Ribavirin

Indications

Ribavirin is used for: Chronic hepatitis C

Adult Dose

Oral Chronic hepatitis C Adult: Ribavirin with peginterferon alfa 2b <66 kg (145 lb): 800 mg/day (400 mg AM and 400 PM) + peginterferon 1.5 mcg/kg/Wk SC 66-80 kg (145-177 lb): 1000 mg/day (400 mg AM and 600 PM) + peginterferon 1.5 mcg/kg/Wk SC 81-105 kg (178-231 lb): 1200 mg/day (600 mg AM and 600 PM) + peginterferon 1.5 mcg/kg/Wk SC >105 kg (231 lb): 1400 mg/day (600 mg AM and 800 PM) + peginterferon 1.5 mcg/kg/Wk SC Recommended therapy duration Genotype 1: 48 wks Genotype 2,3: 24 wks Patients who previously failed therapy: 48 wks, regardless of genotype Ribavirin with interferon alfa 2b <75 kg: 400 mg PO qAM, 600mg PO qPM plus 3 million IU three times weekly SC for 24-48 wks >75 kg: 600 mg PO q12hr plus 3 million IU three times weekly SC for 24-48 wks Recommended therapy duration Patients previously untreated with interferon: 24-48 wks Patients who relapse following inteferon monotherapy: 24 wks Hepatic impairment: Severe: Contraindicated.

Child Dose

Oral Chronic hepatitis C Child: >3 yr <47 kg (103 lb): 15 mg/kg/day, plus peginterferon alfa-2b 60 mcg/m² SC qWeek 47-59 kg (103-131 lb): 400 mgPO q12hr, plus peginterferon alfa-2b 60 mcg/m² SC qWeek 60-73 kg (132-162 lb): 400 mg PO qAM, 600 mg PO qPM plus peginterferon alfa-2b 60 mcg/m² SC qWeek >73 kg (162 lb): 600 mg PO q12hr plus peginterferon alfa-2b 60 mcg/m² SC qWeek Length of treatment determined by genotype; genotypes 2 or 3 administer for 24 weeks, for genotype 1 is 48 weeks

Renal Dose

Renal impairment: CrCl (ml/min) <50 Avoid usage.

Administration

May be taken with or without food. Take consistently w/ respect to meals, either always w/ or always w/o meals.

Contra Indications

Hypersensitivity. History of severe unstable cardiac disease, haemoglobinopathies, severe, debilitating medical conditions. CrCl <50 mL/min, severe hepatic impairment or decompensated liver cirrhosis. Male partners of pregnant women. Childn and adolescents w/ history of, or existing psychiatric disorders. Pregnancy and lactation.

Precautions

Patient w/ history of CHF, MI and/or previous or current arrhythmic disorders, ophthalmologic disorders, thyroid disorders, low CD4 count, substance use/abuse, COPD and asthma. Renal and hepatic impairment. Childn. Patient Counselling This drug may cause fatigue, somnolence or confusion, if affected, do not drive or operate machinery. Monitoring Parameters Monitor haematologic, cardiac, resp and ophth function; growth in paed patients; pregnancy tests mthly during and for 6 mth after discontinuation.

Pregnancy-Lactation

Pregnancy Therapy is contraindicated for use in pregnant women and in men whose female partners are pregnant; obtain negative pregnancy test before initiating therapy; patients should have periodic pregnancy tests during treatment and during the 6-month period after treatment has been stopped Animal data Based on animal data, ribavirin use in pregnancy may be associated with birth defects; interim data from Pregnancy Registry are insufficient to identify a drug-associated risk of birth defects, miscarriage, or adverse maternal or fetal outcomes; the drug is known to accumulate in intracellular components from where it is cleared very slowly; in animal studies, drug exposure was shown to have teratogenic and/or embryocidal effects Infertility Based on animal data, therapy may impair male fertility; in animal studies, these effects were mostly reversible within a few months after drug cessation Contraception Females of reproductive potential should use effective contraception during treatment and during 6 months post-therapy based on a multiple-dose half-life (t1/2) of ribavirin of 12 days (e.g., 15 half-lives for ribavirin clearance from the body) Male patients and their female partners should use effective contraception during treatment and for 6-month post-therapy period Lactation There are no data on presence of ribavirin in human milk or effects on breastfed infant or milk production; the developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for therapy and any potential adverse effects on breastfed infant from therapy or from the underlying maternal condition

Interactions

May worsen neutropenia induced by interferon alfa. May increase risk of adverse effects when used with nucleoside reverse transcriptase inhibitors. Potentially Fatal: Risk of fatal hepatic failure, peripheral neuropathy and pancreatitis when used with didanosine. Increased risk of severe neutropenia and anaemia when used with zidovudine.

Side Effects

Side effects of Ribavirin : >10% Fatigue (60-70%), Headache (63-66%), Hemolysis (61-64%), Myalgia (61-64%), Nausea (38-47%), Rigors (40-43%), Fever (32-41%), Insomnia (26-39%), Decreased Hgb (25-36%), Depression (23-36%), Hyperbilirubinemia (24-34%), Arthralgia (29-33%), Alopecia (27-32%), Irritability (23-32%), Musculoskeletal pain (20-28%), Rash (20-28%), Anorexia (21-27%), Dizziness (17-26%), Pruritus (13-21%), Flu-like syndrome (13-18%), Dyspnea (17-19%), Nasal congestion (13-18%), Dyspepsia (14-16%), Impaired concentration (10-14%), Thrombocytopenia (6-14%), Sinusitis (9-12%), Vomiting (9-12%), Emotional lability (7-12%), Decreased WBC; ANC <500 /cu.mm (5-11%) 1-10% Hemolytic anemia (~10%), Weakness (9-10%), Chest pain (5-9%), Taste perversion (6-8%), Nervousness (~5%)

Mode of Action

Ribavirin is a synthetic nucleoside which has inhibitory action against respiratory syncytial virus, influenza virus and herpes simplex virus. The mechanism of action is not clear. It may act at several sites including cellular enzymes to interfere with viral nucleic acid synthesis. The mono- and triphosphate derivatives are known to be responsible for the antiviral action of the compound.