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Drugs Used to treat infection with Herpes Viruses The important characteristics of all herpes viruses is that once they infect the host, they will remain in the host cells, and they can reactivate to cause clinical problems in the life span of the host. Treatment does not eradicate the viruses but it inhibits replications and helps to control and prevent severe infections. Member of the Herpes virus group includes: Alpha group- Herpes simplex 1 and 2, and Varicella Zoster Virus. The common presentation in primary infection is skin lesions (vesicular lesions). The viruses remain latent in nervous tissues. The viruses reactivate due to several factors and the patients may present with vesicular lesions.
Beta Group- Cytomegalovirus, Human Herpes Virus 6 and Human Herpes Virus 7 The common presentation in primary infection is with sign and symptoms of glandular fever. The viruses remain latent in lymphoid tissues (and white blood cells) The viruses may reactivate due to conditions that suppress the activities of the immune systems and the patients may present with signs and symptoms of pneumonitis, encephalitis, and hepatitis.
Gamma Group- Epestein Barr Virus and Human Herpes Virus 8 The common presentation in primary infection is with glandular fever (at least for EBV). The viruses remain latent in lymphoid tissues (and white blood cells). The viruses may reactivate when the immune system is suppressed and patients would present with signs and symptoms of glandular fever. These groups of viruses are associated with malignancy.
Herpes Simplex 1 and 2 Acyclovir Acyclovir can be taken orally. Ø The standard dose used to treat herpes simplex virus infection is 200mg five times a day for 5 days.
Ø For Immunocompromised patients, the dose can be increased to 400mg five times a day for 5-10 days.
Ø In post-transplant patient and in patient with frequent recurrence, the recommended oral dose for prophylaxis (to prevent infections) is 200 to 400mg four times a day
For neonates and infants Ø 10- 20 mg/kg intravenously three times daily for 2 to 3 weeks is used to treat neonates and infants who have herpes simplex virus infection. Some experts advise up to 15-20 mg/kg three times daily for several weeks to months. Significant number of neonates treated with lower doses of acyclovir would develop relapse in the first 6 months of life. (500mg/m three times a day )
? Intravenous route Ø 10mg/kg every 8 hours for 5-21 days is used to treat all patients with encephalopathy.
Indications for iv therapy o Severe infection o HSV infection in immunocompromised patients o Severe initial genital herpes o Recurrent infection o Encephalitis o Neonatal herpes
Valacyclovir
Dose Standard oral dose- 500 mg two times a day for 5 days
For suppression of recurrences
Indications Like acyclovir.
The advantage
The disadvantage
Famcyclovir It is licensed for use to treat genital herpes. Ø The standard oral dose is 250 mg three times daily for 5 days. Ø It can also be used to suppress frequent recurrent genital herpes. The dose used to suppress recurrences is 125-250 mg two times daily for 6 to 12 months.
Foscarnet
Dose Intravenous route v 60-120 mg/kg three times daily
Indications Ø To treat patients with resistant strains of Herpes Simplex Virus.
Chickenpox
Acyclovir Dose v 800mg five times daily for 7 days
Indications Ø To treat all adult with Chickenpox Ø To treat pregnant woman with chickenpox ( no evidence of any adverse effects on fetus) Ø To treat shingles if patient present within 48 hours
? Intravenous route v 10mg/kg three times a day for 5 days For neonates and infants-250 mg/m three times a day for 5 days
Indications for iv therapy Ø Severe chickenpox (pneumonitis) Ø To treat Immunocompromised patient with chickenpox Ø To treat all neonate who develop chickenpox
Valacyclovir
Dose v 1000 gm orally, three times a day for 7 days Indications Ø Like acyclovir
Advantage
Disadvantage
Famcyclovir For shingles v 250 mg three times, orally, and daily for 7 days
Foscarnet
Dose Intravenous route v 60-120 mg/kg three times daily
Indications Ø To treat patients with resistant strains of chickenpox
Cytomegalovirus
Gancyclovir Dose Intravenous route v 5mg/kg two time/day for 2-3 weeks. Maintenance therapy v 5mg/kg daily for secondary prophylaxis of CMV retinitis
Indications
Ø Cytomegalovirus infection in transplant patients Ø Cytomegalovirus infection in HIV patients Ø Cytomegalovirus infection in neonates and infants with involvement of the central nervous system
Valgancyclovir (oral preparation) For treatment of CMV infection v 900mg two times daily for 21 days For prevention of CMV infection in transplant patients or HIV infected patients v 900mg once daily for several days
Indications Ø Like Gancyclovir NB: is well absorbed from the GI.
Foscarnet Administered only through intravenous route. v 60-120 mg/kg three times daily
Indications To treat patient with Gancyclovir resistant Cytomegalovirus infection. To treat stem cell transplant patient who can not take Gancyclovir ( Neutrophil count <500)
Cidofovir Is administered only intravenously. Dose Intravenous route over 1 hour 5 mg/kg once weekly for 2 weeks then 5mg/kg every two weeks Probenecid 2gm 3 hours before and 1gm after 2 and 8 hours at the end of cidofovir infusion is recommended to reduce the chance of developing nephrotoxicity. In addition rehydration with intravenous fluids is beneficial to prevent nephrotoxicity
Epstein Barr Virus
Acyclovir
Dose v 800mg five times daily for 7 days
Indications Ø Hairy leukoplakia in AIDS patients Ø Early stage of PTLD (not that useful)
Gancyclovir Dose Intravenous v 5 mg/kg bid for 2 to 3 weeks
Valgancyclovir v 500 mg two times a day orally for 2 to 3 weeks
Rituximab
Dose Consult British National Formulary (BNF)
Indication Ø To treat Post Transplant Lymphoproliferative Disorder (PTLD)
Human Herpes Virus 6 Gancyclovir Dose Intravenous route v 5mg/kg two time/day for 2-3 weeks.
Indications
Ø HHV 6 infection in transplant patients (hepatitis, encephalitis, bone ,marrow suppression)
Foscarnet
Dose Intravenous route v 60-120 mg/kg three times daily
Indications
Cidofovir
Dose Intravenous route over 1 hour 5 mg/kg once weekly for 2 weeks then 5mg/kg every two weeks Probenecid 2gm 3 hours before and 1gm after 2 and 8 hours at the end of Cidofovir infusion. Intravenous fluids should be used to prevent nephrotoxicity
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Date this page is updated: 04/03/2007 23:13:30 www. virologynotebook.co.uk
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