Drug Class Description
Antivirals.

Generic Name
Ribavirin [tribavirin]

Drug Description
Ribavirin 6 gInternational non-proprietary name (INN): RibavirinChemical Name: 1-Beta-D-Ribofuranosyl-1H-1,2,4-triazole-3-carboxamide

Presentation
Powder for inhalation solution.

Indications
Virazole is indicated in the treatment of infants and children with severe respiratory syncytial virus (RSV) bronchiolitis.Important: Ribavirin aerosol is more effective when instituted within the first 3 days of the treatment of bronchiolitis. Treatment early in the course of the disease may be necessary to achieve efficacy.Treatment with Virazole must be accompanied by, and does not replace, standard supportive respiratory and fluid management for infants and children with severe respiratory tract infection.Nebulised bronchodilators, when clinically indicated, should be administered with the small particle aerosol generator (SPAG) generator or Aiolos nebuliser turned off.

Adult Dosage
Ribavirin aerosol is only recommended for use in infants and children.Aerosol administration or nebulisation should be carried out in a SPAG or Aiolos nebuliser. Before use read the relevant Operator's Manual for instructions.Treatment is carried out for 12 to 18 hours per day for at least 3 and no more than 7 days and is part of a total treatment programme.The daily dose is prepared by dissolving 6 g of ribavirin in a minimum of 75 ml Water for Injection BP. Shake well. Transfer dissolved drug and dilute to a total volume of 300 ml of Water for Injection BP to give a 20 mg/ml ribavirin solution.In the SPAG unit and Aiolos nebuliser the average concentration for a 7 hour period is 190 µg/l of air.Method of administrationThe aerosol is delivered to an infant oxygen hood from the SPAG aerosol generator or Aiolos nebuliser. Administration by face mask or oxygen tent may be necessary if a hood cannot be employed (see Operator's Manual). However, the volume of distribution and condensation area are larger in a tent and the efficacy of this method of administration has been eva luated only in a small number of patients.

Contra Indications
Ribavirin is contra-indicated in females who are or may become pregnant and it should be noted that ribavirin can be detected in human blood even four weeks after oral administration has ceased.

Special Precautions
Precipitation of the drug in respiratory equipment and consequent accumulation of fluid in the tubing has caused difficulties for patients requiring assisted ventilation.In infants requiring assisted ventilation, Virazole should only be used when there is constant monitoring of both patients and equipment.Directions for use during assisted ventilation are given in the SPAG or Aiolos manual, which should be read carefully before such administration.Occupational exposureNebulised Virazole may potentially escape into the hospital environment during therapy. However, ribavirin was not detected in the erythrocytes, plasma or urine of subjects exposed for a mean of 25 hours during 5 consecutive days. Reports of occupational asthma have been reported rarely although the causal link to ribavirin is unknown since respiratory viruses may induce reactive airways disease in addition to other symptoms including headache, fever, nasal congestion and wheezing. However, care should be exercised, particularly in healthcare workers with pre-existing reactive airways diseases.Health care workers directly providing care to patients receiving aerosolised Virazole should be aware that ribavirin has been shown to be teratogenic in rabbits and rodents but not in baboons. However, no reports of teratogenicity in the offspring of mothers who were exposed to Virazole aerosol during pregnancy have been confirmed and the teratogenic risk of Virazole to humans is unknown. As a precaution, women who are pregnant or trying to become pregnant should avoid exposure to the Virazole aerosol.It is good practice to avoid unnecessary occupational exposure to chemicals whenever possible. Several methods have been employed to lower environmental exposure during Virazole use. The most practical of these is to turn the SPAG or Aiolos Nebuliser off for 5 to 10 minutes prior to prolonged contact.

Interactions
None known.

Adverse Reactions
Side-effects: Several serious adverse events occurred in severely ill infants with life-threatening underlying disease, many of whom required assisted ventilation. These events included worsening of respiratory status, bacterial pneumonia and pneumothorax. The role of ribavirin aerosol in these events has not been determined.Anaemia (often of a haemolytic variety) and reticulocytosis have been reported with oral and intravenous administration. Rarely, cases of non-specific anaemia and haemolysis have been reported spontaneously in association with the aerosol administration of Virazole

Manufacturer
Valeant Pharmaceuticals Ltd

Drug Availability
(POM)

Updated
26 March 2009