Hull and East Yorkshire Local Medical Committee

Wider context from the report

“Stuart died as a result of drug poisoning. However, there was no evidence of illicit drug use (other than cannabis which the Consultant Histopathologist confirmed had not played a part in the death). All prescribed drugs in his blood were within the therapeutic range. The Consultant Histopathologist explained that the prescribed drugs had combined in a synergistic effect, acting together to poison Stuart. My concern is that in the prescription of medication, particularly those that act on the central nervous system and affect respiration control, full account should be taken of the totality of drugs prescribed and their potential synergistic effect. The reasons for my concern are: Four prescription drugs namely Diazepam, Pregabalin, Amitriptyline and Promethazine were all found at a level consistent with therapeutic use. Each of these alone was at a level not expected to kill however each can exacerbate the effect of the other. I understood from the evidence that each of the drugs have a direct effect on the central nervous system. In particular a depressive effect on respiration. The Consultant Histopathologist confirmed this to be the case. In addition to those prescribed drugs, methadone was also prescribed at 60 mg daily. That is well within normal prescription range. It was found at a level of 507ng/mL in blood. Methadone also has an effect on the central nervous system and is another respiratory depressor. The toxicology report said: “...the deceased was prescribed 60mg of methadone daily. It has been reported that in 20 long-term opiate addicts who were administered a mean oral dose of 60mg methadone (range 10-225mg), the peak blood methadone concentrations ranged between 124-1255 ng/mL. It has been reported that in a study of 18 patients maintained on methadone 7.5 to 130 mg daily for at least 2 months, peak plasma concentrations of 69-698 ng/mL (pre-dose concentrations: 44-614 ng/mL) were achieved in 3 hours. The blood methadone level in the deceased was 507 ng/mL which may, therefore, reflect therapeutic use”. It is of course, not known how much methadone Stuart had taken or when. However, properly taking the prescribed dose could still achieve the recorded level. To put the amount of methadone into context, the toxicology evidence indicated a therapeutic range of 75 – 1100 ng/ml in blood; a toxic range of 200 – 2000 ng/ml and a fatal range of 400 – 2000 ng/mL. A level of tolerance builds with regular use. Methadone is a potent opioid narcotic analgesic and would also have a synergistic effect together with the other four drugs mentioned above. Therefore, even taking the properly prescribed medication as prescribed could have led to the situation that resulted in the death of Stuart WALLS. That is, drugs properly prescribed and properly taken could achieve a level, acting synergistically, that caused drug toxicity sufficient to cause death. ”