Opath 1 - Block 2 - Chiu - Antimetabolites

Front 1

Sulfonamides

Back 1

- All structurally related to PABA
- Compete for enzyme dihydropteroate synthetase (DHPS), preventing synthesis of bacterial folic acid
- deprives cell of purine, pyrimidine, and amino acid synthesis

Front 2

Antibacterial spectrum of sulfonamides

Back 2

- enterobacteriaceae
- chlamydia
- nocardia
- toxoplasmosis

Front 3

Administration of sulfonamides

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- well absorbed orally
- Sulfasalazine - oral or rectal. Treatment of Crohn's or Ulcerative Colitis. IV available.

Front 4

Therapeutic uses of sulfonamides

Back 4

- Urinary tract infections (+ Trimethoprim). E.coli.
- Nocardiosis - pneumonia and brain abscess in immunocompromised pts.

Front 5

Adverse reactions of sulfonamides

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- Crystalluria - need adequate hydration and alkalination of urine
- Hypersensitivity - rash, angeioedema, Steven's-Johnson
- Hemopoetic
- Kernicterus - in infants. Increased levels of BILIRUBIN that gets into the CNS. Brain damage.

Front 6

Drug interactions of sulfonamides

Back 6

- Displace drugs from binding sites on serum albumin to potentiate effects
- Form complexes with formaldehyde - Do not give to patients on methenamine

Front 7

Trimethoprim

Back 7

- Potent inhibitor of bacterial dihydrofolate reductase
- Often combined with sulfonamides
- folate coenzymes bcome unavailable for purine, pyrimidine, and amino acid synthesis

Front 8

Antibacterial spectrum of trimethoprim

Back 8

- 20-50 times more potent than sulfonamide
- Used alone or in combination

Front 9

Co-Trimoxazole

Back 9

Sulfamethoxazole + trimethoprim
Inhibits both steps of PABA+pteridine metabolic pathway
Broad spectrum
Less frequent resistance

Front 10

Therapeutic uses of Co-Trimoxazole

Back 10

- PCP
- respiratory infections
- PROSTATE and UTIs - CHRONIC AND RECURRENT
- genital infections
- GI infections

Front 11

Adverse effects of Co-Trimoxazole

Back 11

- GI disturbances
- hematological - megaloblastic anemia, leukopenia, thrombocytopenia
- folate deficiency - megaloblastic anemia, leukopenia, granulocytopenia
- fever, rash, diarrhea