36)Antiviral drugs Flashcards
Antiviral drugs
Used to treat viral infections
Many antiviral drugs are purine or pyrimidine analogues
Many are prodrugs ⇢ must be phosphorylated by viral/cellular enzymes in order to become active
Classification
Anti-herpes viral agents
- Acyclovir, Valacyclovir
- Idoxuridine + Tromantadine
Anti-influenza viral agents
- Amantadine, Rimantadine
- Oseltamivir + Zanamivir
Used too treat cytomegalovirus infection:
- Ganciclovir, Cidofovir + Fomivirsen
Classification - Anti-retroviral agents/Anti-HIV drugs + Drugs used for viral hepatitis
NRTIs - Nucleoside reverse transcriptase inhibition
- Zidovudine + Didanosine
NNTIs - Non ‘’
- Nevirapine
Protease inhibitors
- Ritonavir
Used for viral hepatitis
- Interferon alpha + Ribavirin
Characteristics
- Able to enter cells infected by a virus
- Interfere with viral nucleic acid synthesis/regulation
- Interfere w/ability of virus to bind to cells
- Stimulates body’s immune system - healthy immune system works synergistically w/drug
- Purine/Pyrimidine analogues
- Clinical efficiency ⇢ depends on achieving inhibitory concentration at site of infection within infected cells
Acyclovir
PD ⇢ inhibits viral DNA synthesis
PKs:⇢ poor oral absorption, Lipophilic + excreted by kidneys mainly
Side effects:
- Nausea, diarrhoea + headache
- Rashes, sweating + ⇣ BP
- Nephrotoxicity + Neurotoxicity
Clinical use
- Treats herpes simplex + varicella-zoster virus
Anit-Influenza drugs
Caused by 3 RNA viruses- Influenza A, B or C
Neuraminidase inhibitors ⇢ Oseltamivir + Zanamivir
- Inhibit neuraminidase enzyme ⇢ locks virus into cell
- Oseltamivir ⇢ orally taken ⇢ prevents flu for those over 1 yrs age
- Zanamivir ⇢ treats those over 7 yrs
- Both immediately effective after flu symptoms have set
- Side effects ⇢ Nausea, vomiting, runny nose, cough + diarrhoea
M2 protein inhibitors ⇢ adamantane derivatives
HIV treatment NRTIs
Nucleoside Reverse transcriptase inhibitors ⇢ Zidovudine + Didanosine
- Prevent acute infection of cells ⇢ do not affect already infected cells
- Resistance to these may occur ⇢ ineffective long term
- Side effects ⇢ neuropathy
- Zidovudine ⇢ hepatotoxicity
- Didanosine ⇢ pancreatitis
NNTIs
Nevirapine
- Non nucleoside antimetabolites
- Prone to adverse DDIS
- Side effects ⇢ rash + CNS toxicity
Protease inhibitors
Saquinavir
- Inhibit protease enzyme ⇢ responsible for virus assembly
- Side effects ⇢ unusual fat distribution + insulin resistance