Case no. | Suspected Drugs | Mechanisms | Description |
---|---|---|---|
1 | Thioridazine | Additive CNS and respiratory depression | A 38-year-old man was diagnosed with drug-induced psychotic disorder with hallucinations and started on thioridazine, flunitrazepam, and trihexyphenidyl for three months. He then experienced anxiety causing hyperventilation, and was consequently treated with midazolam and oxazolam. |
2 | Chlorpromazine | Additive CNS and respiratory depression | A 31-year-old woman was started on chlorpromazine for insomnia. After three months, she was diagnosed with hyperventilation and tachycardia, which may have been a result of methadone or a methadone-chlorpromazine interaction. |
3 | Tramadol | May result in withdrawal symptoms | A 48-year-old man was started on tramadol for a month. He then felt anxious, which may have been caused by a methadone-tramadol interaction. Upon discontinuing tramadol, no other symptoms related to anxiety persisted. |
 | Dexamethasone | CYP3A4 strong inducer | This man was started on dexamethasone for intracranial injury. After coadministering methadone with dexamethasone for a month, he started to feel anxious. |
4 | Tramadol | May result in withdrawal symptoms | A 48-year-old man was prescribed tramadol for a month for fractures of the tibia and fibula. Then, he developed a depressive mood, which may be owing to a methadone-tramadol interaction. |
5 | Paroxetine | CYP2B6 moderate inhibitor | A 38-year-old man was diagnosed with depression and started on paroxetine for several months. When methadone was coadministered with paroxetine, an anxious feeling persisted. |
6 | Ketoconazole | CYP3A4 strong inhibitor | A 41-year-old man's foot was infected with mycoses and was started on ketoconazole for two months. He was then diagnosed with angina pectoris, which may be due to a methadone-ketoconazole interaction. Upon stopping ketoconazole, he did not experience any symptoms related to angina. |