A Therapeutic Trial of Three Penicillins Conducted in a Casualty Department

There is at present considerable interest in the newer forms of penicillin which ha^ been introduced since the isolation of the penicillin nucleus 6-amino penicillanic in 1959 made possible, by substitution of differing side chains, the production of 3 whole range of new penicillin compounds. This trial was designed to compare the clinical effectiveness of two of these, phenethicillin and propicillin with crystalHne penicillin G given by injection. The antibiotic spectra of all three penicillins are con1' parable though not identical. Propicillin is also known as P.A. 248 (Ultrapen) and B.R.L. 284 (Brocillin). ^ts chemical name is alpha phenoxypropyl penicillin potassium. Studies by Williams011 et al. (1961) have shown it to be better absorbed after oral administration tha11 phenethicillin or penicillin V, and they considered it to be the drug of choice in strep*0' coccal infections. For penicillin-sensitive staphylococci all three were equally effective but against penicillin-resistant staphylococci propicillin was shown to be more effective in vitro, and since it gives the highest blood levels, it "was felt that it would be leaS likely of the oral penicillins to permit the emergence of penicillin-resistant staphyl0' cocci. Jackson and Rao (1961) also showed that propicillin owed its effectiveness against penicillin-resistant staphylococci to its greater resistance to the hydrolytlC effect of staphylococcal penicillinase on the penicillin molecule. Propicillin is acti^e in the presence of protein, is non-toxic and apparently no more likely than other penicillins to produce hypersensitivity reactions. In addition it is acid-stable, pr?' ducing adequate serum levels after oral administration, and its activity against Grain' positive cocci is comparable to penicillin V and phenethicillin. It is not effective agains Gram-negative bacteria (Knox, 1962). ,