Therapeutic agent for treating atherosclerosis of mammals

A method for treating atherosclerosis in mammals which comprises administering to a mammal an atherosclerosis-inhibiting effective amount of a fluorescent tetrapyrrole compound that accumulates in an atherosclerotic lesion within said mammal and applying light of sufficient wavelength and intensity to produce a cytotoxic effect on said atherosclerotic lesion, wherein said compound is of the formula:

• ##STR15## or a corresponding dihydrotetrapyrrole or tetrahydropyrrole carboxylic acid;
• or corresponding monoamides, diamides and polyamides of said tetrapyrrole carboxylic acid with an aminomonocarboxylic acid or a dicarboxylic acid;
• or pharmacologically acceptable salts thereof;
• wherein:
• R.sub.1 is methyl, ##STR16## R.sub.2 is H, vinyl, ethyl, --CH(OH)--CH.sub.3, acetyl, ##STR17## R.sub.3 is methyl, ##STR18## R.sub.4 is H, vinyl, ethyl, --CH(OH)--CH.sub.3, --CH.sub.2 --CH.sub.2 --COOH, .dbd.CHCHO, or ##STR19## R.sub.5 is methyl;
• R.sub.6 is H, --CH.sub.2 --CH.sub.2 --COOH, --CH.sub.2 --CH.sub.2 --COOR or COOH;
• R.sub.7 is --CH.sub.2 --CH.sub.2 --COOH, --CH.sub.2 --CH.sub.2 --COOR or ##STR20## R.sub.8 is m ethyl or ##STR21## R.sub.9 is H, --COOH, --CH.sub.2 --COOH or methyl;
• provided that when R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.7 and R.sub.8 are each two substituents or when R.sub.1, R.sub.2, R.sub.3, R.sub.7 and R.sub.8 are divalent and attached to the same carbon, the pyrrole ring is a dihydropyrrole;
• R is a lower alkyl or benzyl;
• R.sub.6 and R.sub.9 when taken together are --CO--CH.sub.2 -- or ##STR22## with the proviso that at least one of R.sub.1 to R.sub.9 is a free carboxyl group.