INTRODUCTION Sulfonamides were the first effective, synthetic antibacterial agents to be used systemically in man. They were introduced by Domagk in 1935 and in the next few years several of them were synthesized and widely used. Currently their role in therapeutics is limited because of their toxicity, development of resistance availability of safer drugs. CLASSIFICATION Short acting: Sulfisoxazole, Sulfadiazine Intermediate acting: Sulfamethoxazole Long-acting: Sulfamethoxypyridazine, sulfadoxine Poorly absorbed: Sulfasalazine Topical: Sulfacetamide, mefedine Silver sulfadiazine. ANTIBACTERIAL SPECTRUM It is wide spectrum antibiotic. It inhibits many gram positive and some gram negative bacteria including streptococci, H. influenza, Norcardia, E. coli, proteus, V. cholerae, some stains of staphylococci, gonococci, memingococci and pneumococci. They are also effective against Chlamydia, plasmodium falciparum and toxoplasma gondii. MECHANISM OF ACTION PABA (Para-aminobenzoic acid) Folic acid synthesis DIHYDROFOLIC ACID Bacteria synthesize their own folic acid from PABA with the help of the enzyme folic acid synthetase. Sulfonamides are structurally similar to PABA and competitively inhibiting the enzymes folic acid synthetase. They inhibit the enzyme folic acid synthase so folic acid is not synthesized (which is essential bacterial growth). PHARMACOKINETICS Sulfonamides are well absorbed, extensively bound to plasma proteins and are well distributed to all tissues. They are metabolized in the liver and excreted in urine. They can cross placental barriers. COMMON USES SYSTEMIC USES : sulfamethoxazole is used in combination with cotrimoxazolein many bacterial infections. It is the drug of choice in pneumocystitis in AIDS patient. Treatment of nocardiosis, toxoplasmosis, ulcerative colitis and rheumatoid arthritis. TOPICAL USES: ocular sulfacetamide sodium is used in trachoma/inclusion conjuctivitis. Topical silver sulfadiazine is used for preventing infection on burn surfaces. Mefinide is active in the presence of pus and against pseudomonas, clostridia which are not inhibited by topical sulfonamides. USES Because of the development of resistance and availability of better antimicrobials, which are more effective and less toxic, these are not commonly used now except in a few cases: UTI NOCARDIOSIS TOXOPLASMOSIS TRACHOMA AND INCLUSION CONJUCTIVITIS MALARIA TOPICAL ULCERATIVE COLLITIS Contraindication & Precautions: Children younger than 2yrs, Pregnant and breast feeding mother, Renal and hepatic diseases, Hypersensitivity to sulphonamides drug. Adverse effect: Fever, Rash, Nausea/vomiting, Aplastic Anemia. DRUG INTERACTIONS Sulphonamides can increasing the blood thinning effect of warfarin, possibly leading to abnormal bleeding. Increases blood level of potassium may occur when Sulfamethoxazole trimethoprim is combined with ACE inhibitors. Su

2. SULFONAMIDES

3. INTRODUCTION
 Sulfonamides were the first effective, synthetic
antibacterial agents to be used systemically in man.
 They were introduced by Domagk in 1935 and in
the next few years several of them were
synthesized and widely used. Currently their role in
therapeutics is limited because of their toxicity,
development of resistance availability of safer
drugs.

4. CLASSIFICATION
1. Short acting: Sulfisoxazole, Sulfadiazine
2. Intermediate acting: Sulfamethoxazole
3. Long-acting: Sulfamethoxypyridazine, sulfadoxine
4. Poorly absorbed: Sulfasalazine
5. Topical: Sulfacetamide, mefedine
Silver sulfadiazine.

5. S.
no.
Drugs Doses
1. Sulfadiazime 3g followed by 1-1.5gm
every 6hrs.
2. Sulfisoxazole 4-6gm /per day in divided
doses
3. Sulfasalazine 1-2gm 4time in a day or
2gm/day in divided doses.
4. Sulmethazaz
ole
160 – 800mg every 12 hrs.
5. Sulfamethazi
ne
3-6gm every 6hrs

6. ANTIBACTERIAL SPECTRUM
 It is wide spectrum antibiotic.
 It inhibits many gram positive and some gram
negative bacteria including streptococci, H.
influenza, Norcardia, E. coli, proteus, V. cholerae,
some stains of staphylococci, gonococci,
memingococci and pneumococci.
 They are also effective against Chlamydia,
plasmodium falciparum and toxoplasma gondii.

7. MECHANISM OF ACTION
PABA (Para-aminobenzoic acid)
Folic acid synthesis
DIHYDROFOLIC ACID
Bacteria synthesize their own folic acid from PABA with the
help of the enzyme folic acid synthetase. Sulfonamides are
structurally similar to PABA and competitively inhibiting
the enzymes folic acid synthetase.
 They inhibit the enzyme folic acid synthase so folic acid is
not synthesized (which is essential bacterial growth).
SULFONAMIDES

8. PHARMACOKINETICS
 Sulfonamides are well absorbed, extensively bound to
plasma proteins and are well distributed to all tissues.
 They are metabolized in the liver and excreted in urine.
 They can cross placental barriers.

9. COMMON USES
 SYSTEMIC USES :
sulfamethoxazole is used
in combination with
cotrimoxazolein many
bacterial infections.
 It is the drug of choice in
pneumocystitis in AIDS
patient.
 Treatment of nocardiosis,
toxoplasmosis, ulcerative
colitis and rheumatoid
arthritis.
 TOPICAL USES: ocular
sulfacetamide sodium is
used in trachoma/inclusion
conjuctivitis.
 Topical silver sulfadiazine
is used for preventing
infection on burn surfaces.
 Mefinide is active in the
presence of pus and against
pseudomonas, clostridia
which are not inhibited by
topical sulfonamides.

10. USES
 Because of the development of resistance and
availability of better antimicrobials, which are more
effective and less toxic, these are not commonly used
now except in a few cases:
 UTI
 NOCARDIOSIS
 TOXOPLASMOSIS
 TRACHOMAAND INCLUSION CONJUCTIVITIS
 MALARIA
 TOPICAL
 ULCERATIVE COLLITIS

11.  Contraindication & Precautions: Children
younger than 2yrs, Pregnant and breast
feeding mother, Renal and hepatic diseases,
Hypersensitivity to sulphonamides drug.
 Adverse effect: Fever, Rash,
Nausea/vomiting, Aplastic Anemia.

12. DRUG INTERACTIONS
1. Sulphonamides can increasing the blood
thinning effect of warfarin, possibly leading to
abnormal bleeding.
2. Increases blood level of potassium may occur
when Sulfamethoxazole trimethoprim is
combined with ACE inhibitors.
3. Sulphonamides may increase the
effectiveness of oral hypoglycemics drugs.
4. Sulphonamides may increase the
effectiveness of hormonal contraceptives
drugs.

13. NURSING IMPLICATIONS
 Patient should be advised to take plenty of water.
 These drugs should be avoided during pregnancy.
 The renal functions should be regularly monitored.
 Patient should be advised to avoid direct sun exposure.
 Patient should be regularly enquired about any side
effects.