Table 2.
Descriptions of the 28 opioid-related adverse drug events divided into preventable and non-preventable
| Case | Description* | Preventability score (1–6)† and type of error‡ |
| Preventable opioid-related ADEs | ||
| Cause: dosing errors | ||
| 1 | A man, 90–99 years, admitted with pain after a fall. Oxycodone for the pain was unintentionally prescribed twice instead of once and also administered twice (dose unknown). This resulted in drowsiness. | 6 (prescribing error) |
| 2 | A man, 60–69 years, suffering from colon cancer and liver metastases, was admitted for optimising his analgesics medication. On returning from his weekend leave, he was diagnosed with oxycodone intoxication. During hospital stay, he received a too high dose of the opioid antagonist naloxone (1 mg instead of the ordered 0.4 mg), which caused confusion and agitation. | 6 (administration error) |
| 3 | A woman, 70–79 years, admitted with a pelvic fracture after a fall. A too high dose (dose unknown) of oxycodone was prescribed and administered resulting in hypotension and drowsiness. Consequently, she needed to be transferred to the intensive care unit. | 5 (prescribing error) |
| 4 | A woman, 80–89 years, admitted with malaise after a fall. During her admission she received a too high dose of morphine. In her patient record, the morphine was ordered as ‘as needed’ (PRN). In the medication list, the morphine was ordered ‘6 times a day’ (dose unknown). This resulted in drowsiness. | 5 (prescribing error) |
| 5 | A woman, 70–79 years, admitted for a plastic surgery. A high dose of intravenous administered anaesthetic/pain medication (dose and medication type unknown) caused hypoventilation and a myocardial infarct. The myocardial infarct was discovered too late. She was resuscitated and ventilated. Her death was possibly caused by a hospital-acquired pneumonia. | 5 (administration error) |
| 6 | A woman, 50–59 years, admitted due to an aspiration pneumonia, was administered morphine. The pump mode was set at 13 mL/hour instead of 8 mL/hour as ordered. This possibly resulted in an epileptic insult requiring ventilation. | 5 (administration error) |
| 7 | A man, 60–69 years, readmitted to the hospital due to a collapse at home. He was previously hospitalised for treatment of rib fractures and COPD Gold IV. At discharge, the doses of fentanyl and oxycodone had been significantly increased to 20 mg 4–6 times a day. Monitoring the effects of increasing these opioid doses was not conducted. | 4 (prescribing error) |
| 8 | A woman, 80–89 years, admitted with osteoporosis, received at home 5 mg morphine two times per day for her back pain. The dosage was increased to subcutaneous 5 mg four times a day during hospital stay. Three days later, a paralytic ileus was discovered. A lower morphine dose was more appropriate for this elderly woman. | 4 (prescribing error) |
| 9 | A woman, 80–89 years, admitted with abdominal pain due to kidney bleeding. She received morphine injections daily, varying from 2 to 6 subcutaneous injections of 2.5 mg per day along with transdermal fentanyl 12 μg hourly. Severe hypercapnia eventually caused her death. | 4 (prescribing error) |
| 10 | A boy, 0–9 years, with Down syndrome, was acutely ill due to a laryngitis. He was difficult to ventilate and received antibiotics and sedatives including opioids. He was transferred to another hospital following detubation. Here, his methadone intake was reduced resulting in a delirium (dose unknown). Initially he improved, but one day unexpectedly he was found dead. It is unclear why this patient received methadone, but reducing the methadone intake may have been the problem. | 4 (unknown) |
| Cause: incorrect decision making | ||
| 11 | A woman, 60–69 years, admitted for a laminectomy. Postoperatively she developed an ileus caused by severe constipation aggravated by administered morphine. Macrogol oral suspension (dose unknown) instead of an enema was given as treatment, which was insufficient to resolve, and the ileus and colon perforation occurred. Untreatable abdominal septic complications followed. | 4 (unknown) |
| Non-preventable opioid-related ADEs | ||
| 12 | A woman, 80–89 years, admitted due to total knee replacement. Postoperatively, drowsiness, hypotension and oliguria occurred, possibly caused by the epidural medication sufentanil (dose unknown). This may have led to a small asymptomatic myocardial infarct. | 3 (administration error) |
| 13 | A man, 80–89 years, admitted with a perforated stomach ulcer and known stomach cancer. His extreme, not previously known, sensitivity to morphine postoperatively (dose unknown) resulted in recurrent apnoea. | 3 (other error) |
| 14 | A woman, 60–69 years, suffering from lung cancer, was admitted with severe back and limb pain related to bone metastases. She was treated with transdermal fentanyl 300 μg/hour. This resulted in drowsiness and hypoventilation. | 2 (prescribing error) |
| 15 | A woman, 80–89 years, known with breast cancer and multiple lung metastases. She received tramadol (dose unknown) for the pain, which have been stopped due to drowsiness. | 2 (unknown) |
| 16 | A man, 70–79 years, admitted with severe heart failure. He received morphine 2.5 mg for the pain. As a result of increased, not previously known, sensitivity to morphine, his saturation dropped. | 2 (other error) |
| 17 | A man, 90–99 years, admitted due to stroke and a lot of pain. The nurse administered 10% of the prescribed dose (dose unknown) of morphine on two occasions, which caused unnecessary suffering. | 2 (administration error) |
| 18 | A man, 60–69 years, admitted for surgery due to an ileus. Postoperative complications included an exacerbation of COPD and hospital-acquired pneumonia after receiving morphine (dose unknown). | 2 (unknown) |
| 19 | A woman, 60–69 years, admitted with a reoccurrence of drowsiness, hypoventilation and difficulties with waking up, which was the result of a dose of 5 mg of methadone being administered in the hospital. | 2 (prescribing and administration error) |
| 20 | A woman, 60–69 years, had a blood pressure drop following the administration of morphine (dose unknown) in the recovery room. | 1 (other error) |
| 21 | A woman, 70–79 years, admitted with pain related to severe Kahler disease. For the pain, she received opioids (unknown which type and dose). The opioids caused drowsiness, and because of the drowsiness she choked once. This caused pneumonia. The patient died during hospitalisation. | 1 (other error) |
| 22 | A man, 70–79 years, received transdermal fentanyl and oxycodone 5 mg daily up to six times due to metastases in the hip. This caused apraxia and confusion. | 1 (unknown) |
| 23 | A woman, 80–89 years, admitted for occlusion of an artery in her leg. She received a morphine infusion (0.5–1.0 mg/hour) causing hypoventilation with a good response to naloxone. | 1 (administration error) |
| 24 | A man, 80–89 years, admitted due to obstructive laryngeal cancer, was prescribed anticoagulants. This resulted in haematoma, along with severe abdominal pain for which he received morphine (dose unknown), after which he died. | 1 (other error) |
| 25 | A man, 60–69 years, admitted with an acute respiratory insufficiency due to pneumonia. He received methadone 20 mg two times per day, causing hypoventilation on two occasions. This needed to be treated with naloxone. | 1 (prescribing error) |
| 26 | A woman, 80–89 years, suffered from pain due to rib fractures caused by resuscitation. She received sufentanil (dose unknown), which led to bronchospasm. | 1 (unknown) |
| 27 | A woman, 70–79 years, admitted with pain related to breast cancer. During the admission, it became apparent that she had metastases along with femur and vertebral fractures. A high dose of morphine (dose unknown) was necessary to relieve her pain, which consequently resulted in a delirium. | 1 (prescribing error) |
| 28 | A woman, 80–89 years, admitted due to a hip fracture and pain. For her restlessness and pain she was administered 1 mg morphine, which probably caused a reduced level of consciousness. | 1 (other error) |
*Patients were categorised in age groups of 10 years to avoid traceability.
†Preventability was scored on a 6-point Likert scale: 1=(almost) no evidence of preventability; 2=small indications for preventability; 3=preventability not very likely, less than 50% but ‘close call’; 4=preventability more than likely, more than 50% but ‘close call’; 5=strong indications for preventability; 6=(almost) certain indications of preventability.
‡For the judgement on preventability and type of error, the experts had access to all information on the electronic patient record and therefore to the whole context in which ADEs occurred. The types of error were prescribing error, administration error, other error (eg, side effects) or unknown.
ADEs, adverse drug events; COPD, chronic obstructive pulmonary disease.