PENICILLIN-G (BENZYL PENICILLIN)

It is narrow spectrum with limited activity against gram positive bacteria. Many bacteria are inherently insensitive to PnG because in them the target enzymes and penicillin binding protein are located deeper under lipoprotein barrier where PnG is unable to penetrate.

Indications

Streptococcal infections like Pharyngitis, otitis media,scarlet fever, rheumatic fever. Pneumococcal infections like otitis media, meningitis, osteomyelitis. Gonorrhoea. Syphilis, Diphtheria, Tetanus, gas gangrene, Trench mouth, Rat bite fever.

Dosage

Sod. Penicillin G. infection : 0.5-5 MU i.m./i.v 6-12 hrly. Pot Penicillin-G oral use : 2-8 lac U Q.I.D. 1 hr before or 2 hrs after food.

Contra-Indications

Hypersensitivity, Allergic diathesis, rash, itching, urticaria, fever, wheezing, angioneurotic edema.

Special Precautions

A scratch test or intradermal test may be performed first.

Side Effects

Pain at i.m injection site, nausea on oral ingestion, mental confusion, muscular twitchings, convulsions, coma, CNS stimulation, hallucinations, convulsions

Drug Interactions

Probenecid Increases and prolongs blood levels. Effects reduced by bacteriostatic agents like Chloramphenicol and tetracycline.