Viekira Pak: Hepatitis C Drug Side Effects & Dosage

What is Viekira Pak? What is Viekira Pak used for?

Viekira Pak is a combination of drugs used to treat
patients with hepatitis C virus (HCV) genotype 1. It contains four medicines,
dasabuvir, ombitasvir, paritaprevir, and ritonavir. Viekira Pak belongs to a
class of drugs called direct-acting antiviral agents. Similar drugs include

boceprevir
(Victrelis),
sofosbuvir
(Sovaldi),
simeprevir
(Olysio),
telaprevir
(Incivek), and
ombitasvir, paritaprevir, ritonavir (Technivie).

Dasabuvir, ombitasvir, and paritaprevir are antivirals that work in three
different ways to help stop HCV from multiplying. They block the effect of
proteases which are enzymes that HCV uses for making new virus, leading to
reduced numbers of HCV copies in the body. Ombitasvir blocks HCV NS5A protease
while paritaprevir blocks HCV NS3/4A protease. Dasabuvir blocks a viral
structure called NS5B palm polymerase which is also needed for replication of
HCV. Ritonavir is not active against the HCV virus. It is used to increase blood
levels of paritaprevir by inhibiting the breakdown of paritaprevir.

In clinical studies Viekira Pak, with or without ribavirin (Rebetol) HCV was
cured in 95% to 100% of patients treated. Cure was defined as undetectable
levels of HCV in the blood 3 months after treatment. The FDA approved Viekira
Pak in December 2014.

What brand names are available for Viekira Pak?

Viekira Pak

Is Viekira Pak available as a generic drug?

Do I need a prescription for Viekira Pak?

Yes

What are the side effects of Viekira Pak?

The most common side effects of Viekira Pak when used with
ribavirin include

tiredness,
nausea,
itching,
skin reactions such as redness or
rash,
sleep problems
(insomnia), and
feeling weak.

The most common side effects of Viekira Pak when used without ribavirin
include

nausea,
itching, and
problems sleeping.

Other side effects include

allergic reactions,
anemia, and
increases in
liver
enzymes and bilirubin.

QUESTION

Hepatitis C virus causes an infection of the ______________.
See Answer

What is the dosage for Viekira Pak?

Viekira Pak is supplied in monthly cartons that contain enough
medicine for 28 days. Each daily dose pack contains four tablets: two 12.5/75/50
mg ombitasvir, paritaprevir, ritonavir tablets and two 250 mg dasabuvir tablets.
The recommended dose of Viekira Pak is two tablets containing ombitasvir,
paritaprevir, ritonavir in the morning and one dasabuvir tablet in the morning
and evening. Viekira Pak should be taken with meals.
Certain patients may also be treated with ribavirin. The dosage of ribavirin
is based on weight and is usually administered twice daily with food.
The recommended treatment regimen and duration of treatment for each type of
HCV infection is as follows:
- Patients with HCV genotype 1a without
  cirrhosis may be treated with Viekira Pak plus ribavirin for 12 weeks.
- Patients with HCV genotype 1a with cirrhosis
  may be treated with Viekira Pak plus ribavirin for 24 weeks. (Some patients who
  have had prior treatment with other drugs may be considered for a shorter
  treatment duration of 12 weeks.)
- Patients with HCV genotype 1b without
  cirrhosis may be treated with Viekira Pak for 12 weeks.
- Patients with HCV genotype 1b with cirrhosis
  may be treated with Viekira Pak plus ribavirin for 12 weeks.
No dosage adjustment is required in patients with mild liver impairment.
Viekira Pak is not recommended for patients with moderate liver impairment and
is contraindicated in patients with severe liver impairment.

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Which drugs or supplements interact with Viekira Pak?

Viekira Pak interacts with many drugs. The prescribing information should be
consulted for a complete list of drugs that interact with Viekira Pak. Viekira
Pak should not be used with the following medications:
Afluzosin hydrochloride (Uroxatral), a
medicine used to treat
benign prostate hyperplasia (BPH), due to the risk of
hypotension (low blood pressure).
Certain anti-seizure medications, including
carbamazepine (Tegretol),
phenytoin (Dilantin), and phenobarbital (Luminal), may
decrease the blood concentrations of Viekira Pak and reduce the effectiveness of
treatment.
Rifampin (Rifadin, Rimactane), a component of
many tuberculosis treatment regimens, may decrease the blood concentrations of
Viekira Pak, reducing the effectiveness of treatment.
Ergot derivatives which are used to treat
migraine headaches should not be used with Viekira Pak due to the risk of ergot
toxicity.
Combination birth control pills that contain
ethinyl
estradiol should be avoided due to the potential for liver damage.
St. John’s Wort may decrease the blood
concentrations of Viekira Pak, resulting in reduced effectiveness of treatment.
Commonly used
cholesterol lowering agents,
lovastatin (Mevacor) and
simvastatin (Zocor), should be avoided due to the risk
for serious
muscle pain and injury, including
rhabdomyolysis.
Combining Viekira Pak and pimozide (Orap) may
increase the risk for abnormal heart beats.
Combining
efavirenz (Sustiva) and Viekira Pak
may increase the risk of liver damage.
Combining Viekira Pak with
sildenafil
(Viagra, Revatio) and similar drugs may increase the risk of vision problems,
low blood pressure,
fainting, and
priapism (painful, long lasting erection).
Viekira Pak increases blood levels of
triazolam
(Halcion) and midazolam, leading to increased sedation and respiratory depression.

Is Viekira Pak safe to take if I’m pregnant or breastfeeding?

Viekira Pak has not been evaluated in pregnant women. Therefore,
Viekira Pak should be used during pregnancy only if the potential benefit
justifies the potential risk to the fetus.

When Viekira Pak is administered with ribavirin, the combination regimen
should not be used in pregnant women and in men who can father children.
Ribavirin is known to cause birth defects and should be avoided during
pregnancy.

There is an antiretroviral pregnancy registry that monitors the use of
products such as Viekira Pak in HCV/HIV-1 co-infected women. Patients are
advised to enroll in this program to help study and understand the safety of
antiretroviral therapy during pregnancy.

It is not known whether any of the drugs contained in Viekira Pak are excreted into human milk. Due to the lack of conclusive safety
data, Viekira Pak should be used cautiously in nursing mothers.

What else should I know about Viekira Pak?

What preparations of Viekira Pak are available?

Tablets: 12.5/75/50 mg ombitasvir, paritaprevir, ritonavir
co-packaged with 250 mg dasabuvir tablets.

How should I keep Viekira Pak stored?

Viekira Pak should be stored at room temperature between 15 C and 30
C (59 F and 86 F). Viekira Pak as well as all medicines should be kept out of
the reach of children and pets.