Antacids

Question 1

Example of an antacid

Answer 1

Gaviscon

Question 2

How do antacids work?

Answer 2

Often taken as a compound with an alginate.

Work by buffering stomach acid. Alginates act to increase the viscosity of stomach contents which reduces the reflux of the stomach acid into the oesophagus. After reacting with stomach acid they form a floating ‘raft’, which separates the gastric contents from the gastro-oesophageal junction to prevent mucosal damage.

Antacids alone can be used for short term relief of dyspepsia (indigestion)

Question 3

Indications of antacids

Answer 3

GORD: symptomatic relief of heart burn
Dyspepsia: for short term relief of indigestion

Question 4

Contra-indications of antacids

Answer 4

Compound alginates are safe in pregnancy. Paediatric formulations are safe for use in infants but shouldn’t be given in combination with thickened milk preparations they can lead to excessively thick stomach acid contents that causes bloating and abdominal discomfort.
Sodium and potassium containing preparations should be used with caution in patient with hyperkalaemia (e.g. renal failure).
Some preparations contain sucrose, which can worsen hyperglycaemia in people with diabetes mellitus.

Question 5

Side effects of antacids

Answer 5

Magnesium salts can cause diarrhoea, whereas aluminium salts can cause constipation.

Question 6

Possible interactions of antacids

Answer 6

The divalent cations in alginates can bind to other drugs, reducing their absorption.
Antacids can reduce serum concentrations of many drugs, so the doses should be taken at different times. This applies to ACE inhibitors some antibiotics (cephalosporins, ciprofloxacin and tetracyclines), bisphonates, digoxin, levotyroxine and PPIs.
By increasing the alkalinity of urine, antacids can increase the excretion of aspirin and lithium.

Question 7

Elimination of antacids

Answer 7

Renal

Question 8

Patient information needed for antacids

Answer 8

Available as chewable tablets or oral suspension. Should be taken following meals, before bedtime and/or when symptoms occur. Leave a gap of 2 hours before taking any more of the same or other medicines as they may interact.
For infants, oral powder can be mixed with feeds or water.
Should relieve symptoms within 20 minutes and for several hours afterwards.
This is a temporary solution. Lifestyle changes can help to reduce reflux, sick as eating smaller means more often, avoiding food and drink triggers, stopping smoking.
Warn patients to return if symptoms persist.