Ephedrine Entacapone

An interaction of ephedrine with entacapone, a specific, reversible, peripherally acting inhibitor of catechol-O-methyl transferase, has been reported (37). 

The effect of ephedrine, which is both a direct and indirect sjmpathomimetic, may have been enhanced by its not being metabolized by catechol-O-methyl transferase, becanse of the action of entacapone. 

Renfrew C, Dickson R, Schwab C. Severe hypertension following ephedrine administration in a patient receiving entacapone. Anesthesiology 2000 93(6) 1562. 

Clinically important, potentially hazardous interactions with amitriptyline, amoxapine, amphetamines, bupropion, citalopram, clomipramine, cyproheptadine, desipramine, dextroamphetamine, dextromethorphan, diethylpropion, dopamine, doxepin, entacapone, ephedra, ephedrine, epinephrine, fluoxetine, fluvoxamine, ginseng, imipramine, levodopa, mazindol, meperidine, methamphetamine, nefazodone, nortriptyline, paroxetine, phendimetrazine, phentermine, phenylephrine, pizotifen, propoxyphene, protriptyline, pseudoephedrine, rizatriptan, sertraline, sibutramine, sumatriptan, sympathomimetics, tramadol, tricyclic antidepressants, trimipramine, tryptophan, venlafaxine, zolmitriptan... 

A single case report describes severe hyperteusiou iu a patieut given entacapone and intravenous ephedrine. Tolcapone did not alter the effect of ephedrine in one study. 

A 76-year-old woman with Parkinson s disease taking levodopa/carbi-dopa and entacapone 200 mg five times daily, was given 3 mg of intravenous ephedrine during cataract surgery to correct a low blood pressure of 85/35 mmHg. Her blood pressure immediately rose to 225/125 mmHg. The patient needed several doses of hydralazine over the following 140 minutes before her blood pressure returned to normal. ... 

The single case report with entacapone and intravenous ephedrine appears to be the only evidence that COMT inhibitors could potentiate the effect of indirectly-acting sympathomimetics such as ephedrine. The manufacturer of tolcapone states that ephedrine and tolcapone ean be used concurrently. Nevertheless, some caution may be warranted with intravenous ephedrine. 

---