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:
When these two medicines are taken together, your body may not process your pain medicine properly.
What might happen:
If you take these medicines together for a long time, or if your dose of meperidine is increased, you may have toxic effects from meperidine, such as drowsiness, slurred speech, or seizures.
What you should do about this interaction:
Talk to your healthcare professionals (e.g. doctor or pharmacist) about taking these two medicines together. If you need to be taking a narcotic pain medicine for a long time, or if your meperidine stops working as well and you need a larger dose, your doctor may want to change your pain medicine. Your healthcare professionals may already be aware of this drug interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.
1.Norvir (ritonavir) US prescribing information. Abbott Laboratories March, 2015.
2.Piscitelli SC, Kress DR, Bertz RJ, Pau A, Davey R. The effect of ritonavir on the pharmacokinetics of meperidine and normeperidine. Pharmacotherapy 2000 May;20(5):549-53.
3.Demerol (meperidine hydrochloride) US prescribing information. Sanofi-Synthelabo, Inc. October, 2011.