Antivirals, Antifungals and Antiprotozoals Flashcards
(22 cards)
What are the 2 major classes of antiviral drugs used to treat flu?
M2 ion channel blockers
Neuraminidase inhibitors
Give 2 examples of M2 ion channel blockers
Amantadine
Rimantidine
Give 2 examples of neuraminidase inhibitors
Oseltamivir (Tamiflu)
Zanamivir
What is Amantadine used to treat?
Parkinson’s
Influenza A
What is the mechanism of action of M2 ion channel blockers
Block M2 ion channels on viral envelope
Therefore prevent entry of H2 into virus, which prevents viral uncoating and hence also prevents viral DNA release
Give 4 ADRs of M2 ion channel blockers
Dizziness
GI
Hypotension
Confusion
What can the neuraminidase inhibitors be used for?
Influenzas A + B including avian strains and H1N1.
Also useful in M2 ion channel blocker resistant Influenza A
What is the mechanism of action of neuraminidase inhibitors?
Inhibit the viral enzyme neuraminidase that allows release of new viral particles into the circulation
Therefore particles remain bound to exterior side of host cell membrane
How is Tamiflu administered?
What about Zanamivir?
Tamiflu - oral
Zanamivir - dry aerosol - straight to lungs
Give 4 ADRs of neuraminidase inhibitors (3 common and 1 rare)
Common: - GI - Headache - Epistaxis Rare - bronchospasm
What are the 2 major classes of antifungal drug?
Give 2 examples of each
Azoles - clotrimazole, fluconazole
Polyenes - nystatin, amphotericin
How are the antifungal drugs normally administered?
Clotrimazole and nystatin - topical
Fluconazole - oral
What is the mechanism of action of the azoles?
Inhibit ergosterol synthesis which is part of fungal cell wall - hence disrupt cell wall
What is the mechanism of action of the polyenes?
Bind to ergosterol in fungal cell wall - creates pore through which ions leak out - causes lysis
Give 4 ADRs of fluconazole
GI
Headache
Hepatitis
Prolonged QT interval
Give 2 examples of antiprotozoal drugs
Chloroquine
Metronidazole
Give some uses of Metronidazole
- 1st line against C. diff
- Oral infections/surgical infections caused by anaerobes
- Protozoal infections such as trichomonas vaginitis
What is the mechanism of action of Metronidazole?
How does this explain their spectrum of use?
Enters cell, then reduced to produce free radical which causes DNA damage and cell death
No good in aerobes as they cannot reduce the drug molecule
Give 3 ADRs of Metronidazole
GI
Hypersensitivity
Neuro
What is really important about Metronidazole use?
Mustn’t drink alcohol for duration of course + 48 hours
What is the mechanism of action of chloroquine?
Prevents polymerisation of toxic haem to less toxic haemozoin (produced when parasite digests Hb) - leads to lysis of parasite.
Give 3 ADRs of chloroquine
GI upset
Pruritis
Blurred vision
