- Correction of metabolic acidosis;

- Urine alkalisation in the case of intoxication with weak organic acids, e. g. barbiturates or acetylsalicylic acid;

- Urine alkalisation in order to improve the solubility of drug substances that are poorly soluble in neutral or acid medium, e. g. methotrexate, sulphonamides;

- Urine alkalisation in the case of haemolysis.

The dose depends on the degree of the disorder of the acid-base status. According to the blood gas values the amount to be administered is calculated applying the following formula:

# ml of 1 M (8.4 % w/v) sodium bicarbonate solution = base deficit x kg b.w. x 0.3

(The factor 0.3 corresponds to the proportion of the extracellular fluid in relation to total body fluid).

Example:

If in a patient of 70 kg b.w. the base deficit is 5 mmol/l, then 5 x 70 x 0.3 = 105 ml of 8.4 % w/v Sodium Bicarbonate Intravenous Infusion are to be given.

In neonates and infants the daily dose should not exceed 8 mmol/kg BW/day, administered by slow intravenous infusion, dosage and infusion rate should be controlled carefully.

Correction of metabolic acidosis should not be effected too rapidly. It is advisable to start administering only half of the calculated dose and adjust further doses according to the actual results of blood gas analysis.

For urine alkalisation the dose is adjusted according to the desired pH of the urine and administration should be accompanied by monitoring of the acid-base balance and the water balance. Care should be taken not to exceed the maximum infusion rate stated below.

Maximum daily dose:

According to the correction requirements.

Flow rate:

Up to 1.5 mmol of sodium bicarbonate per kg body weight per hour, corresponding to 1.5 ml of 8.4 % w/v Sodium Bicarbonate Intravenous Infusion/kg bw/h.

Method of administration:

Intravenous use.

The solution must be infused into a central vein.

8.4 % Sodium Bicarbonate Intravenous Infusion must not be administered to patients with

- respiratory and metabolic alkalosis,

- hypernatraemia,

- hypokalaemia.

8.4 % w/v Sodium Bicarbonate Intravenous Infusion should only be administered with particular caution in presence of the following conditions:

- hypoventilation,

- hypocalcaemia,

- increased serum osmolarity,

- further in all situations where sodium intake must be restricted like cardiac insufficiency, oedema, hypertension, eclampsia, severe kidney insufficiency.

Special warnings

Administration of 8.4 % w/v Sodium Bicarbonate Intravenous Infusion may lead to sodium and fluid overload.

If infused undiluted or too rapidly into peripheral veins, 8.4 % w/v Sodium Bicarbonate Intravenous Infusion may cause vein irritation and consecutively phlebitis or thrombosis on account of its alkalinity and its high osmolarity.

Neonates and children (< 2 years old): Rapid infusion (1 ml/min) of hypertonic sodium bicarbonate solutions may produce hypernatraemia, a decrease in cerebrospinal fluid pressure and possible intracranial haemorrhage. Do not administer > 8 mmol/kg BW/day (cf. section 4.2 above).

It must be made absolutely sure that the solution is infused intravenously; accidental intra-arterial infusion may cause shock or loss of an extremity.

Special precautions for use

Patient monitoring should include regular checks of the acid-base balance, the serum electrolyte concentrations and the water balance.

Correction of the acid-base status is always associated with shifts of the electrolyte balance. In particular, the potassium balance is affected. Alkalisation or correction of acidosis promote the potassium influx into cells and may therefore lead to hypokalaemia.

Potassium or calcium deficiencies should be corrected before beginning of the alkalinising therapy.

Urine alkalisation by sodium bicarbonate accelerates the elimination of acid drug substances, e.g. acetylsalicylic acid, and delays the elimination of basic drug substances.

Sodium bicarbonate may interact with gluco- and mineralocorticoids, androgens and diuretics increasing the potassium excretion.

As bicarbonate readily crosses the placental barrier, sodium bicarbonate solutions should only be given to pregnant women if clearly indicated.

Cave eclampsia!

Not applicable.

Administration of 8.4 % w/v Sodium Bicarbonate Intravenous Infusion may lead to hypernatraemia, and serum hyperosmolarity.

Paravenous administration may lead to tissue necrosis.

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.

Symptoms

Overdose may lead to alkalosis, hypernatraemia, and serum hyperosmolarity. When an acidosis is corrected too rapidly, esp. in the presence respiratory disorders, the increased liberation of carbon dioxide may transiently aggravate cerebral acidosis.

Emergency treatment, antidotes

Therapy of alkalosis, depending on its severity: Infusion of physiological saline, substitution of potassium; in marked alkalosis infusion of arginine hydrochloride or hydrochloric acid.

Pharmacotherapeutic group

IV solutions, solutions affecting the electrolyte balance, electrolytes

ATC code: B05B B01

Mechanism of action

The pharmacological properties of sodium bicarbonate result from its physiological role in the HCO₃-/CO₂ buffer system

Pharmacodynamic effects

Exogenously administered sodium bicarbonate rapidly absorbs hydrogen ions from the extracellular space and thus leads to a rise of the pH in the organism.

Secondary pharmacodynamic effects

Alterations in plasma bicarbonate levels can result in changes in the plasma potassium concentration. An increase in bicarbonate concentration causes a shift of potassium into the cells, whereas a decrease has the opposite effect. This effect may aggravate existing hyperkalaemia or cause hypokalaemia.

An increase in pH due to increasing bicarbonate concentration, will also cause a decrease in the ionised calcium concentration. This is due to the increased binding of calcium to plasma proteins, especially albumin. This reduction of plasma calcium levels could contribute to the myocardial depressive effects of bicarbonate administration.

Distribution

Bicarbonate readily passes across the placental barrier but it passes only slowly across the blood-brain barrier.

Elimination

In the kidneys, bicarbonate is filtered in the glomeruli and the major proportion of it is re-absorbed in the tubules. When plasma bicarbonate concentrations rise to above 24 mmol/l, bicarbonate is excreted by the kidneys. Renal bicarbonate re-absorption is reduced under therapy with diuretics of the thiazide group or those acting on the loop of HENLE.

Non-clinical data reveal no special hazard for humans based on conventional studies of safety pharmacology, repeated dose toxicity, genotoxicity, carcinogenic potential, toxicity to reproduction and development.

Disodium edetate

Water for injections

Due to their alkaline pH, sodium bicarbonate solutions are incompatible with most medicinal products. In particular, they must not be administered simultaneously with solutions containing calcium, magnesium or phosphate because of the possibility of precipitation.

- unopened:

2 years.

- after first opening of the container

Not applicable. See section 6.6.

- after dilution

Not applicable. See section 6.6.

Do not store above 25° C.

To avoid formation of crystals, do not refrigerate or freeze.

Bottles of colourless glass type I (Ph. Eur.), sealed with rubber stoppers, contents: 100 ml, 250 ml, 500 ml

supplied in packs of

1 × 100 ml, 10 × 100 ml

1 × 250 ml, 10 × 250 ml

1 × 500 ml, 10 × 500 ml

Not all pack sizes may be marketed.

The containers are for single use only. Discard container and any unused content after use.

Only to be used if the solution is clear and colourless and if the bottle and its closure are undamaged.

This medicinal product is an almost saturated solution. Crystals which may possibly have developed during storage can be dissolved by simply warming the bottle.

As an additional safety measure against crystals that might be inadvertently infused with the solution, it is recommended to use an infusion set fitted with an integral fluid filter.

The solution should be administered immediately after connecting the container to the giving set.

Any unused medicinal product or waste material should be disposed of in accordance with local requirements.