Anti-Infectives - Antivirals

Question 1

Give 1 example of an antiviral drug.

Answer 1

Aciclovir

Question 2

Describe the mechanism of aciclovir. (3)

Answer 2

1. Aciclovir is a guanosine derivative, which is converted to aciclovir triphosphate by infected host cells
2. Aciclovir triphosphate then inhibits DNA polymerase, terminating the nucleotide chain
3. This inhibits viral DNA replication

Question 3

List 2 indications for aciclovir.

Answer 3

Herpes simplex

Varicella zoster

Question 4

List 3 side effects of low dose aciclovir.

List 2 side effects of high dose aciclovir.

Answer 4

LOW DOSE:
Nausea
Vomiting
Local inflammation at infusion site (if IV)

HIGH DOSE:
Renal tubular crystalosis
Seizures

Question 5

Describe the important pharmacokinetics/dynamics of aciclovir. (3)

Answer 5

Administration: oral, IV or topical
Good CSF penetration
Renal excretion (dose adjustment needed in kidney impairment)

Question 6

What would you tell the patient when prescribing aciclovir? (2)

Answer 6

Multiple/repeat doses may be needed in immunosuppressed patients
Recurrent infection may prompt HIV testing

Question 7

Apart from aciclovir, what is the other main group of antivirals?

Give 3 examples.

Answer 7

Neuraminidase inhibitors

Oseltamivir (Tamiflu)
Peramivir (Rapivab)
Zanamivir (Relenza)

Question 8

Describe the mechanism of action of neuraminidase inhibitors. (2)

Answer 8

1. Inhibit action of neuraminidase, which cleaves sialic acid groups from glycoproteins
2. This inhibits viral budding and viral replication

Question 9

List 1 indication for neuraminidase inhibitors.

Answer 9

Influenza

Question 10

List 2 side effects of neuraminidase inhibitors.

Answer 10

GI toxicity

Neuropsychiatric symptoms

Question 11

Give 3 examples of nucleoside reverse transcription inhibitors.

What are these used for?

Answer 11

Abacavir
Didanosine
Tenofovir

Used for: HIV

Question 12

List 6 side effects of nucleoside reverse transcriptase inhibitors.

Answer 12

GI toxicity
CNS effects
MSK effects
Blood disorders
Liver/pancreas effects
Lipodystrophy

Question 13

Apart from nucleoside reverse transcriptase inhibitors, list 5 other types of antivirals which can be used in HIV.

Answer 13

Non-nucleoside reverse transcriptase inhibitors
Protease inhibitors
Inhibitors of HIV fusion with host cells
Integrase inhibitors
Chemokine receptor antagonist (CCR5)