Medicines & Supplements A to Z > Gastrocaine


Last updated on 25/07/2021.

Overview   |   Dosage   |    Side Effects   |   Precautions  |   Tips  |   Where To Buy  

GENERIC NAME: Oxethazaine hydrochloride + Aluminium hydroxide + Magnesium hydroxide


CHINESE NAME: 胃舒錠, 鹽酸奧塞沙因 + 氫氧化鋁 + 氫氧化鎂


DRUG CLASS: Gastrointestinal Drugs

SUB CLASS: Antacids, Anesthetics

USED FOR: Gastroesophageal Reflux Disease (GERD)

– 5 mg/ 126 mg/ 100 mg (tablets)
– 2 mg/ml/ 30 mg/ml/ 10 mg/ml (suspension)

What is Gastrocaine for?

Gastrocaine is a combination therapy of Oxethazaine, Aluminium hydroxide and Magnesium hydroxide. Aluminium hydroxide and magnesium hydroxide reduce the acidity of gastric content and relieves heartburn. Oxethazaine is an anesthetic that relieves pain directly.

How to use it?

Gastrocaine is taken orally as tablets or suspension. It should be taken 15 minutes before meals and at bedtime. Shake the suspension bottle before use and drink without diluting it. You may drink a little bit of water if necessary afterwards.

Relief of Gastroesophageal Reflux Disease (GERD)
Child, adult and elderly
Suspension: 10-20 mL 4 times daily.
Tablet: 2-4 tablets 4 times daily.

What are the side effects of Gastrocaine?

Common side effects of Gastrocaine include diarrhoea, constipation and electrolyte imbalance are some of the uncommon side effects.

Who should not take Gastrocaine?

– Patients with impaired kidney function.
– People allergic to Oxethazaine hydrochloride, Aluminium hydroxide, Magnesium hydroxide or any component of the formulation.

Pharmacist Tips:

– Gastrocaine is only a symptomatic relief medication for heartburn. If symptoms recur or exacerbate, seek medical attention.
– If pain radiates to the back, left upper arm or neck, please seek  medical attention immediately.
– Although this medication is not contra-indicated for pregnant women, it is advised to avoid administration of self-purchased drugs.
– Shake the suspension bottle before use and drink without diluting it. You may drink a little bit of water if necessary afterwards.

Common dosing schedule:
Both the suspension and tablet is to be taken 15 minutes before the 3 meals and at bedtime.

Some common medications Gastrocaine may interact with:
– Acidic drugs, e.g. Digoxin, Phenytoin
– Absorption of antibiotics, e.g. Tetracyclines
– Metal supplements, e.g. Iron, Strontium

Please notify your doctor or pharmacist if you are taking the above medication, dosage adjustments might be needed.

Where to buy Gastrocaine in Hong Kong?

In Hong Kong, Gastrocaine is an over-the-counter medicine and can be purchased without a prescription from any pharmacies in Hong Kong. It can also be obtained from doctors. To find a pharmacy near you, refer to the list of pharmacies (“Authorized Sellers of Poisons”) from the Hong Kong Department of Health.

For more information about drug names and ingredients, you can visit Hong Kong’s Drug Office at

Need more information?

For detailed information about the use of Gastrocaine in children, pregnancy and breastfeeding, and for questions about drug interactions, please check with your pharmacist or doctor.

Disclaimer: our goal is to provide you with the most relevant drug information and common dosage for Hong Kong. This information does not constitute medical advice. For specific treatment recommendations and advice, always discuss with your doctor or pharmacist, and follow the instructions included with your specific medicine.