Drug Interaction Report

Using ketamine together with midazolam may increase side effects such as dizziness, drowsiness, confusion, difficulty concentrating, excessive sedation, and respiratory depression. Some people, especially the elderly, may also experience impairment in thinking, judgment, and motor coordination. You should avoid or limit the use of alcohol while being treated with ketamine. Also avoid activities requiring mental alertness such as driving, operating hazardous machinery, or engaging in potentially hazardous activities until you know how the medications affect you. Talk to your doctor if you have any questions or concerns. 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.

MONITOR: Central nervous system- and/or respiratory-depressant effects may be additively or synergistically increased in patients taking multiple drugs that cause these effects, especially in elderly or debilitated patients. Sedation and impairment of attention, judgment, thinking, and psychomotor skills may increase.

MANAGEMENT: During concomitant use of these drugs, patients should be monitored for potentially excessive or prolonged CNS and respiratory depression. Cautious dosage titration may be required, particularly at treatment initiation. Ambulatory patients should be counseled to avoid hazardous activities requiring mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.

Consumer information for this interaction is not currently available.

MONITOR: Tolterodine 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 QTc study conducted in 48 healthy subjects, the mean change in QTc interval from baseline to peak tolterodine concentration was 5 msec for immediate release tolterodine 2 mg twice daily. At twice the therapeutic dosage of tolterodine, 4 mg twice daily, the mean change in QTc interval from baseline to peak tolterodine concentration was 11.8 msec. The QTc interval increases in poor metabolizers of CYP450 2D6 administered tolterodine 2 mg twice daily were comparable to those observed in extensive metabolizers of CYP450 2D6 administered 4 mg twice daily in a pharmacokinetic/pharmacodynamic model. 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: Caution is recommended if tolterodine is used in combination with other drugs that can prolong the QT interval. Clinical and laboratory monitoring, including QTc interval and serum electrolytes, is advised. Patients should have regular ECGs and be monitored for arrhythmias when the QTc interval is prolonged. If the QTc interval becomes markedly prolonged or symptoms of arrhythmia occur, drug discontinuation should be considered. Patients 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. Patients should be advised to notify their physician if they experience new or worsening side effects of tolterodine including severe blurry vision, difficulty urinating, dry mouth, headache, drowsiness, dizziness, or GI upset.

Using ketamine together with ethanol (alcohol) may increase side effects such as dizziness, drowsiness, confusion, difficulty concentrating, excessive sedation, and respiratory depression. Some people, especially the elderly, may also experience impairment in thinking, judgment, and motor coordination. You should avoid or limit the use of alcohol while being treated with ketamine. Also avoid activities requiring mental alertness such as driving, operating hazardous machinery, or engaging in potentially hazardous activities until you know how the medications affect you. Talk to your doctor if you have any questions or concerns. 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.

Alcohol can increase the nervous system side effects of ketamine such as dizziness, drowsiness, and difficulty concentrating. Some people may also experience impairment in thinking and judgment. You should not drink alcohol during treatment with ketamine. If you have received ketamine for anesthesia, you should avoid activities requiring mental alertness such as driving or operating hazardous machinery for at least 24 hours and until you know how the medication affects you. If you are taking ketamine orally, you should also avoid the consumption of grapefruit or grapefruit juice, which can significantly increase blood levels and side effects of the medication. Talk to your doctor if you have any questions or concerns. 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.

Grapefruit and grapefruit juice may interact with midazolam and lead to potentially dangerous side effects. Discuss the use of grapefruit products with your doctor. Do not increase or decrease the amount of grapefruit products in your diet without first talking to your doctor. Do not drink alcohol while taking midazolam. This medication can increase the effects of alcohol. You may feel more drowsy, dizzy, or tired if you take midazolam with alcohol. Talk to your doctor or pharmacist if you have any questions or concerns.