Antivirals are medications that directly attack VIRUSES. They are not ANTIBIOTICS, which attack BACTERIA. Antivirals are also much newer than antibiotics. Until recently, antivirals were mainly used against severe life-threatening viral conditions. They should be distinguished from viricides,which are not medication but destroy virus particles outside the body.However, modern antivirals exist against FLU, GENITAL HERPES, HIV, VIRAL HEPATITIS, and other VIRAL CONDITIONS.

Antiviral drugs are medicines that cure or control virus infections. Exclusive of the antiretroviral agents used in HIV (AIDS) therapy, there are currently only 11 antiviral drugs available, covering four types of virus. Acyclovir (Zovirax), famciclovir (Famvir), and valacyclovir (Valtrex) are effective against herpesvirus, including herpes zoster and herpes genitalis. They may also be of value in either conditions caused by herpes, such as CHICKENPOX and SHINGLES. These drugs are not curative, but may reduce the pain of a herpes outbreak and shorten the period of viral shedding.Amantadine (Symmetrel), oseltamivir (Tamiflu), rimantidine (Flumadine), and zanamivir (Relenza) are useful in treatment of INFLUENZA virus. Amantadine, rimantadine, and oseltamivir may be administered throughout the flu season as preventatives for patients who cannot take influenza virus vaccine.Cidofovir (Vistide), foscarnet (Foscavir), and ganciclovir (Cytovene) have been beneficial in treatment of cytomegalovirus in immunosupressed patients, primarily HIV-positive patients and transplant recipients. Ribavirin (Virazole) is used to treat respiratory syncytial virus. In combination with interferons, ribavirin has shown some efficacy against HEPATITIS C, and there have been anecdotal reports of utility against other types of viral infections.As a class, the antivirals are not curative, and must be used either prophylactically or early in the development of an infection. Their mechanism of action is typically to inactivate the enzymes needed for viral replication. This will reduce the rate of viral growth, but will not inactive the virus already present. Antiviral therapy must normally be initiated within 48 hours of the onset of an infection to provide any benefit. Drugs used for influenza may be used throughout the influenza season in high risk patients, or within 48 hours of exposure to a known carrier. Antiherpetic agents should be used at the first signs of an outbreak. Anti-cytomegaloviral drugs must routinely be used as part of a program of secondary prophylaxis (maintenance therapy following an initial response) in order to prevent reinfection in immunocompromised patients.


INDICATION-any of the conditions for which a particular drug treatment may be prescribed.


Shingles: Introduction
Herpes zoster is an infectious viral infection that is believed to be caused by the re-activation of a previous chickenpox infection, often from many years before. Shingles is a painful condition characterized by the appearance of a skin rash. When the immune system of the body becomes weak the virus may get reactivated and this can result in appearance of shingles symptoms.
Any individual who has suffered from chicken pox can develop shingles. However the shingles symptoms are most often seen in individuals who are around 60 years old.

This condition is caused by the VARICELLA-ZOSTER VIRUS, and this virus also causes chicken pox disease. In fact once a person has had the chicken pox this virus remains within the body in a dormant or latent condition. When the immune system of the body becomes weak the virus may get reactivated and this can result in appearance of shingles symptoms.
Symptoms of Shingles:
The shingles symptoms begin with increased sensitivity of skin along with a burning pain. Some patients may also experience tickling or tingling along with numbness in the areas. In such a stage it is often difficult to determine the reason for the pain. The areas that are typically affected include the head, abdomen, neck, face and arm or leg. In rare cases areas of the face like the nose and eyes may also be affected. Along with tingling of skin patients also tend to experience other problems like stomach ache, chills, diarrhea along with fever.


Type A influenza subtype H1:

The H1 subtype of influenza is a strain of the type A influenza virus that can cause cause serious illness and result in pandemics. Influenza is viral respiratory infection. The virus is very contagious and can cause severe illness especially in patients who are very young or old or have some other medical condition as well. The severity of symptoms can vary but usually involves respiratory and constitutional (e.g. headache, aching muscles) symptoms. The influenza virus can mutate and produce different strains though the symptoms are the same.

Symptoms of Type A influenza subtype H1:

  • Runny nose
  • Sore throat
  • Aching muscles
  • Headache
  • Cough

Type A influenza subtype H1: Complications

  • Pneumonia
  • Febrile seizures - children
  • Exacerbation of pre-existing asthma
  • Exacerbation of pre-existing chronic obstructive pulmonary disease
  • Exacerbation of pre-existing heart failure

Causes of Type A influenza subtype H1:

*RNA viruses of the family Orthomyxoviridae (the influenza viruses)

Treatments for Type A influenza subtype H1:

Antiviral medications may reduce the severity and duration of symptoms in some cases. Rest and fluids aid recovery. Medications may be used to alleviate symptoms such as pain, fever and nasal congestion. Regular flu shots can prevent influenza infections.


Encephalitis: Introduction

Encephalitis, or inflammation of the brain tissue, is rare, When it strikes, it can be very serious, causing personality changes, seizures, weakness, and other symptoms depending on the part of the brain affected. Children, the elderly, and those with a weak immune system are most vulnerable. It is usually caused by one of several viral infections, so it's sometimes referred to as viral encephalitis.

Symptoms of Encephalitis:

  • Mild fever - in mild cases
  • Mild early symptoms
  • Sudden fever
  • Headache
  • Vomiting

Encephalitis: Complications:

  • Permanent brain damage
  • Death
  • Lung complications (see Lung symptoms)
  • Heart complications
  • Meningitis

Treatments for Encephalitis:

  • Emergency hospitalization - often required; encephalitis is potentially fatal.
  • Antiviral medications
  • Antibiotics
  • Injected antibiotics
  • Anticonvulsants - for seizures or their prevention
  • Corticosteroids - reduce brain swelling
  • Sedatives - may be necessary
  • Treatments to relief intracranial pressure
  • Hospital admission
  • Panadol
  • Paracetamol
  • Fluid hydration
  • Antiviral agents
  • Acyclovir
  • Bed rest
  • Supportive treatment
  • Analgesics
  • Acetaminophen
  • Tynelol
  • Ibuprofen
  • Ibuprin
  • Adansetron
  • Zofran
  • Croperidol
  • Inapsine
  • Zovirax




Brand names: Acevir®, Innovirax®, Cyllanvir®
Specific class: Synthetic nucleoside
Dosage Forms: 200 mg, 400 mg, 800 mg tablets,oral, injected, and topical
Side effects:nausea,vomiting, diarrhea,headache,malaise,renal failure;
Contraindication: Acyclovir for injection is contraindicated for patients who develop hypersensitivity to acyclovir or valacyclovir.
Pregnancy Category: Pregnancy Category B


Brand names: Valtrex®
Specific class: Acyclic purine nucleoside analog
Dosage Forms: 500 mg, 1000 mg caplets;
Side effects:headache,nausea,vomiting,dizziness ,abdominal pain;
Contraindication:Hypersensitivity to drug, its components, or acyclovir
Pregnancy Category: Pregnancy Category B


Brand names: Famvir®
Specific class:purine analog
Dosage Forms: 125 mg, 250 mg, 500 mg tablets;
Side effects: vomiting,dysmenorrhea ,flatulence,migraine,renal failure
Contraindication: It should not be given to patients with kidney disease or an allergy to famciclovir. The safety of the drug in children or in women who are pregnant or breastfeeding has not been established
Pregnancy Category: Pregnancy Category B

Didanosine (ddI)
Brand names: Videx®
Specific class:nucleoside reverse transcriptase inhibitor
Dosage forms: Delayed-release capsules, powder for oral solution, tablets
Side effects: headache, dizziness, insomia, diarrhea, nausea, vomiting, abdominal pain dry mouth and anorexia.
Contraindication: contarndicated in patients hypersensitive to drugs or its components.
Preganacy Category: Preganacy Category B

Brand names: Sustiva® and Stocrin®
Specific class:non-nucleoside reverse transcriptase inhibitor
Dosage form: Capsules: 50 mg, 100 mg, 200 mg
Side effects: insomnia, confusion, memory loss, and depression, are common rash, nausea, dizziness and headache may occur and can produce a false positive result in some urine tests for marijuana.
Contraindication: Clinically-significant hypersensitivity to efavirenz or any component of the formulation; concurrent use of cisapride, midazolam, triazolam, voriconazole, or ergot alkaloids.
Preganacy Category: Preganacy Category C

Brand names: Relenza®
Specific class: Neuraminidase inhibitor
Dosage form: Powder for inhalation: 5 mg/blister
Side effects: headache, dizziness, diarrhea, nausea, vomiting, cough.
Contraindication:Oral dosing of zanamivir is ineffective, limiting dosing to the inhaled route. This restricts its usage, as treating asthmatics could induce bronchospasm.The FDA has issued a Public Health Advisory warning that it has received some reports of respiratory problems following inhalation of zanamivir by patients with underlying asthma or chronic obstructive pulmonary disease. The zanamivir package insert contains precautionary information regarding risk of bronchospasm in patients with respiratory disease.
Preganacy Category:Preganacy Category C

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