Vidarabinum

Vidarabinum Uses, Dosage, Side Effects, Food Interaction and all others data.

A nucleoside antibiotic isolated from Streptomyces antibioticus. It has some antineoplastic properties and has broad spectrum activity against DNA viruses in cell cultures and significant antiviral activity against infections caused by a variety of viruses such as the herpes viruses, the vaccinia VIRUS and varicella zoster virus.

Vidarabinum is a synthetic purine nucleoside analogue with in vitro and in vivo inhibitory activity against herpes simplex virus types 1 (HSV-1), 2 (HSV-2), and varicella-zoster virus (VZV). The inhibitory activity of Vidarabinum is highly selective due to its affinity for the enzyme thymidine kinase (TK) encoded by HSV and VZV. This viral enzyme converts Vidarabinum into Vidarabinum monophosphate, a nucleotide analogue. The monophosphate is further converted into diphosphate by cellular guanylate kinase and into triphosphate by a number of cellular enzymes. In vitro, Vidarabinum triphosphate stops the DNA replication of herpes virus by being incorporated into the DNA strand and preventing the formation of phosphodiester bridges between bases. This ultimately leads to destabilization of the viral DNA strands.

Trade Name Vidarabinum
Generic Vidarabine
Vidarabine Other Names Spongoadenosine, Vidarabine, Vidarabinum
Type
Formula C10H13N5O4
Weight Average: 267.2413
Monoisotopic: 267.096753929
Protein binding

24-38%

Groups Approved, Investigational
Therapeutic Class
Manufacturer
Available Country
Last Updated: September 19, 2023 at 7:00 am
Vidarabinum
Vidarabinum

Uses

Vidarabinum is an antiviral agent used to treat various viral infections.

For treatment of chickenpox - varicella, herpes zoster and herpes simplex

How Vidarabinum works

Vidarabinum stops replication of herpes viral DNA in 2 ways: 1) competitive inhibition of viral DNA polymerase, and consequently 2) incorporation into and termination of the growing viral DNA chain. Vidarabinum is sequentially phosphorylated by kinases to the triphosphate ara-ATP, which is the active form of vidarabine that acts as both an inhibitor and a substrate of viral DNA polymerase. By acting as a substrate for viral DNA polymerase, ara-ATP competitively inhibits dATP leading to the formation of ‘faulty’ DNA. Ara-ATP can also be incorporated into the DNA strand to replace many of the adenosine bases, resulting in the disruption of DNA synthesis.

Toxicity

Acute massive overdosage by oral ingestion of the ophthalmic ointment has not occurred. However, the rapid deamination to arabinosylhypoxanthine should preclude any difficulty. The oral LD50 for vidarabine is greater than 5020 mg/kg in mice and rats. No untoward effects should result from ingestion of the entire contents of the tube. Overdosage by ocular instillation is unlikely because any excess should be quickly expelled from the conjunctival sac.

Elimination Route

Systemetic absorption of vidarabine should not be expected to occur following ocular administration and swallowing lacrimal secretions.

Innovators Monograph

You find simplified version here Vidarabinum

*** Taking medicines without doctor's advice can cause long-term problems.
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