Therapeutic options and referral Flashcards
What are antacids made of and what are some of the brand names?
Antacids consists of magnesium, aluminium, sodium and calcium salts
Brand names include:
Rennies, Tums and Settlers
How do antacids work?
Antacid salts bind to acid within the stomach causing a neutralisation reactions causing release of CO2 (burp).
Alkalinisation can increase the LOS sphincter pressure (reducing GORD) and induce mucosal protection by stimulation of prostaglandin synthesis (allowing ulcer healing).
What are some of the key counselling points for antacids use?
Liquids work more effectively, increased surface area
Tablets should be chewed
Take one after a meal due to reduced gastric emptying (3 hours effect compared to 1hour if not taken after a meal)
Short term use
Not be used as a preventative
Why are antacids limited to short term use?
Presence of antacids causes an increase in pH within the stomach. Acid production increases with pH and therefore can cause acid rebound.
What are some of the indications of antacids?
Functional dyspepsia
Gastric and duodenal ulcers
Oesophagitis
GORD
What are some of the main side effects of antacids?
Aluminium:
Constipation
Osteoporosis (binding to phosphate in the gut)
Neurotoxicity (absorbed)
Magnesium:
Diarrhoea
All can cause acid rebound, therefore only short-term use
When should excessive sodium based antacids be avoided?
In hypertensive / cardiac patients
Are antacids safe for use in pregnancy?
Yes but mindful of sodium content
What drug interactions should you be mindful of with antacid use?
Antacids will damage the enteric coating of some drugs
Binding with tetracyclines and iron based drugs
How do alginates work?
Alginates are formulated with an antacid and once they reach the acidic pH within the stomach they form a high pH viscous mass, essentially a ‘raft’ which traps air and bubbles (due to the antacid reaction causing the release of carbon dioxide which is trapped within the raft).
This rafts sits on top of the stomach and protects the oesophageal mucosa from reflux.
What is the purpose of Simethicone (Dimeticone)?
It is an anti-foaming agent which reduces the surface tension of intra-gastric air bubbles, breaks down the bubble and lets smaller bubbles escape (reducing the feeling of bloatedness).
What are some examples of H2 antagonists?
Cimetidine, Ranotidine, Famotidine, Nizatidine
How do H2 antagonists work?
Compete for H2 receptor binding on parietal cells, preventing activation by histamine and hence acid secretion.
Large stimulus such as a large meal will override these effects.
How does the DOA/onset time compare to that of antacids?
Longer duration of action and time of onset
What are the beneficial outcomes of H2 antagonists on peptic ulcer disease?
High healing rates
However does not affect relapse (has H pylori been eradicated)
What are the beneficial outcomes of H2 antagonists on GORD?
80-90% mild oesophagitis improvement after 12 weeks
Not used for moderate to severe disease
PPI is first line so would only expect use is PPI was not effective
What is the side effect profile like for H2 antagonists?
Only 1-7% experience side effects
What are the associated side effects for some of the H2 antagonists?
Increased prevalence of headache and dizziness in comparison to placebo
Cimetidine - gynaecomastia (swelling of male breast tissue), impaired libido
Nizatidine - abnormal dreams, sweating
Confusion in the elderly
What are the main drug interactions associated with Cimetidine?
Cimetidine is a CYP 450 inhibitor, and therefore drugs that rely on this enzyme for metabolism have increased concentrations in vivo.
Including theophylline, warfarin, phenytoin
Which H2 antagonist can be bought OTC?
Ranitidine (Zantac 75)
What is Ranitidine indicated for?
Symptomatic relief of heartburn, dyspepsia and hyperacidity
What are some counselling points for use of Ranitidine?
Maximum 6 day continuous use before seeking advice from the GP/Pharmacist
OTC- maximum 2 tablets in 24 hours whereas
POM - 150mg twice daily or 300mg at night
How is Ranitidine often used?
Prophylactically before a meal known to induce dyspeptic like symptoms
What are some examples of proton pump inhibitors?
Lansoprazole, Esomeprazole, Pantoprazole, Omeprazole
Why are PPIs enteric coated?
They are acid labile and hence destroyed by contents within the stomach, so are enteric coated to ensure absorption into the small intestine
Why would you co-prescribe an antacid for the first couple of days whilst also taking a PPI?
PPIs take a couple of days to reach full effect and therefore an antacid can provide symptomatic relief almost instantly
How do PPIs work?
Proton pump inhibitors (PPIs) block the gastric H+/K+ -ATPase, inhibiting gastric acid secretion regardless of whether the parietal cell is stimulated
What is the effect of PPIs on gastric acid secretion?
20mg Omeprazole blocks 80% of gastric acid secretion
40mg Omeprazole blocks 100% of gastric acid secretion
Why are PPIs used in preference for the treatment of ulcers?
They heal ulcers more quickly than H2 antagonists, the healing rate is the same after 8 weeks however.
Also superior in the treatment of reflux and GORD.
What are some of the side effects associated with PPIs?
Nausea
Vomiting
Flatulence
Diarrhoea
Epigastric pain
Dry mouth
Headache
Arthralgia
Myalgia
Risk of bacterial overgrowth (due to absence of acid) - increased risk of Helicobacter or Salmonella infection
Rebound acid after prolonged treatment (use lowest dose, as needed)
Should PPIs be taken with food?
No, taking Lansoprazole with food reduces the bioavailability
Which PPI is licensed over the counter?
Esomeprazole
What are some of the counselling points for PPI sale OTC?
Indicated for reflux in over 18s
Should be swallowed whole with plenty of liquid
20mg until symptoms improve then 10mg
When should the OTC sale of a PPI be referred to the GP?
No improvement after 2 weeks
If treatment is required continuously for more than 4 weeks
Patient is over 45 and presents with new or changed symptoms
List other drugs that can be used in the treatment of upper GI conditions.
Metoclopramide and Domperidone
Sucralfate
Bismuth
Misoprostol
How does Metoclopramide and Domperidone work?
Increases gastric emptying and LOS tone
Why is domperidone not used OTC anymore?
Due to CVD risk
How does Sucralfate work?
Polymerizes below pH4 to form a sticky gel
Protective barrier over ulcer (adheres strongly to ulcer)
Physical protection and allows bicarbonate to re-establish pH gradient
How does Bismuth work?
May act similarly to sucralfate
Strong affinity for mucosa, especially in ulcer craters
May blacken teeth and stools
How does Misoprostol work?
Promotes ulcer healing by stimulating protective mechanisms – sometimes used with NSAIDs
What is the main treatment for gastritis, PUD or functional dyspepsia?
- Removal of causative agents
- Dietary changes
- Symptomatic management
- H2 antagonists or Proton pump inhibitors
Undiagnosed upper GI conditions can be treated OTC with care not to mask symptoms of gastric cancer
What is the main treatment for GORD?
Lifestyle and dietary changes
Alginate products or PPIs
DON’T use H2 antagonists first line (only in inadequate response)
Undiagnosed upper GI conditions can be treated OTC with care not to mask symptoms of gastric cancer
When should referrals be made for dyspeptic symptoms?
*Patient over 45 with a new/changed
symptoms of heartburn or dyspepsia
*Child presentations
*Continued nausea and vomiting
* Continuous dyspepsia
* Increasing severity
* Weight loss, loss of appetite, sign of
anaemia
* Pain on exercise - cardiac origin?
* Dysphagia
* Unexplainable pain on swallowing
* Blood in vomit or stools
