Drug Interaction Report

Ritonavir may increase the blood levels and effects of tolterodine. You may need a dose adjustment or more frequent monitoring by your doctor to safely use both medications. Contact your doctor if your condition changes or you experience increased side effects. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Ritonavir may increase the blood levels and effects of tenofovir. This can increase the risk of side effects including serious ones like kidney or liver damage and a condition known as lactic acidosis, which is a buildup of lactic acid in the blood. You should seek immediate medical attention if you develop symptoms of these conditions. Symptoms of kidney damage may include swelling, weight gain, shortness of breath, drowsiness, confusion, mood changes, increased thirst, loss of appetite, nausea, vomiting, pain in your lower back, and urinating more or less than usual or not at all. Symptoms of liver damage may include fever, chills, joint pain or swelling, unusual bleeding or bruising, skin rash, itching, loss of appetite, fatigue, nausea, vomiting, dark colored urine, and/or yellowing of the skin or eyes. Symptoms of lactic acidosis may include fatigue, unusual muscle pain, difficulty breathing, stomach pain, nausea, vomiting, lightheadedness, dizziness, and a fast or irregular heartbeat. You may need a dose adjustment or more frequent monitoring by your doctor to safely use both medications. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Consumer information for this interaction is not currently available.

GENERALLY AVOID: Lopinavir in combination with ritonavir may cause dose-related prolongation of the QT interval. Theoretically, coadministration with other agents that can prolong the QT interval may result in additive effects and increased risk of ventricular arrhythmias including torsade de pointes and sudden death. In a study of 39 healthy adults who were administered lopinavir-ritonavir at a therapeutic dosage of 400 mg-100 mg twice daily and a supratherapeutic dosage of 800 mg-200 mg twice daily, the maximum mean time-matched difference in QTcF interval from placebo (after baseline correction) was 5.3 msec for the lower dosage and 15.2 msec for the supratherapeutic dosage in the 12 hours post-dose on treatment day 3 when exposures were approximately 1.5 and 3-fold higher, respectively, than those observed with recommended once-daily or twice-daily dosages of lopinavir-ritonavir at steady state. No subject experienced an increase in QTcF greater than 60 msec from baseline or a QTcF interval exceeding the potentially clinically relevant threshold of 500 msec. There have been cases of QT interval prolongation and torsade de pointes arrhythmia during postmarketing use of lopinavir-ritonavir, although causality could not be established. In general, the risk of an individual agent or a combination of agents causing ventricular arrhythmia in association with QT prolongation is largely unpredictable but may be increased by certain underlying risk factors such as congenital long QT syndrome, cardiac disease, and electrolyte disturbances (e.g., hypokalemia, hypomagnesemia). In addition, the extent of drug-induced QT prolongation is dependent on the particular drug(s) involved and dosage(s) of the drug(s).

MANAGEMENT: Coadministration of lopinavir-ritonavir with other drugs that can prolong the QT interval should generally be avoided. Patients treated with any medication that can cause QT prolongation should be advised to seek prompt medical attention if they experience symptoms that could indicate the occurrence of torsade de pointes such as dizziness, lightheadedness, fainting, palpitation, irregular heart rhythm, shortness of breath, or syncope.

Lopinavir may increase the blood levels and effects of tenofovir. This can increase the risk of side effects including serious ones like kidney or liver damage and a condition known as lactic acidosis, which is a buildup of lactic acid in the blood. You should seek immediate medical attention if you develop symptoms of these conditions. Symptoms of kidney damage may include swelling, weight gain, shortness of breath, drowsiness, confusion, mood changes, increased thirst, loss of appetite, nausea, vomiting, pain in your lower back, and urinating more or less than usual or not at all. Symptoms of liver damage may include fever, chills, joint pain or swelling, unusual bleeding or bruising, skin rash, itching, loss of appetite, fatigue, nausea, vomiting, dark colored urine, and/or yellowing of the skin or eyes. Symptoms of lactic acidosis may include fatigue, unusual muscle pain, difficulty breathing, stomach pain, nausea, vomiting, lightheadedness, dizziness, and a fast or irregular heartbeat. You may need a dose adjustment or more frequent monitoring by your doctor to safely use both medications. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Ritonavir should be taken with food to lessen gastrointestinal side effects. It is important that you take this medication exactly as prescribed by your doctor. Do not change your treatment or stop treatment without first talking to your doctor.

Food may affect the absorption of lopinavir-ritonavir (brand name Kaletra) depending on whether you are taking the oral solution or the tablet. The oral solution should be taken with food to enhance absorption and help it work better. The tablet formulation can be take with or without food. Talk to your doctor or pharmacist if you have questions on how to take this or other medications you are prescribed. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Information for this minor interaction is available on the professional version.