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Flashcards in Drugs and the GI tract Deck (7)
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1
Q

What are the 3 upper GI tract disorders?

A

Indigestion -
- discomfort/pain in stomach, bloating, burping, nausea, heartburn
- caused by pregnancy, ulcers, over-eating, anxiety
Gastro-oesophageal Reflux Disorders (GORD) -
- heart burn, sour mouth
- caused by overeating, pregnancy, certain drugs, ulcers, stress/anxiety
Ulcers -
- pain, bleeding
- caused by bacterial infections (H. pylori), NSAIDS, smoking, anxiety/stress

2
Q

Antacids

A

Act locally to neutralise acid in the stomach
As a result of the pH being less acidic this also decreases pepsin activity
Contain calcium, aluminium, and magnesium salts (Rennies and Maalox)
eg. Simeticone (Asilone) alters surface tension of small bubbles of gas to allow formation of large bubbles which can be got rid of
eg. Alginates (Gaviscon) reacts with gastric juices to form a raft that floats on top and protects oesophagus from stomach contents

3
Q

Drugs influencing gut motility

A

Hyoscine Butyl Bromide (Buscapan) -
- antispasmodic that acts on the intestine and relaxes smooth muscle to reduce gut motility
Meberverine Hydrochloride (Colofac) -
- same role as Buscapan
Side effects: constipation, dry mouth
Domperidone (Motilium) -
- gut motility stimulant (action in stomach sphincters)
- dopamine receptor antagonist that increases peristalsis, relaxes the pyloric sphincter (increasing gastric emptying) and increase oesophageal sphincter tone

4
Q

Ulcer-healing drugs

A

Ranitidine (Zantac) -
- H2 receptor antagonist that blocks the H2 receptors on the parietal cells in the stomach to reduce acid production by blocking histamine receptors that produce H+
-don’t take at same time as antacids as won’t work
- interfere with WARFARIN, THEOPHYLLINE
Omeprazole (Losec) -
- protein-pump inhibitor
- when the pH of the stomach is acidic it will form 2 reactive molecules
- it will permanently bind to a protein pump and the protein pump will never pump acid again (HCl)
-give 30 mins before food
- interfere with DIAZEPAM, PHENYTON, THEOPHYLLINE

5
Q

Ulcer-healing drugs cont.

A

Misoprostol -
- synthetic prostaglandin E1
- prostaglandins protect the stomach by preventing acid production and stimulating mucus release
- do not give to pregnant women as can cause premature labour/spontaneous abortion
Side effects: diarrhoea, abdominal pain
Treatment for H. pylori -
- requires 2 antibiotics and a protein pump inhibitor or a H2 receptor antagonist to reduce acid secretion
eg’s.of antibiotics used.. Clarithromycin, Amoxicillin, Metronidazole, Tetracycline

6
Q

Drugs used in acute diarrhoea

A

Oral rehydration therapy -
-first line treatment containing glucose, water and electrolytes
- stimulates the absorption of water and electrolytes
eg. Dioralyte, Electrolade
Loperamide (Imodium) -
- anti-diarrhoeal that acts on the small and large intestine
- they are related to opioids and work by decreasing peristalsis in the small and large intestine
- also decrease explosive contractions of the colon
- side effects: nausea and vomiting, increased HR

7
Q

Laxative drugs

A

Ispaghula Husk (Fybogel) -
- bulk forming laxative that increases faecal mass to stimulate peristalsis
- takes a few days to work
Dantron and Senna (Sennokot) -
- stimulant laxatives that increase peristalsis to move the stool through the large intestine
- take at night so effective in the morning
Lactulose and Macrogol (Movicol) -
- osmotic laxatives that contain large sugars/ magnesium and sodium salts
- poorly soluble, not absorbed and they work by drawing water into the gut making stools softer and easier to pass
- take a couple of days to work