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Norvir Soft Gelatin

Interactions

Methadone/Nelfinavir; Ritonavir; Telaprevir

This information is generalized and not intended as specific medical advice. Consult your healthcare professional before taking or discontinuing any drug or commencing any course of treatment.

Medical warning:

Moderate. These medicines may cause some risk when taken together. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.

How the interaction occurs:

Nelfinavir, ritonavir, and telaprevir may speed up how quickly your body processes methadone.

What might happen:

The amount of methadone in your blood may decrease and it may not work as well.

What you should do about this interaction:

Let your healthcare professionals (e.g. doctor or pharmacist) know that you are taking these medicines together. If you experience nausea, vomiting, stomach pain, diarrhea, irritability, sleep disturbances, other withdrawal symptoms, or if your methadone is not controlling your pain, contact your healthcare professionals (e.g. doctor or pharmacist). Your doctor may want to adjust the dose of your medicine.Your healthcare professionals may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.

References:

1.Beauverie P, Taburet AM, Dessalles MC, Furlan V, Touzeau D. Therapeutic drug monitoring of methadone in HIV-infected patients receiving protease inhibitors. AIDS 1998 Dec 24;12(18):2510-1.

2.Kharasch ED, Walker A, Whittington D, Hoffer C, Bedynek PS. Methadone metabolism and clearance are induced by nelfinavir despite inhibition of cytochrome P4503A (CYP3A) activity. Drug Alcohol Depend 2009 May 1; 101(3):158-68.

3.Marco A, Deig E, Cadafalch J, Fuster M, Valls I, Pedrol E. Clinical and pharmacokinetic interactions between methadone and nelfinavir (Nemesia study). Med Clin (Barc) 2006 Jun 10;127(2):47-50.

4.Hsyu PH, Lillibridge J, Daniels E, Kerr BM. Pharmacokinetic interaction of nelfinavir and methadone in intravenous drug users. Biopharm Drug Dispos 2006 Mar;27(2):61-8.

5.Kharasch ED, Bedynek PS, Park S, Whittington D, Walker A, Hoffer C. Mechanism of ritonavir changes in methadone pharmacokinetics and pharmacodynamics: I. Evidence against CYP3A mediation of methadone clearance. Clin Pharmacol Ther 2008 Oct;84(4):497-505.

6.Jimenez-Lerma JM, Iraurgi I. Potential opiate withdrawal syndrome after ritonavir administration in a patient treated with methadone. Rev Clin Esp 1999 Mar;199(3):188-9.

7.Incivek (telaprevir) US prescribing information. Vertex Pharmaceuticals Incorporated October, 2013.

Selected from data included with permission and copyrighted by First Databank, Inc. This copyrighted material has been downloaded from a licensed data provider and is not for distribution, expect as may be authorized by the applicable terms of use.

CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgment of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects, nor should it be construed to indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.

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