Posology : מינונים

4.2   Posology and method of administration

Ritonavir should be administered by physicians who are experienced in the treatment of HIV infection.
Ritonavir film-coated tablets are administered orally and should be ingested with food (see section 5.2).

Norvir film-coated tablets should be swallowed whole and not chewed, broken or crushed.

Posology
Ritonavir dosed as a pharmacokinetic enhancer

When ritonavir is used as a pharmacokinetic enhancer with other protease inhibitors the prescribing information for the particular protease inhibitor must be consulted.

The following HIV-1 protease inhibitors have been approved for use with ritonavir as a pharmacokinetic enhancer at the noted doses.

Adults

Amprenavir 600 mg twice daily with ritonavir 100 mg twice daily.
Atazanavir 300 mg once daily with ritonavir 100 mg once daily.

Fosamprenavir 700 mg twice daily with ritonavir 100 mg twice daily.
Lopinavir co-formulated with ritonavir (lopinavir/ritonavir) 400 mg/100 mg or 800 mg/200 mg.

Saquinavir 1000 mg twice daily with ritonavir 100 mg twice daily in ART experienced patients. Initiate treatment with saquinavir 500 mg twice daily with ritonavir 100 mg twice daily for the first 7 days, then saquinavir 1000 mg twice daily with ritonavir 100 mg twice daily in ART-naïve patients.

Tipranavir 500 mg twice daily with ritonavir 200 mg twice daily. Tipranavir with ritonavir should not be used in treatment-naïve patients.

Darunavir 600 mg twice daily with ritonavir 100 mg twice daily in antiretroviral treatment (ART) experienced patients. Darunavir 800 mg once daily with ritonavir 100 mg once daily may be used in some ART experienced patients. Refer to the darunavir prescribing information for further information on once daily dosing in ART experienced patients.

Darunavir 800mg once daily with ritonavir 100 mg once daily in ART-naïve patients.

Children and adolescents
Ritonavir is recommended for children 2 years of age and older. For further dosage recommendations, refer to the product information of other Protease Inhibitors approved for co-administration with ritonavir.

Special populations

Renal impairment
As ritonavir is primarily metabolised by the liver, ritonavir may be appropriate for use with caution as a pharmacokinetic enhancer in patients with renal insufficiency depending on the specific protease inhibitor with which it is co-administered. However, since the renal clearance of ritonavir is negligible, the decrease in the total body clearance is not expected in patients with renal impairment. For specific dosing information in patients with renal impairment, refer to the prescribing information of the co-administered protease inhibitor.

Hepatic impairment

Ritonavir should not be given as a pharmacokinetic enhancer to patients with decompensated liver disease, (see section 4.3). In the absence of pharmacokinetic studies in patients with stable severe hepatic impairment (Child Pugh Grade C) without decompensation, caution should be exercised when ritonavir is used as a pharmacokinetic enhancer as increased levels of the co-administered PI may occur. Specific recommendations for use of ritonavir as a pharmacokinetic enhancer in patients with hepatic impairment are dependent on the protease inhibitor with which it is co-administered. The prescribing information of the co- administered PI should be reviewed for specific dosing information in this patient population.

Ritonavir dosed as an antiretroviral agent

Adults
The recommended dose of Norvir film-coated tablets is 600 mg (6 tablets) twice daily (total of 1200 mg per day) by mouth.

Gradually increasing the dose of ritonavir when initiating therapy may help to improve tolerance. Treatment should be initiated at 300 mg (3 tablets) twice daily for a period of three days and increased by 100 mg (1 tablet) twice daily increments up to 600 mg twice daily over a period of no longer than 14 days. Patients should not remain on 300 mg twice daily for more than 3 days.

Children and adolescents (2 years of age and above):

The recommended dosage of Norvir in children is 350 mg/m2 by mouth twice daily and should not exceed 600 mg twice daily. Norvir should be started at 250 mg/m2 and increased at 2 to 3 day intervals by 50 mg/m2 twice daily.

Norvir is not recommended in children below 2 years of age due to lack of data on safety and efficacy.

Special populations
Elderly

Pharmacokinetic data indicated that no dose adjustment is necessary for elderly patients (see section 5.2).

Renal impairment
Currently, there are no data specific to this patient population and therefore specific dosage recommendations cannot be made. The renal clearance of ritonavir is negligible therefore; a decrease in the total body clearance is not expected in patients with renal impairment. Because ritonavir is highly protein bound it is unlikely that it will be significantly removed by haemodialysis or peritoneal dialysis.

Hepatic impairment

Ritonavir is principally metabolised and eliminated by the liver. Pharmacokinetic data indicate that no dose adjustment is necessary in patients with mild to moderate hepatic impairment (see section 5.2). Ritonavir must not be given to patients with severe hepatic impairment (see section 4.3).

Paediatric population

The safety and efficacy of Norvir in children aged below 2 years has not been established. Currently available data are described in sections 5.1 and 5.2 but no recommendation on a posology can be made.