Drugs

Question 1

What Class of Drug is Tamsulosin? What is its Mechanism of Action?

Answer 1

• Alpha-adrenergic Antagonist
• Smooth muscle relaxant of alpha 1 receptors of bladder neck, urethra and prostate.
• Facilitates urinary flow

Question 2

What is Tamsulosin used to treat?

Answer 2

Altered Voiding - Urinary Retention + Benign Prostatic Hyperplasia (BPH)

Question 3

What drug Class does Oxbutynin belong to? What is its Mechanism of action?

Answer 3

• Antimuscarinic
• Blockade of muscarnic acetylcholine receptions leading to relaxation of bladder detrusor muscle to promote urinary storage.
• Selective antagonist of M1 and M2 Receptors

Question 4

What is Oxybutynin used to treat?

Answer 4

• Urinary Incontinence

- Overactive bladder syndrome

Question 5

What is an Anti-muscarinic? Give an example.

Answer 5

• Drugs used to relax the detrusor muscle of bladder to promote storage of urine
• Oxybutynin

Question 6

What Drugs are used for treating dyspepsia, GORD, Peptic ulcers?

Answer 6

• Aluminium Hydroxide + Magnesium Hydroxide
• Sodium alginate with Sodium Bicarbonate + Calcium Carbonate
• Famotidine (H2 Receptor Blocker)
• Omeprazole/Lansoprazole (Proton Pump Inhibitors

Question 7

What Is the Mechanism of Action for Famotidine?

Answer 7

• Histamine (H2) Receptor Antagonist
• Act competitively w/histamine at receptor on Gastric Parietal Cells
• Reduces basal acid secretion + Pepsin Production
• Prevents increase in secretion that occurs in response to several secretory stimuli

Question 8

Give an Example of a Histamine Receptor Antagonist

Answer 8

Famotidine

Question 9

What are side effects of the Histamine Receptor Antagonist, Famotidine?

Answer 9

• Diarrhoea
• Headache, dizziness, Tiredness
• Rash

Question 10

What is Omeprazole and Lansoprazole? Explain their Mechanisms of Action?

Answer 10

• Proton Pump Inhibitors
• Inhibits the H+/K+-ATPase almost completely and irreversibly
• Decrease both Basal and stimulated acid secretion
• More effective than H2 Receptor Antagonists/Famotidine
• Accumulate in secretory canaliculi of Parietal cells where activated

Question 11

What are Purgatives?

Answer 11

Laxatives used to treat Constipation

Question 12

What are the Classes of Purgative Drugs?

Answer 12

• Bulk Laxative Class
• Osmotic Laxative Class
• Faecal Softener Class
• Stimulant-Purgative Class

Question 13

What is Methylcellulose? What is its mechanism of action?

Answer 13

• A bulk class laxative
• A polysaccharide polymer, is not broken down by normal process of digestion proceeds to large intestine where it exerts hydrophilic action, causing retention of water in gut lumen, expands and softens faeces
• Proliferation of colonic bacteria which further increases faecal bulk
• Bulkier stool drives colonic distension which stimulates intestinal motility

Question 14

Give an example of a bulk laxative class

Answer 14

Methylcellulose

Ispaghula Husk

Question 15

What are Bulk Laxatives used to treat? Why?

Answer 15

Constipation and IBS

Retain water in themselves in the GI lumen, softens and increases faecal bulk and promotes increased motility

Question 16

What are Osmotic laxatives? Give examples

Answer 16

Drugs which promote movement of fluid across the wall into the GI lumen, accelerates transit time + Causes colonic distension, stimulating transit and purgation

• Saline Purgatives - Bowel prep
• Macrogol
• Lactulose

Question 17

What are Stimulant Purgatives. What are their mechanisms of action?

Answer 17

• Senna, Bisacodyl
• Stimulates increased intestinal motility Including Stimulation of local reflexes through myenteric nerve plexuses in gut. Increases water and electrolyte transfer into lower gut