ANTI VIRAL DRUGS.pptx by Dr GOpal Gudsurkar

anti viral drugs simple and explained with dosages of important clinical diseases

1. ANTI VIRAL DRUGS Dr.Gopal Gudsurkar M.D. DNB.

2. Introduction

3. The Major sites of Antiviral drug action

4. Classification

5. Anti Herpes Virus Drugs Acyclovir It is phosphorylated by a viral thymidine-kinase, then metabolized by host cell kinases to nucleotide analogs. The analog inhibits viral DNA-polymerase. Uses: Bells Palsy 400 mg TDS for 10 days [ Give within 3 days] OR valacyclovir 1 gm TDS for 7 days. Herpes simplex meningitis /encephalitis : 10mg/kg i.v. 8 hrly for 14 days.

6. Herpes zoster (shingles): 800 mg 5 times daily for 7 to 10 days . OR valacyclovir 1 gm TDS for 7 days. Disseminated zoster (extensive cutaneous lesions or visceral involvement):  IV:   10 mg/kg/dose every 8 hours for 14 days. Varicella (chickenpox), treatment : 800 mg 5 times daily for ≥5 to 7 days and until all lesions have crusted . OR valacyclovir 1 gm TDS for 7 days.  Ideally initiate therapy within 24 hours of symptom onset, but may start later if the patient still has active lesions.

7. Varicella zoster virus, encephalitis (off-label use): IV:  10 mg/kg/dose every 8 hours ; some experts use higher doses, up to 15 mg/kg/dose every 8 hours, although tolerability may be a limiting factor. The duration is 10 to 14 days . Genital Herpes : 5 % ointment local application for 5 to 6 times a day for 10 days. OR Treatment, recurrent episode:   Oral:  800 mg twice daily for 5 days  or  800 mg 3 times daily for 2 days.  OR valacyclovir 1 gm BD for 7 days.

8. Anti CMV drugs Valganciclovir: Cytomegalovirus, prophylaxis in solid organ transplant recipients: Oral: 900 mg once daily. Cytomegalovirus, treatment, esophagitis or colitis in patients with HIV  Cytomegalovirus retinitis. Cidofovir Foscarnet Letermovir : 480 mg OD after BMT or Renal transplant start between 0 to 7 days post Transplant upto 100 days.

9. Anti Influenza Drugs Oseltamivir : Inhibits Viral Neuraminidase enzyme and stops release of virions from infected cells. 75 mg BD for 5 days. Start within 48 hours. Peramivir : 600 mg i.v. slowly over 20 min. single dose. Baloxavir marboxil :40 mg for <80 kg person. And 80 mg for >80 kg person. Single dose.

10. Hepatitis B The goals of antiviral therapy are suppression of HBV DNA, loss of HBeAg (in patients who were initially HBeAg positive), and loss of HBsAg. Entecavir : 1 st line drug for CHB. Taken empty stomach 0.5 to 1 mg OD TDF is used in case of resistance. Tenofovir disoproxil fumarate : Can be given in pregnancy. 300 mg OD. Tenofovir alafenamide : 25 mg OD

11. IFN alpha: PEG IFN more effective. C/I in pregnancy. PEP : HBIG should be administered intramuscularly as soon as possible after exposure when indicated. The effectiveness of HBIG when administered >7 days after percutaneous, mucosal, or nonintact skin exposures is unknown. HBIG dosage is 0.06 mL/kg. Complete Vaccination if not vaccinated.

12. Anti Hepatitis C Drugs 6 genotypes and multiple subtypes. Genotype 1 most common. Sofosobuvir NS5B inhibitor [RNA polymerase ] : Taken with fatty food. Active against all genotypes. 400 mg OD and given combination with Ledipasvir or simperevir . Or Velpatasvir . NS5A inhibitors: Daclatasvir , Velpatasvir ,Ledipasvir. Ribavarin : Used in combination with PEG IFN alpha and sofosbuvir in decompensated cases.

13. Covid 19 Remdesivir : active against nipah and Ebola also. 200 mg i.v. on day 1 then 100 mg i.v. OD for 10 days.