Sulphonamides

Question 1

What is first chemotherapeutic agents used systemically ?

Answer 1

Sulphonamides

Question 2

Their use declined after

Answer 2

Discovery of penicillins and other antibiotics and development of resistance , now use is very restricted

Question 3

Chemically ?

Answer 3

Are derivatives of sulphanilamide ( which contains nitrogen and sulphur in its structure )

Question 4

Mode of action ?

Answer 4

Sulphonamides are structural analogs and competitive antagonists of para- amino Benzoic acid( PABA) they prevent normal bacterial utilization of PABA for synthesis of Folic acid ,sensitive bacteria is that which can not utilize pre formed folic acid them and is not synthesized

Question 5

Anti bacterial spectrum ?

Answer 5

-streptococcus pyogenes 
Haemophilus influenza 
Actinomyces 
Escheria coli 
Streptococcus preumonia
Nocardia 
Chalmydia trachomatis 
Neisseria meniningitidis

Question 6

Pharmacokinetics ?

Answer 6

Are rapidly absorbed ( except those acting locally on the bowel ) from GIT ,approximiately 70-100% of the dose is absorbed.major site of absorption is small intestine - bound (by varying degree to the plasma proteins ) Distributed to all body tissues.
Metabolized in liver to inactive metabolites
Excreted partly unchanged and partly as metabolites by the urinary system .

Question 7

Sulphonamides which are still in use include ?

Answer 7

Sulphamethoxazole 
Sulphadiazine 
Sulphadoxine 
Sulphacetamide
Sulphathiazole

Question 8

Sulphamethoxazole ( Gantanol)?

Answer 8

Is along acting sulphanomide .administered orally for both systemic and urinary tract infections , commonly used in combination with trimethoprim ( co-trimoxazole -septrin ) to potentiale the antibacterial effect .

Question 9

Dose of sulphamethoxazole?

Answer 9

2tablets (400 mg sulphamethazole +50 mg trimthoprim ) every 12 hours for at least five daily
Co- trimoxazole is commonly used in treatment of all systemic infections , but is specifically used for UTI and Typhoid and Toxoplasmosis
(Combined with pyrimethamine )

Question 10

Sulphathiazole ?

Answer 10

This sulphonamide is not absorbed by GIT so its action is local ,used for local treatment of GIT infection

Question 11

Sulphadiazine?

Answer 11

Rapidaly absorbed when given orally, partially metabolized in liver and is excreted to Bacterial Meningitis because it can cross Blood Brain Barrier BBB efficiently, usually adminstered parentrally
Dose:60 mg/k body every 4Hours.

Question 12

Sulphadoxine?

Answer 12

Is along acting sulphonamide, used in comination with pyrimethamine ( Daraprim) (500 mg sulphadoxine +25 mg pyrimethamine - fansidar ) for treatment of malaria
Dose:- a single dose of 3 tablets

Question 13

Sulphacetamide (isoptocetamide )?

Answer 13

A short acting sulphonamide used locally in eye infections especially chlamydia .formulated in sodium salt form ,as eye drops of 20%&30% concentration