4.1. Therapeutic indications

1. For the relief of the symptoms of dyspepsia, heartburn and indigestion.

2. As an external lotion for relief of the symptoms of insect bites and sunburn.

4.2. Posology and method of administration

1. Oral.

2. Cutaneous.

1. For relief of the symptoms of dyspepsia, heartburn and indigestion:

Adults and children over 12 years: one level 5ml spoonful dissolved in warm water, to be taken up to 4 times a day.

Not to be taken by children under 12 years old.

2. As an external lotion:

Dissolve one 5ml spoonful in a pint of warm water. Apply with lint or cotton wool.

4.3. Contraindications

For oral use:

Contraindicated in patients with metabolic or respiratory alkalosis, hypocalcaemia, or hypochlorhydria.

Not to be taken by children under 12 years old.

It should be used with extreme caution in patients with congestive heart failure, renal impairment, cirrhosis of the liver, or hypertension, or to patients receiving corticosteroids. Hypersensitivity to sodium bicarbonate.

4.4. Special warnings and precautions for use

Keep all medicines away from children.

Sodium bicarbonate should be avoided in patients on a restricted sodium diet. This medicine contains 1.02g sodium (main component of cooking/table salt) in each 5ml spoonful of sodium bicarbonate. This is equivalent to 51% of the WHO recommended maximum daily intake of 2 g for an adult.

4.5. Interaction with other medicinal products and other forms of interaction

For oral use:

The effects of a number of drugs may be reduced or increased by the alkalinisation of the urine (e.g. aspirin or diflunisal) and reduction in gastric pH brought about by sodium bicarbonate.

The following drugs are reported to be susceptible to inactivation on mixing with sodium bicarbonate solution: adrenaline hydrochloride, benzyl penicillin potassium, carmustine, glycopyrronium bromide, isoprenaline hydrochloride, and suxamethonium chloride.

Sodium-containing preparations should be avoided by patients on lithium because sodium is preferentially absorbed by the kidney resulting in increased lithium excretion and reduced plasma levels.

As a precaution for antacids, in order to minimise the risk of interactions affecting pharmacokinetics of concomitantly administered products, drug administrations should be separated by approximately 2 to 3 hours.

Sodium bicarbonate reduces the absorption of a number of other drugs taken concomitantly. These include ACE inhibitors (captopril, enalapril, and fosinapril), antibacterials and antifungals (azithromycin, cefaclor, cefpodoxime, isoniazid, itraconazole, rifampicin, tetracyclines, ketoconazole and the quinolone group of antibacterials); antivirals (atazanivir, fosamprenavir, tipranavir); antihistamines (fexofenadine); bisphosponates, corticosteroids (deflazacort); digoxin, dipyridamole, antiepileptics (gabapentin and phenytoin), ulcer healing drugs (lansoprazole); levothyroxine, mycophenolate, lipid regulating drugs (rosuvastatin); antipsychotics (sulpiride, phenothiazines), chloroquine, hydrochloroquine, and penicillamine. Antacids should be avoided with nilotinib.

Antacids possibly reduce absorption of bile acids.

4.6. Fertility, pregnancy and lactation

Animal studies are insufficient with respect to effects on pregnancy, embryonal foetal development, parturition and postnatal development. The potential risk for humans is unknown.

Sodium bicarbonate should not be taken in pregnancy or if breastfeeding unless advised by a doctor to do so.

4.7. Effects on ability to drive and use machines

No or negligible influence.

4.8. Undesirable effects

Administration by mouth can cause stomach cramps and flatulence.

Additional undesirable effects associated with oral use of sodium bicarbonate include possible increase in blood pressure, exacerbation of hyperkalaemia, and fluid retention and pulmonary oedema may be caused in those at risk.

Reporting of suspected adverse reactions

Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the Yellow Card Scheme at: www.mhra.gov.uk/yellowcard.

4.9. Overdose

Excessive administration of bicarbonate may lead to hypokalaemia and metabolic alkalosis, especially in patients with impaired renal function. Symptoms include mood changes, tiredness, shortness of breath, muscle weakness and irregular heart beat. Muscle hypertonicity, twitching and tetany may develop, especially in hypocalcaemic patients. Excessive doses of sodium salts may lead to sodium overloading and hyperosmolality.

Treatment of metabolic alkalosis and hypernatraemia is by correction of fluid and electrolyte balance. Replacement of calcium, chloride, and potassium ions may be of particular importance.