Antacids

Question 1

Name the 2 indications for the use of Alginates and antacids.

Answer 1

1) GORD: for symptomatic relief of heartburn.

2) Dyspepsia: for short term relief of indigestion.

Question 2

Give the P drugs classed as antacids/ alginates.

Answer 2

1) Magnesium trisilicate
2) Aluminium/magnesium mixtures (Maalox)
3) Alginates

Question 3

What do alginates do?

Answer 3

1) When taken in combination with an antacid they increase the viscosity of the stomach contents and can protect the oesophageal mucosa from reflux by preventing reflux.
2) They form a viscous gel (‘raft’) that floats on the surface of the stomach contents, thereby reducing symptoms of reflux by separating the gastric contents from the GOJ.
3) Some evidence suggests that they inhibit pepsin production.

Question 4

How do antacids work?

Answer 4

They work by buffering stomach acids.

Question 5

How are alginates and antacids normally taken?

Answer 5

Often as preparations containing an alginate with one or more antacids (sodium bicarbonate, calcium carbonate, magnesium or aluminium salts).

Question 6

1) What side effect do magnesium salts cause?

2) What side effect do aluminium salts cause?

Answer 6

1) Diarrhoea

2) Constipation

Question 7

1) Why should alginates not be given in combination with thickened milk preparations?
2) When should sodium and potassium containing compounds be used with caution?
3) Why might you need to use caution when using antacids and alginates in patients with diabetes?

Answer 7

1) As this can lead to excessively thick stomach contents which can cause bloating and abdominal discomfort.
2) In patients with fluid overload and hyperkalaemia (for example, renal failure).
3) Some preparations contain sucrose which can worsen hyperglycaemia in patients with DM.

Question 8

1) How do alginates reduce absorption of other drugs?
2) Why should antacids be taken at different times to other drugs?
3) Name 2 drugs that antacids increase excretion of.

Answer 8

1) Divalent cations in compound alginates can bind to other drugs and reduce their absorption.
2) Because they can reduce serum concentrations of many drugs.
3) Aspirin and lithium.

Question 9

Name 5 drug types that antacids can reduce serum concentrations of.

Answer 9

1) ACE inhibitors.
2) Some antibiotics (cephalosporins, ciprofloxacin, tetracyclines)
3) Bisphosphonates
4) Digoxin
5) Levothyroxine
6) PPIs

Question 10

Give 2 brand names of alginates.

Answer 10

Gaviscon and Peptac.