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| __NOTOC__
| | #REDIRECT [[Mexiletine#Drug Interactions]] |
| {{Mexiletine}}
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| {{CMG}}; {{AE}} {{SS}}
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| ==Drug Interactions==
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| Since mexiletine hydrochloride is a substrate for the metabolic pathways involving CYP2D6 and CYP1A2 enzymes, inhibition or induction of either of these enzymes would be expected to alter mexiletine plasma concentrations. In a formal, single-dose interaction study (n = 6 males) the clearance of mexiletine was decreased by 38% following the coadministration of fluvoxamine, an inhibitor of CYP1A2. In another formal study (n = 8 extensive and n = 7 poor metabolizers of CYP2D6), coadministration of [[propafenone]] did not alter the kinetics of mexiletine in the poor CYP2D6 metabolizer group. However, the metabolic clearance of mexiletine in the extensive metabolizer phenotype decreased by about 70% making the poor and extensive metabolizer groups indistinguishable. In this crossover steady state study, the pharmacokinetics of [[propafenone ]]were unaffected in either phenotype by the coadministration of mexiletine. Addition of mexiletine to [[propafenone ]]did not lead to further electrocardiographic parameters changes of QRS, QTc, RR, and PR intervals than [[propafenone ]]alone. When concomitant administration of either of these two drugs is initiated, the dose of mexiletine should be slowly titrated to desired effect.
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| In a large compassionate use program mexiletine has been used concurrently with commonly employed [[antianginal]], [[antihypertensive]], and [[anticoagulant]] drugs without observed interactions. A variety of [[antiarrhythmics]] such as [[quinidine]] or [[propranolol]] were also added, sometimes with improved control of ventricular ectopy. When phenytoin or other hepatic enzyme inducers such as [[rifampin]] and [[phenobarbital]] have been taken concurrently with mexiletine, lowered mexiletine plasma levels have been reported. Monitoring of mexiletine plasma levels is recommended during such concurrent use to avoid ineffective therapy.
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| In a formal study, benzodiazepines were shown not to affect mexiletine plasma concentrations. ECG intervals (PR, QRS, and QT) were not affected by concurrent mexiletine and [[digoxin]], [[diuretics]], or [[propranolol]].
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| Concurrent administration of [[cimetidine]] and mexiletine has been reported to increase, decrease, or leave unchanged mexiletine plasma levels; therefore patients should be followed carefully during concurrent therapy.
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| Mexiletine does not alter serum [[digoxin]] levels but magnesium-aluminum hydroxide, when used to treat gastrointestinal symptoms due to mexiletine, has been reported to lower serum [[digoxin]] levels.
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| Concurrent use of mexiletine and theophylline may lead to increased plasma theophylline levels. One controlled study in eight normal subjects showed a 72% mean increase (range
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| 35 to 136%) in plasma [[theophylline ]]levels. This increase was observed at the first test point which was the second day after starting mexiletine. [[theophylline ]]plasma levels returned to pre-mexiletine values within 48 hours after discontinuing mexiletine. If mexiletine and [[theophylline ]]are to be used concurrently, [[theophylline ]]blood levels should be monitored, particularly when the mexiletine dose is changed. An appropriate adjustment in [[theophylline ]]dose should be considered.
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| Additionally, in one controlled study in five normal subjects and seven patients, the clearance of caffeine was decreased 50% following the administration of mexiletine.
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| <ref name="dailymed.nlm.nih.gov">{{Cite web | last = | first = | title = MEXILETINE HYDROCHLORIDE CAPSULE [TEVA PHARMACEUTICALS USA INC] | url = http://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=693da40b-26d4-40d6-87d1-158e256f40ab | publisher = | date = | accessdate = 3 March 2014 }}</ref>
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| ==References==
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| {{Reflist}}
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| {{Antiarrhythmic agents}}
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| [[Category:Sodium channel blockers]]
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| [[Category:Phenol ethers]]
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| [[Category:Cardiovascular Drugs]]
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| [[Category:Drugs]]
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