branched chain containing 1 to 12 carbon atoms, alkenyl, which is straight or branched chain, containing 1 to 12 carbon atoms and one or two double bonds, or aryl, which contains 5 to 7 carbon atoms, or
• (ii) R.sup.5 and R.sup.6 are selected from carbon chains, heteroatoms, and carbon chains containing one or more heteroatoms, so that with the nitrogen atoms to which each is attached they form a 3- to 7-membered heterocyclic ring containing one to three heteroatoms that is unsubstituted or substituted with halo, halo lower alkyl or lower alkyl;
• and
• R.sup.7 is selected from among:
• H;
• OH;
• --R.sup.14 OR.sup.13 in which R.sup.13 is hydrogen or lower alkyl, alkanoyl containing 2 to 5 carbon atoms, and R.sup.14 is lower alkenyl or lower alkyl;
• --CH.sub.2 NR.sup.15 R.sup.16 in which R.sup.15 is hydrogen, lower alkyl or lower alkanoyl and R.sup.16 is hydrogen or lower alkyl;
• OR.sup.15 ;
• R.sup.22 OR.sup.13, in which R.sup.22 is lower alkyl;
• --C(O)OR.sup.17 in which R.sup.17 is hydrogen, alkyl containing form 1 to 7 carbons or alkenyl having 3-7 carbon atoms, aryl or heteroaryl;
• or an alkali metal or alkaline earth metal salt, in a pharmaceutically acceptable carrier.