Ampoules - Meylon 84

8.4% Sodium Bicarbonate Intravenous Infusion B.P.

Therapeutic Class

Systemic Alkalinisation Electrolyte Solution

Description and Composition

A clear, colorless, sterile solution each 25 ml of which contains:

• Sodium Bicarbonate B.P.: 2.1 grams
• Water for Injections: q.s.

Pharmacological Effects

• Bicarbonate is an alkalinizing agent and intravenous bicarbonate-containing salts are often used to manage severe metabolic acidosis.
• Systemic alkali therapy acting as a buffer helps in the correction of acidosis and improves hemodynamic status.
• Intravenous infusion of sodium bicarbonate can enhance the excretion of salicylate by elevating intraluminal pH, aiding in secretion and trapping of salicylate in the tubular lumen.
• Provides the following electrolytes in each liter of fluid:
  • Sodium: 1000 mEq
  • Bicarbonate: 1000 mEq
• Each ampoule of 25 mL provides 25 mEq of sodium and 25 mEq of bicarbonate.
• The pH range is 7.5 – 9.5.

Indications

• In the management of metabolic acidosis such as ketoacidosis, hyperchloremic acidosis, and lactic acidosis.
• Bicarbonate therapy is also indicated for severe metabolic acidosis after cardiac arrest.
• Management of overdosage or poisoning with toxins such as salicylate, methanol, and ethylene glycol in conjunction with other measures.

Dosage and Administration

Bicarbonate solution should be used in accordance with the weight and clinical condition of the patient. Generally, sufficient bicarbonate should be administered to achieve pH levels above 7.1. The amount of bicarbonate required varies and also depends upon the rate of ongoing acid production.

As a general guideline, the amount of bicarbonate administered is determined as follows:

Desired increase in bicarbonate concentration x 0.5 x body weight (kg)

No more than half of the bicarbonate concentration deficit should be corrected over a 3-4 hour period without monitoring arterial blood gases. The response to bicarbonate administration should be closely monitored to avoid volume overload and the induction of alkalosis. In severe cases, dialysis with bicarbonate dialysate should be considered.

Adverse Effects

• Hypernatremia and hyperosmolarity may occur.
• Hypokalemia: Correction of acidosis leads to the movement of potassium inside the cells causing hypokalemia.
• Hypercapnia: Bicarbonate administration can result in a rapid increase in PCO2, which can diffuse across cell membranes, worsening intracellular acidosis.
• Alkalosis, tetany, and carpopedal spasm may occur. Rapid correction of metabolic acidosis can lead to tetany as a result of a decrease in ionized calcium concentrations.

Contraindications

• Alkalosis.
• Renal insufficiency.

Precautions

• The sodium bicarbonate content of Meylon is 84 mg/mL. Care is required in cases where salt intake is restricted, such as in hypertensive patients, congestive heart failure, or pre-eclampsia. Care is required to avoid volume overload.
• Care is required in patients with preexisting potassium deficiency, as it can promote the movement of extracellular potassium into the cells, worsening hypokalemia. Cardiac monitoring for arrhythmias is essential in such patients.
• Overcorrection of acidosis can lead to alkalosis with the risk of tetany.
• Care is required in administration as extravasation of the solution may result in tissue necrosis at the site of administration.

Overdosage

Excessive administration may lead to metabolic alkalosis, hypokalemia, and tetany. Symptoms may include tiredness, muscular weakness, shortness of breath, and muscle twitching.

Management consists mainly of appropriate correction of electrolyte balance. Replacement of potassium, calcium, and chloride is of particular importance.

Tonicity and Osmolarity

• Hypertonic solution having a tonicity of 1000.
• Hyperosmotic solution (~2000 mOsm/L).

Caloric Value

Nil

Pharmaceutical Precautions

• Store at room temperature. Protect from sunlight.
• Do not use if the ampoule is leaking, the solution is cloudy, or contains foreign matter.
• Discard unused portion.
• Keep all medicines out of the reach of children.
• Shelf life is three years from the date of manufacturing.

Packaging

25 mL in polyethylene, twist-off, plastic ampoules.