B. PHARM 6th SEM. PHARMACOLOGY
Q. 1. Classify semi synthetics penicillin discus pharmacology of ampicillins. (S 17, 18, 19) Classify semi synthetics penicillin
Acid-resistant alternative to penicillin G Phenoxymethyl penicillin (Penicillin V). 1 Penicillinase-resistant penicillins Methicillin, Cloxacillin, Dicloxacillin Extended spectrum penicillins (a) Aminopenicillins: Ampicillin, Amoxicillin. (b) Carboxypenicillins: Carbenicillin. (c) Ureidopenicillins: Piperacillin,
β-lactamase inhibitors: Clavulanic acid, Sulbactam, Tazobactam (S 19) Mechanism Enhancing the activity of aminopenicillins against β-lactamase producing pathogens Pharmacokinetics Not degraded by gastric acid; oral absorption is incomplete but
adequate. It is partly excreted in bile and reabsorbed enterohepatic circulation occurs. Excretion is kidney, but tubular secretion is slower than for PnG; plasma t1⁄2 is 1 hr.
Uses Urinary tract infections: Ampicillin has been the drug of choice for most acute infections
Respiratory tract infections: including bronchitis, sinusitis, otitis media, etc.
Meningitis: Ampicillin has been a first line drug, but a significant number of meningococci, pneumococci
Gonorrhoea: It is one of the first line drugs for oral treatment of nonpenicillinase producing gonococcal infections.
Adverse effects: Diarrhoea is frequent after oral administration. Ampicillin is incompletely absorbed the unabsorbed drug irritates the lower intestines as well as causes marked alteration of bacterial flora Spectrum Gram-negative bacilli, e.g. H. influenzae, E. coli, Proteus, Salmonella Shigella and Helicobacter pylori, Strep. viridans, enterococci and Listeria; equally active for pneumococci, gonococci and meningococci