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Flashcards in Ranitidine Deck (17)
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1
Q

What is Ranitidine?

A

non-imadazole blocker of Histamine 2 receptors which mediate gastric secretion

2
Q

What class of drugs does Ranitidine belong to?

A

Hyperacidicty, reflux and ulcers

3
Q

What are examples of other drugs in the same class as Ranitidine?

A
Cimetidine
Simethicone
Bismuth trioxide
alginates
Famotidine
4
Q

What is Ranitidine indicated for?

A
  • benign peptic ulceration
  • chronic episodic dyspepsia
  • treatment of NSAID-associated ulceration
  • prevention of NSAID-associated duodenal ulcers
  • GORD
  • stress ulcer prophylaxis
  • prevention of GI haemorrhage when ulcers present
  • prophylaxis of acid aspiration in srugery and labour
5
Q

What is the mechanism of action of Ranitidine?

A
  • Inhibits Histamine-2 receptors on parietal cells and suppresses acid secretion by

1) blocking ECL cells released by histamine from binding on parietal H2 receptors
2) other substances promoting acid secretion (gastrin and acetylcholine) have less effect on parietal cells when H2 receptors are blocked

6
Q

What is the role of ranitidine in therapy?

A

second line for patients with GORD (mild symptoms who have not responded to a 4-6 week trial with PPI)

or can be used adjunctive to PPI following discussion with specialist e.g. in patients with nocturnal symptoms unimproved following morning dosing with a PPI may benefit from 300mg ranitidine at night for up to 8 weeks

7
Q

What is the dose of Ranitidine given for benign peptic ulceration?

A

adult: 150mg bd or 300mg nocte for 4-8 weeks

8
Q

What is the dose of Ranitidine given for chronic episodic dyspepsia?

A

150mg bd, or 300mg nocte up to 6 weeks

9
Q

What is the dose of Ranitidine given for NSAID-assoc ulceration?

A

150mg bd or 300mg nocte for up to 8 weeks

in duodenal ulcer: 300mg can be given bd for 4 weeks for a higher healing rate

maintenance = 150mg nocte.

10
Q

What is the dose of Ranitidine given for prophylaxis of NSAID-assoc duodenal ulceration?

A

up to 150mg bd

11
Q

What is the dose of Ranitidine given for GORD?

A

Adult 150mg bd or 300mg up to 8 weeks

If mod-severe: 600mg OD in 2-4 divided doses for up to 12 weeks.

Long term treatment of healed GORD = 150mg bd

12
Q

What is the dose of Ranitidine given for prevention of GI haemorrhage when ulcers are present and in stress ulcer prophylaxis?

A

Adult: once injection has stopped, 150mg BD

13
Q

What are the relevant PD/PK parameters with Ranitidine use?

A

PK:

approx 50% bioavailability orally

15% bound to proteins

hepatically metabolised

Primarily excreted in urine

half life: 2.8-3.1 hours

14
Q

What are the cautions associated with Ranitidine use?

A
  • may mask symptoms of gastric cancer
  • cardiac rhythm disturbances (bradycardia with rapid IV admin)
  • if renal impairment, use half normal dose if eGFR<50ml/min
  • pregnancy B1: manufacturer advised to avoid unless essential, compatible with breastfeeding
15
Q

What are the adverse effects with Ranitidine use?

A
  • diarrhoea,
  • headache, dizziness
  • rash (erythema multiforme and toxic epidermal necrolysis)
  • blurred vision
16
Q

What are the relevant drug interacts with Ranitidine use?

A

Avoid concurrent use with histamine as Ranitidine blocks the effects of histamine

  • markedly reduces ketoconazole exposure
17
Q

What are the alarm bells with Ranitidine use?

A

report new and worsening symptoms to the doctor

may have elevated LFTs, hepatitis, jaundice,

May mask gastric cancer symptoms - rule out before initiating treatment