Paper II — 2024 June (Supplementary) (2019 Scheme) — Q5
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Paper II
2024 June (Supplementary) (2019 Scheme) · 100 marks · 180 min
Question
(
(a) Pharmacotherapy of irritable bowel syndrome with the rationale for use.
(
(b) Oral Contraceptive Pills
Q58 marksShort Essays
Answer
a) Pharmacotherapy of irritable bowel syndrome, with rationale
Antispasmodics (Dicyclomine, Mebeverine) — reduce intestinal smooth muscle spasm, relieving cramping abdominal pain, the predominant symptom in many patients.
Bulk-forming/osmotic laxatives (Ispaghula, Lactulose) — for constipation-predominant IBS, normalizing stool bulk and transit without the harsh stimulant action that could worsen cramping.
Loperamide — for diarrhea-predominant IBS, reduces motility and increases water absorption via opioid-receptor agonism in the gut.
Low-dose tricyclic antidepressants (Amitriptyline) — modulate visceral pain perception at doses well below their antidepressant range, reducing abdominal pain/discomfort.
5-HT3 antagonists (Alosetron) — for severe diarrhea-predominant IBS refractory to other measures, reducing visceral hypersensitivity and colonic transit.
Rationale is symptom-directed, since IBS has no single unifying pathology — therapy targets the predominant symptom pattern (pain, constipation, or diarrhea) in each individual patient rather than a single underlying mechanism.
b) Oral Contraceptive Pills
Combined OCPs contain an estrogen and a progestin. Mechanism: estrogen suppresses FSH (preventing follicular development), progesterone suppresses the LH surge (preventing ovulation), and progesterone additionally thickens cervical mucus and produces an endometrium unfavorable to implantation. Uses: contraception, menstrual cycle regulation, dysmenorrhea, acne. Adverse effects: thromboembolism, breakthrough bleeding, headache, weight gain.
