CIMETIDINE oral

Therapeutic action

• Antiulcer agent (histamine H2-receptor antagonist)

Indications

• Prophylaxis of acid pulmonary aspiration syndrome in anaesthesia:
  • in patients with a full stomach (emergency caesarean section, etc.)
  • when a difficult intubation is expected

Forms and strengths

• 200 mg effervescent tablet
  Also comes 800 mg effervescent tablet.

Dosage and duration

• Adult: 200 to 400 mg single dose, if possible one hour before anaesthetic induction

Contra-indications, adverse effects, precautions

• May cause: diarrhoea, headache, dizziness, skin rash, fever.
• Do not administer with an antacid (aluminium hydroxide, etc.).

Remarks

• Effervescent cimetidine can be replaced by effervescent ranitidine, another H2-receptor antagonist, as a single dose of 150 mg.
• The onset of acid inhibition with cimetidine non-effervescent tablets (200 mg, 400 mg and 800 mg film coated tablets) or ranitidine non-effervescent tablets (150 mg and 300 mg film coated tablets) occurs 30 minutes after administration. The effervescent tablets containing sodium citrate have a more rapid onset of action, and can thus be used for emergency surgery.
• Omeprazole, another antiulcer agent (proton pump inhibitor), is not compatible with emergency situations as it must be administered at least 4 hours before surgery.
• Cimetidine in film coated tablets is also used in the treatment of gastro-oesophageal reflux and peptic ulcer. Use by preference ranitidine or omeprazole for these indications.

Storage