Mechanism of Action
The drug is a synthetic precursor of vitamin $K$ (vitamin $K_3$). Once inside the body, menadione sodium bisulfite is transformed into the active form of vitamin $K$. In the liver, it initiates a crucial biochemical process — the synthesis of plasma coagulation factors: prothrombin (factor II), proconvertin (factor VII), Christmas factor (factor IX), and Stuart-Prower factor (factor X), as well as the anticoagulant protein $C$.
In addition to its hepatobiliary effects, vitamin $K$ participates in extrahepatic processes, notably the synthesis of osteocalcin, a calcium-binding bone matrix protein.
Pharmacological Effects
The primary pharmacological effect of the drug is its hemostatic action. Clotting factors have a short half-life and rapidly degrade; vitamin $K$ deficiency impairs their synthesis, leading to bleeding. Administration of Vikasol restores the plasma pool of coagulation factors, normalizes coagulation profiles, and prevents hemorrhagic complications.
Indications for Use
The main purpose of prescribing the drug is to treat hemorrhagic syndrome associated with hypoprothrombinemia. Key clinical indications include:
- Liver and biliary tract pathologies: hepatitis, liver cirrhosis (impaired factor synthesis), obstructive jaundice (impaired vitamin $K$ absorption due to bile deficiency).
- Malabsorption disorders: malabsorption syndrome, obstructive jaundice.
- Medication-induced causes: overdose of indirect anticoagulants (vitamin $K$ antagonists).
- Prophylactic use: preparation for major surgical interventions to prevent bleeding.
Side Effects and Special Considerations
Allergic reactions may occur during treatment: skin rash, pruritus, erythema, and bronchospasm. Intravenous administration carries a risk of anaphylactoid reactions.
A specific feature of vitamin $K_3$ (Vikasol) is the risk of hemolytic anemia and hyperbilirubinemia in newborns. Therefore, natural phytomenadione (vitamin $K_1$) is preferentially used for the prophylaxis of hemorrhagic disease of the newborn.
Administration and Dosage
The drug is available as 0.015 g tablets and a 1% solution in 1 ml ampoules.
- Oral: 1–2 tablets 1–2 times daily. The maximum single dose (MSD) is 0.03 g, and the maximum daily dose (MDD) is 0.06 g.
- Parenteral (intramuscular): 0.01–0.015 g 2–3 times daily. The parenteral route is especially important in malabsorption syndromes and obstructive jaundice, where intestinal bile delivery is impaired, which is otherwise required for the absorption of lipid-soluble forms.