|English: Synthesis of methadone Deutsch: Synthese von Methadon (Photo credit: Wikipedia)|
|structural formula of Verapamil (Photo credit: Wikipedia)|
"Methadone appears to have a molecular structure similar to that of verapamil and may exhibit similar cardiac properties, such as calcium channel blockade. One study demonstrated that methadone, unlike morphine, significantly lowered heart rate in rats (p<0 .05="" span="">0>
10 Seyler DE, Borowitz JL, Maickel RP. Calcium channel blockade by certain opioids. Fundam Appl Toxicol 1983;3:536-42.
The potential of methadone to cause adverse effects similar to verapamil must be taken under consideration clinically in any patient taking methadone or is to start methadone.