Paper II — 2023 July (Supplementary) (2010 Scheme) — Q6

Paper II

2023 July (Supplementary) (2010 Scheme)

Question

Cotrimoxazole

Q63 marksShort Notes★✓

Answer

Combination of Sulfamethoxazole + Trimethoprim (5:1), causing sequential blockade of bacterial folate synthesis. MOA: Sulfamethoxazole competitively inhibits dihydropteroate synthase; Trimethoprim inhibits dihydrofolate reductase — synergistic bactericidal action.

Uses

• Urinary tract infection
• Respiratory tract infections
• Pneumocystis jirovecii pneumonia — treatment and prophylaxis in HIV
• Typhoid fever
• Traveler’s diarrhea

Adverse effects

• Hypersensitivity, including Stevens-Johnson syndrome
• Hemolysis in G6PD deficiency
• Kernicterus in neonates
• Megaloblastic anemia (folate antagonism)
• Crystalluria

Related Concepts

1. 1Sulfonamides and Cotrimoxazole

Other Years Asked

1. 1Cotrimoxazole2022 May (Supplementary) (2010 Scheme)Short Note · 3 marks
2. 2Cotrimoxazole2021 February (Supplementary) (2010 Scheme)Short Note · 3 marks
3. 3Trimethoprim and Sulfamethoxazole as a combination2024 August (Supplementary) (2010 Scheme)Short Answer · 1 mark
4. 4Mechanism of action of cotrimoxazole2016 February (2010 Scheme)Short Answer · 1 mark
5. 5Treatment of pneumocystis carnii2015 February (2010 Scheme)Short Answer · 1 mark
6. 6Combination of Trimethoprim and Sulfamethoxazole.2025 March (Supplementary) (2010 Scheme)Short Answer · 1 mark
7. 7Mechanism of action of co-trimoxazole.2015 September (Supplementary) (2010 Scheme)Short Answer · 1 mark
8. 8Drugs for pneumocystis carini infection2022 February (2019 Scheme)Short Answer · 0.2 marks