Information on anti viral drugs


The challenge with antiviral chemotherapy os to find an agent which will arrest the replication of viruses without

interfering with the metabolism of mammalian cells. Great advances have been made recently in antiviral chemotherapy. A further problem is that by the time a viral infection has been diagnosed using laboratory tests, much of the damage has been done to the host tissues. Table 2.8 provides information on currently available antiviral drugs. Their doses are given are with the descriptions of individual viral diseases.

Aciclovir is an effective agent for herpes simplex and varicella zoster infections, particularly in the immunosuppressed. It does not, however, eradicate the viruses from the body. The use of this agent has been advocated in childhood chickenpox since it reduces the length of illness without reducing the immune response. Cost of this treatment is, however, likely to be prohibitive in many countries. Aciclovir is a useful agent in treating genital herpes, as both primary and prophylactic treatment. Resistance to aciclovir has now been regularly reported. Famciclovir is a newer antiherpes agent which is given as prodrug requiring metabolism first pass to produce the active form penciclovir. Famciclovir has some activity against Epstein-Barr (EB) virus and hepatitis B virus.

Ganciclovir is an antiherpes agent with activity against cytomegalovirus (CMV). Again, resistance to this agent is acquired rapidly on treatment , being detected in 8% of patients on this drug for > 3 months. Currently, ganciclovir is only indicated for life-threatening CMV infection. There is considerable toxicity to monitor when using the drug, principally involving myelosuppression. Ribovirine is active against RNA viruses and good activity has been found against influenza, parainfluenza, mumps, measles and respiratory syncytial virus (RSV). The only clinical use of this drug is in the aerosolised form for RSV infection.

Antiviral drugs
Drug (doses are given in text) Routes of administration Indications Side-effects
Aciclovir Topical Oral Intravenous Herpes zoster Chickenpox (esp. in immunosuppressed) Herpes simplex infection: encephalitis, genital tract, eye Rash, headache, gastrointestinal toxicity, neurotoxicity (i.v. only) Increase in urea and creatinine
Famciclovir Oral Herpes zoster and genital H. simplex infection Rash, headache
Idoxuridine Topical Herpes zoster H. simplex keratitis Local irritation
Amantadine Oral Prophylaxis of influenza A CNS symptoms Nausea
Ribovirine Oral Lassa fever Respiratory syncytial virus infection in infants (inhalation) Reticulocytosis Respiratory depression
Ganciclovir Intravenous/oral Cytomegalovirus infection in immunosuppressed Leucopenia, thrombocytopenia
Zidovudine Oral HIV infection (incl. AIDS) CNS symptoms, anaemia, neutropenia, thrombocytopenia
Concepts of infection
Major manifestations of infection
Principles of management of infection
Diseases due to viruses
DNA viruses
Diseases due to chlamydiae
Diseases due to rickettsiae
Diseases due to bacteria
  • Streptococcal infections
  • Staphylococcal infections
  • Corynebacterial infections
  • Bacillus infections
  • Bordetella infections
  • Salmonella infections
  • Food poisoning
  • Dysentery
  • Other true bacterial infections
  • Mycobacterial infections
Diseases due to spirochaetes
  • Leptospira infections
  • Borrelia infections
  • Treponema infections
Diseases due to fungi (mycoses)
  • Cutaneous fungal infections
  • Subcutaneous fungal infections
  • Systemic fungal infections
Diseases due to protozoa
Diseases due to helminths
  • Trematode (fluke) infections
  • Cestode (tapeworm) infections
  • Nematode (roundworm) infections
  • Zoonotic helminth infections
Diseases due to arthropods
Sexually transmitted diseases
  • Sexually transmitted bacterial diseases
  • Sexually transmitted viral diseases
  • Miscellaneous conditions