Chemistry of motility drugs

Question 1

Acute diarrhoea adsorbent & bulk forming

Answer 1

Kaolin

Question 2

Anti-motility drugs

Answer 2

Diphenoxylate + atropine (co-phenotrope)
Codeine phosphate
Morphine (with kaolin)
Loperamide
Racecedotril

Question 3

Opioid receptor drugs mechanism

Answer 3

Decrease ACh release decreasing peristaltic activity
Decreases cellular cAMP reducing levels of water and electrolytes
Prodrugs give rise to thiorphan
Thiorphans in stomach creates disulphurides

Question 4

Codeine and Morphine

Answer 4

Codeine more lipophilic

pKa 9 - tertiary amine

tertiary amines can make phosphate salts

Question 5

Loperamide

Answer 5

Non selective calcium channel blocking
Basic drug
pKa of 8.6
Log P 4.5

Question 6

Constipation drugs

Answer 6

Linaclotide
Lubiprostone

Large molecules

Question 7

Linaclotide

Answer 7

Increase water electrolyte secretion
Cyclic peptide
Guanylate cyclase activator
Polar molecule

Question 8

Prostones

Answer 8

CIC-2 calcium channel activator
Increase water electrolyte secretion
Given as capsule