CO
- 1. CO-TRIMOXAZOLE
GENERIC NAME: Co-timoxazole
BRANDNAME: Septran
DESCRIPTION:A combinationof twoantibioticsusedto treatRespiratory, Gastro-intestinal, urinarytract
and skininfection
CATEGORY: Folicacidinhibitor/sulphonamide
CONTENT:Tab 80/400mg: Trimethoprim80mg,sulfametoxazole 400mg
INDICATION:Respiratory, Gastro-intestinal, urinarytractandskininfection
PREGNANCY:Contraindicated
LACTATION:Contraindicated
PRECAUTION:elderly,renalimpairment,severe allergyorasthma, folate deficiency.Performregular
hematological testregularlyduringlongtermtherapy.maintain urineoutput
CONTRAINDICATION:Neonates,severe renal orhepaticinsuffiencyblooddyscrasias
INTERACTION:folate inhibitors,anti coagulants,anticonvulsants,hypoglycaemics,cyclosporine
,procainamide ,thiazide,amantadine,digoxin,pyrimethamine.
ADVERSEEFFECTS: nausea,vomiting,skin rashes,blood dyscrrasias,folatedeficiency,liverenzyme
changes,Steven Johnson’s syndrome,dermatitis,convulsions,ataxia
PHARMACODYNAMICS:Sulfamethoxazole inhibitsbacterial synthesisof dihydrofolicacidbycompeting
withPABA.Trimethoprimblocksproductionof tetrahydrofolicacidbyinhibitingthe enzyme
dihydrofolatereductase.Thiscombinationblocks2consecutive stepsinbacterial biosynthesisof
essential nucleicacidsandproteinsandisusuallybactericidal
PHARMACOKINETICS:
Absorption:Trimethoprim/sulfamethoxazole israpidlyabsorbedfollowingPOadministration.Tmax is 1
to 4 hr. Steadystate isachievedafter3 days.
Distribution:70%of sulfamethoxazole and44% of trimethoprimisproteinbound.
Trimethoprim/sulfamethoxazoleisdistributedtosputum, vaginal fluid,andmiddleearfluid.
Trimethoprim/sulfamethoxazolepassesthe placental barrierandisexcretedinhumanmilk.
Metabolism:Metabolismof sulfamethoxazole isprimarilybyN 4 -acetylation.The principal metabolites
of trimethoprimare the 1- and 3-oxidesandthe 3- and 4-hydroxyderivatives.The free formsare
consideredtherapeuticallyactive.
Elimination:Serumt½ of sulfamethoxazoleandtrimethoprimis10 hr.and 8 to 10 hr.,respectively.
Trimethoprim/sulfamethoxazoleisprimarilyeliminatedbykidneysthroughglomerularfiltrationand
