Viral Hepatitis

Question 1

Antiviral agents used to treat viral hepatitis include:

Answer 1

1. Nucleoside Analogs; Ribavirin

2. Interferon (IFN); Pegylated IFN-α 2a

Question 2

Therapeutic uses of ribavirin:

Answer 2

Guanosine nucleoside analog prodrug

• has broad spectrum against DNA and RNA viruses
• used primarily in combination with alpha-interpersonal to treat hepatitis C
• used as aerosol for treatment of RSV “human respiratory syncytial virus”

Question 3

————- is a major causes of lower respiratory tract infections in infants and children:

Answer 3

human respiratory syncytial virus RSV

Question 4

Pharmacokinetics of ribavirin:

Answer 4

• used orally and well absorbed by GIT
• given IV and by aerosol inhalation
• metabolized by liver and excreted in urine

Question 5

M.O.A of Ribavirin:

Answer 5

1) Initially, ribavirin is phosphorylated to mono-, di-, and triphosphate (active) by host cell kinases.
- monophosphate > inhibit ionosine monophosphate (IMP) dehydrogenase > decrease the synthesis of guanine nucleotides and depletion of GTP.

• Triphosphate inhibit viral RNA polymerase .

Question 6

AEs of ribavirin:

Answer 6

• Bacterial pneumonia and hypotension

- upper airway irritation (aerosol inhalation)

Question 7

Contraindications of ribavirin:

Answer 7

Pregnancy; teratogenic (pregnancy category X)

Question 8

Why we don’t use IFN alpha alone to treat hepatitis?

Answer 8

Because it has short half life 6 hours.
So we attach interferons alpha to polyethylene glycol which provide a protection against enzymatic degradation and increase duration of action into 48 hours half life (once-per-week dosing)

Question 9

Therapeutic uses of Pegylated IFN-α 2a:

Answer 9

• SC or IM to treat chronic hepatitis B & C (3 MU 3times weekly for 6-12 months)
• treat genital warts caused by human papilloma virus (HPV) (direct injection of pegylated IFN-alpha 2a into each lesion 3 times weekly for 3 weeks)

Question 10

Pharmacokinetics of pegylated IFN-alpha a2:

Answer 10

Metabolized by liver and excreted in urine.

Question 11

M.O.A of pegylated IFN alpha 2a:

Answer 11

It binds to its receptors located in Immune cells:

• enhance Ag presentation and stimulate immune system.
• increase expression of proteins that interfere with viral replication.
• inhibit viral protein synthesis, maturation, and release of progeny virions.

Question 12

AEs of pegylated IFN-alpha 2a:

Answer 12

• Flu-like syndrome
• alopecia
• impotence
• convulsion

Question 13

Contraindications of pegylated IFN-alpha 2a:

Answer 13

CVD (cardiovascular disease)
Seizure
Severe renal disease
Neonates and infants