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, including emergency caesarean section.
• When a difficult intubation is expected.

Forms and strengths

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

Dose 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, and fever.
• Do not administer with an antacid such as aluminium hydroxide.
• 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 non-effervescent cimetidine or ranitidine tablets is around 30 minutes after administration. Effervescent tablets containing sodium citrate have a more rapid onset of action and can be used for emergency surgery.
• Omeprazole is not compatible with emergency situations because it must be administered at least 4 hours before surgery.