Antimicrobial chemotherapy-antivirus and antifungal drugs

Question 1

What are characteristics of polyenes? (antifungal)`

Answer 1

Polyene drugs bind to ergosterol, present in the fungal cell wall but not in the bacterial cell wall, and this results in an increase in the permeability of the cell wall.
Active against both yeasts and filamentous fungi.
Unfortunately, polyenes also bind to other sterols (e.g. cholesterol) in mammalian cell membranes and this is the reason for their toxicity.

Question 2

What are characteristics of Amphotericin B (polyene)?

Answer 2

The only drug available for intravenous use and is used for the treatment of serious systemic fungal infection.
Extremely toxic with a wide range of side effects including renal, hepatic and cardiac toxicity.
Resistance to amphotericin B is unusual

Question 3

What are characteristics of Nystatin? (polyene)

Answer 3

available for topical use only
(e.g. in creams for fungal skin infections, in pessaries for vaginal candida infections,
oral suspension for oral and oesophageal candidiasis)

Question 4

Describe the azoles (anti fungal drug)?

Answer 4

the azoles are going to inhibit the ergosterol synthesis and prevent proper formation of the cell wall

Question 5

What are characteristics of fluconazole (azole)?

Answer 5

treatment of yeast infection
no serious toxicity problems
resistance among some candida species

Question 6

What are characteristics of Itraconazole (azole)?

Answer 6

for treating yeast and filamentous fungi

Question 7

What is Voriconazole (azole) used to treat?

Answer 7

aspergillosis

Question 8

Describe Allylamines (antifungal drugs)?

Answer 8

suppress ergosterol synthesis but act at a different stage of the synthetic pathway from azoles

Question 9

What is the only allyamine in common use?

Answer 9

terbinafine

Question 10

What are allyamines used to treat?

Answer 10

Active against dermatophyte infections of the skin (e.g., ringworm, athlete’s foot) and nails (onychomycosis).
Mild infections are treated topically and more serious infections (including onychomycosis) orally.

Question 11

Describe Echinocandins? (antifungal)

Answer 11

Inhibit the synthesis of glucan polysaccharide in several types of fungi

Question 12

What are echinocandins used to treat?

Answer 12

These agents are used for serious Candida and
Aspergillus infections, usually on specialist advice

Question 13

What do you prescribe for a flu?

Answer 13

If there is a flu, no prescription of antibiotics, instead opt for anti-viral

Question 14

What is the availibility to treat viruses like?

Answer 14

There are no virucidal agents (i.e. those that will kill the virus)
but that they are all virustatic (i.e. inhibit growth and/or replication)

Question 15

Describe the common structure of antiviral drugs?

Answer 15

Many anti-viral drugs are nucleoside analogues which
interfere with nucleic acid synthesis.

Question 16

What are characteristics of the anti-herpes virus drugs (anti viral drugs)?

Answer 16

Herpes viruses are a clinically important group.
They are not all equally sensitive to anti-viral agents.
Treatment is most effective if started early but does not eradicate any of these viruses-treats infection.

Question 17

Give characteristics of Aciclovir? (Anti-herpes virus drugs)

Answer 17

Nucleoside analogue.
It is specific for virus-infected cells and has very low toxicity for uninfected host cells.
Extremely active against Herpes Simplex virus and is active against Varicella Zoster virus.

Question 18

What are Valaciclovir and Famciclovir used to treat (Anti-herpes drugs)?

Answer 18

Treatment of HSV and shingles

Question 19

What is Valganciclovir?

Answer 19

pro drug, becomes itself when metabolized in body
good choice for CMV
presents bone marrow toxicity

Question 20

What is Ganciclovir?

Answer 20

coming from metabolism of valganciclovir
active against CMV
toxic
restricted to treating patients that are in the presence of or having life threatening infections or if they are immunocompromised

Question 21

What is Foscarnet?

Answer 21

can be used for HSV, VZV and CMW (resistant to nucleoside analogues)

Question 22

What is Cidofovir?

Answer 22

Cidofovir is used for CMV retinitis when other anti-viral drugs are inappropriate.

Question 23

What is zidovudine (Anti-HIV drugs)?

Answer 23

Is a nucleoside analogue interfering with the action of reverse transcriptase.
(It slows the replication of the virus but does not kill it).
Had side effects of anaemia and neutropenia

Question 24

What do we nowadays use to treat HIV?

Answer 24

Combination therapy with at least three drugs
is now normal practice in HIV treatment.
Drugs are active on at least two different stages of HIV replication.
Two nucleoside analogue reverse transcriptase inhibitors,
plus either a non-nucleoside reverse transcriptase inhibitor (nevirapine)
or a viral protease inhibitor (saquinavir).

Question 25

What is used to asses response to treatment?

Answer 25

patients viral load and CD4+ cell count

Question 26

What is interferon-alpha? (drugs for chronic hepatitis b and c)

Answer 26

Protein that, forms part of the host immune response.
Produced by genetic engineering and is used to treat selected chronic hepatitis B and C infections
-has to be given intraveneously

Question 27

What is ribavirin?

Answer 27

can be used in combination with interferon alpha for successful treatment of chronic hepatitus C

Question 28

What is adefovir dipivoxil and lamivudine?

Answer 28

Lamivudine used mainly for HIV treatment, with adefovir dipivoxil also suitable
for selected patients with hepatitis B.

Question 29

What are Zanamivir and Oseltamivir used for?

Answer 29

drugs for viral respiratory infections
Treatment of influenza A or B within 48 hours of the onset of symptoms and for post-exposure prophylaxis.

Question 30

What is ribavirin used for?

Answer 30

drug for viral respiratory infections
Occasionally used for treatment of severe Respiratory Syncytial Virus (RSV) infections. It must be inhaled as a fine spray to reach the site of infection
in the lungs, administration is difficult.

Question 31

What is remdesivir?

Answer 31

drug for viral respiratory infection
Is an adenosine nucleoside triphosphate analogue, interfering with the action of viral RNA-dependent RNA polymerase.
It is classified as a direct-acting antiviral agent SARS-CoV-2 (COVID-19) infections.

Question 32

What method is used for choosing rational treatment in selected patients?

Answer 32

genotypic analysis