Zyrtec Interactions
Antimuscarinics
Anxiolytics, Sedatives, and Hypnotics
- Buprenorphine
- Butorphanol
- Dronabinol, THC
- Entacapone
- Ethanol
General Anesthetics
Monoamine oxidase inhibitors (MAOIs)
- Nalbuphine
Opiate agonists
- Pentazocine
Phenothiazines
Sedating H1-blockers
- Theophylline, Aminophylline
- Tolcapone
- Tramadol
Tricyclic antidepressants
Zyrtec Interactions
MAOIs may prolong and intensify the anticholinergic effects of antihistamines. Although the anticholinergic activity of MAOIs is minimal; anticholinergic effects sometimes occur. It is recommended that the concurrent use of MAOIs with drugs possessing anticholinergic activity be avoided, especially atropine and scopolamine, since their effects and those of other anticholinergic drugs are potentiated and may become severe. Most manufacturers recommend that H1-antagonists not be used within two weeks of therapy with a MAOI.
Cetirizine undergoes minimal hepatic metabolism and excretion is largely as unchanged drug. Hence, the potential for drug interactions appears to be small. No clinically important drug interactions have been noted with azithromycin, erythromycin, ketoconazole or pseudoephedrine in adults. In addition, cimetidine does not alter the pharmacokinetics of cetirizine. No clinically significant interactions occurred when cetirizine was coadministered with a low dose (i.e., 400 mg PO once daily for 3 days) of theophylline; although, cetirizine clearance was slightly (16%) reduced. Per the manufacturer, it is possible that larger theophylline doses could have a greater effect on cetirizine pharmacokinetics. The disposition of theophylline is unaltered by cetirizine administration.
Cetirizine adds to the effect that ethanol has on CNS depression, but it apparently does not potentiate the effects of ethanol. Additive drowsiness may occur if cetirizine is administered with other drugs that depress the CNS. Cetirizine should be used with caution with barbiturates, benzodiazepines, buprenorphine, butorphanol, dronabinol, THC, entacapone, general anesthetics, haloperidol, nalbuphine, opiate agonists, pentazocine, pramipexole, risperidone, ropinirole, tolcapone, tramadol, tricyclic antidepressants or any other anxiolytics, sedatives, and hypnotics that depress the CNS.
Cetirizine has little effect on muscarinic, alpha-adrenergic, dopamine D2, or serotonin 5-HT2 receptors. Additive anticholinergic effects should not normally be a problem. However, dry mouth and drowsiness were more common in patients receiving cetirizine vs. placebo. Due to the duplicative and additive nature of the pharmacology of cetirizine, concurrent use of sedating H1-blockers is not recommended.
Cetirizine has little effect on muscarinic, alpha-adrenergic, dopamine D2, or serotonin 5-HT2 receptors. Additive anticholinergic effects should not normally be a problem. However, dry mouth and drowsiness were more common in patients receiving cetirizine vs. placebo, and caution may be necessary during concomitant use of cetirizine with the antimuscarinics or phenothiazines.
[ Last revised: 7/27/2004 6:34:00 PM ]
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