Lorazepam Interactions
Anxiolytics, Sedatives, and Hypnotics
- Aripiprazole
Barbiturates
- Buprenorphine
- Butorphanol
- Caffeine
- Clozapine
- Dronabinol, THC
- Entacapone
- Ethanol
- Flumazenil
General Anesthetics
- Green Tea
- Guarana
- Kava Kava, Piper methysticum
- Levodopa
- Melatonin
- Nabilone
- Nalbuphine
- Olanzapine
Opiate agonists
Oral contraceptives
- Pentazocine
Phenothiazines
- Pregabalin
- Probenecid
- Pyrimethamine
Radiopaque Contrast Agents
Sedating H1-blockers
- Sodium Phosphate Monobasic Monohydrate; Sodium Phosphate Dibasic Anhydrous
- Theophylline, Aminophylline
- Tolcapone
- Tramadol
Tricyclic antidepressants
- Valerian, Valeriana officinalis
- Valproic Acid, Divalproex Sodium
Lorazepam Interactions
Probenecid has been shown to decrease lorazepam clearance by about 50% and increase its elimination half-life. Patients receiving lorazepam should be monitored for signs of altered benzodiazepine response when probenecid is initiated or discontinued.
Benzodiazepines should be combined cautiously with clozapine because they could cause additive CNS depressant effects. Severe confusion, hypotension and respiratory depression have occurred rarely in those patients receiving clozapine concurrently or following benzodiazepine therapy. A single case report is noted where the addition of clozapine to maintenance therapy with clonazepam lead to somnolence, confusion, disorientation, and ataxia. The symptoms cleared after clonazepam was discontinued. In patients receiving concomitant clozapine, the starting doses of the benzodiazepine should be approximately one-half of the usual dose until experience with the patient has been gained.
The manufacturer of olanzapine (Zyprexa® ) recommends that concurrent use of intramuscular olanzapine and parenteral benzodiazepines be avoided if possible since safety of the combination has not been studied. Potential adverse effects of the combination include excess sedation and/or cardiorespiratory depression.
The manufacturer of aripiprazole (Abilify® ) injection recommends that patients be monitored for sedation and orthostatic hypotension during concurrent use of a parenteral benzodiazepine and intramuscular aripiprazole. Potential adverse effects of the combination include excess sedation and/or cardiorespiratory depression.
Concomitant administration of lorazepam with CNS-depressant drugs , including opiate agonists, buprenorphine, butorphanol, nalbuphine, pentazocine, phenothiazines, barbiturates , dronabinol, THC , nabilone , entacapone , ethanol , sedating H1-blockers, general anesthetics, pregabalin , tolcapone, tramadol, tricyclic antidepressants, or other anxiolytics, sedatives, and hypnotics, can potentiate the CNS effects (i.e., increased sedation or respiratory depression) of either agent.
Oral contraceptives can decrease the effects of oxazepam (and possibly lorazepam) because oral contraceptives enhance glucuronidation, thereby decreasing serum concentrations of concomitantly administered benzodiazepines that undergo glucuronidation. Patients receiving oral contraceptive therapy should be observed for evidence of decreased response to lorazepam.
Flumazenil and benzodiazepines are pharmacological opposites. Flumazenil is specifically used to reverse the actions of benzodiazepines. Clinicians should note that the duration of action for some benzodiazepines may be much longer than that of flumazenil and repeat doses of flumazenil may be necessary.
It appears prudent to recommend caution when lorazepam is prescribed in conjunction with melatonin. In animal studies, melatonin has been shown to increase benzodiazepine binding to receptor sites, and this may result in clinically significant drug interactions. Case reports exist of concomitant benzodiazepine and melatonin use in humans; the cases resulted in lethargy, short-term amnestic responses, or prolonged benzodiazepine activity. These apparent interactions could have been the result of a pharmacokinetic or pharmacodynamic enhancement of benzodiazepine activity by melatonin.
The German Commission E warns that any substances that act on the CNS, including psychotropic agents such as lorazepam, may interact with kava kava. Patients receiving benzodiazepine therapy should avoid concomitant administration of kava kava. Patients should discuss the use of herbal supplements with their health care professional prior to consuming kava kava and should not abruptly stop taking their prescribed medications.
Any substances that act on the CNS, including benzodiazepines, may interact with valerian, Valeriana officinalis. These interactions are probably pharmacodynamic in nature. Patients taking lorazepam should avoid concomitant administration of valerian.
Theophylline has been reported to counteract the pharmacodynamic effects (e.g., sedative and anxiolytic effects) of diazepam. A proposed mechanism is competitive binding of theophylline to adenosine receptors in the brain. Whether a similar interaction occurs with other benzodiazepines is not known. If theophylline therapy is initiated or discontinued, monitor the clinical response to benzodiazepines.
Prior to general anesthesia or conscious sedation, levodopa or carbidopa; levodopa therapy may be continued as long as the patient is permitted to take oral medication. If levodopa-based therapy is interrupted temporarily, the patient should be observed for signs of neuroleptic malignant syndrome, and the usual dosage should be administered as soon as the patient is able to take oral medication.
Patients taking benzodiazepines for insomnia should not use caffeine-containing products such as guarana or beverages (e.g., coffee, green tea, other teas, or colas) prior to going to bed as these products may antagonize the sedative effects of the benzodiazepine.
Valproic acid, divalproex sodium has been reported to increase lorazepam peak plasma concentrations and the AUC by 8% and 20%, respectively. In this study, concurrent valproic therapy did not alter sedation scores. This interaction is attributed to inhibition of hepatic glucuronidation of lorazepam by valproate.
Mild hepatotoxicity has been reported when pyrimethamine was coadministered with lorazepam.
The use of intrathecal radiopaque contrast agents is associated with a risk of seizures. Patients should be instructed to continue using benzodiazepines during procedures or exams that require the use of intrathecal radiopaque contrast agents as abrupt discontinuation of benzodiazepines may also increase seizure risk.
Sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous should be used with caution in patients at a higher risk of seizures. The abrupt withdrawal of benzodiazepines may increase the risk of seizures. There have been reports of tonic-clonic seizures and/or loss of consciousness in patients who are undergoing withdrawal from benzodiazepines.
[ Last revised: 10/19/2006 3:14:00 PM ]
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