Figure 1. Number of ME notifications and incidence rates per quarter (Catalonia, 2019–2021). Significant differences in incidence: * vs. second quarter of 2019, † vs. fourth quarter of 2019 (p < 0.05).

Figure 2. Percentages of reported MEs based on the places where the MEs occurred (Catalonia, 2019–2021).

Table 1. Numbers and percentages of ME cases based on the causes and processes of the therapeutic chain involved in the ME (Catalonia, 2019–2021).

Table 1. Numbers and percentages of ME cases based on the causes and processes of the therapeutic chain involved in the ME (Catalonia, 2019–2021).

Cause of MECases 2019Cases 2020Cases 2021Global Cases(n = 632)%(n = 748)%(n = 579)%(n = 1959)%Incorrect, incomplete, illegible, or verbal medical prescription23937.833745.123440.481041.3Incorrect prescribed dosage9715.38110.86511.224312.4Therapeutic duplication409.8586.8595.21578.0Incorrect administration467.3557.4478.11487.6Lack of information626.3517.83010.21437.3Patient non-compliance194.9343.3273.3804.1Similarity of packaging313.5252.5193.3753.8Incorrect dispensing223.2193.1192.8603.1Other causes203.2232.1163.6593.0Similar names203.0164.5214.7572.9System error (structure, process, or organization)122.8281.3153.8552.8Incorrect prescription verification181.9103.7222.6502.6Incorrect preparation50.881.140.7170.9Incorrect or misleading labelling10.230.410.250.3

Table 2. Numbers and percentages of ME notifications based on severity category (Catalonia, 2019–2021).

Table 2. Numbers and percentages of ME notifications based on severity category (Catalonia, 2019–2021).

ME Severity CategoryNotifications 2019Notifications 2020Notifications 2021Global Notifications(n = 442)%(n = 536)%(n = 416)%(n = 1394)%A: Circumstance capable of causing an ME317.0213.9143.4664.7B: The ME occurred but was detected before reaching the patient29566.737970.726363.293767.2C: The ME did not cause injury to the patient8018.110319.28821.227119.4D: The patient required observation, but no injury occurred102.391.7174.1362.6E: The patient required treatment and/or the ME caused temporary injury235.2234.3297.0755.4F: The patient required hospitalization or hospitalization has been prolonged and has caused temporary injury30.710.251.290.6G: The ME caused a permanent injury to the patient00.000.000.000.0H: The ME caused a situation that came close to causing the death of the patient00.000.000.000.0I: The ME caused or contributed to the patient’s death00.000.000.000.0

Table 3. Numbers and percentages of drugs involved in the MEs reported according to the organ or system on which the drug acted, based on ATC code descriptions (Catalonia, 2019–2021).

Table 3. Numbers and percentages of drugs involved in the MEs reported according to the organ or system on which the drug acted, based on ATC code descriptions (Catalonia, 2019–2021).

ATC CodeATC Code DescriptionGlobal Notifications(n = 1505)%NNervous system28719.1CCardiovascular system23915.9AAlimentary tract and metabolism23015.3JAnti-infectives for systemic use17811.8RRespiratory system1338.8BBlood and blood-forming organs895.9MMusculoskeletal system855.6HSystemic hormonal preparations, excluding sex hormones and insulins724.8SSensory organs553.7DDermatological543.6GGenitourinary system and sex hormones442.9OthersMedical devices and food supplements140.9LAntineoplastic and immunomodulating agents130.9PAntiparasitic products, insecticides, and repellents90.6VVarious30.2

Table 4. Numbers and percentages of the drugs most frequently involved in the MEs reported, according to the classifications by therapeutic group based on the ATC code descriptions (Catalonia, 2019–2021).

Table 4. Numbers and percentages of the drugs most frequently involved in the MEs reported, according to the classifications by therapeutic group based on the ATC code descriptions (Catalonia, 2019–2021).

ATC CodeATC Code DescriptionGlobal Notifications% Global NotificationsJ01CBeta-lactam antibiotics and Penicillins755.0B01AAntithrombotic agents694.6M01AAnti-inflammatory and antirheumatic products and non-steroids583.9N06AAntidepressants583.9A11CVitamins A and D, including combinations of the two563.7N02BOther analgesics and antipyretics553.7A02BDrugs for peptic ulcer and gastro-esophageal reflux disease453.0N02AOpioids453.0A10BBlood glucose-lowering drugs, excluding insulins442.9H02ACorticosteroids for systemic use, plain442.9C10ALipid-modifying agents, plain382.5N05BAnxiolytics352.3R03BOther drugs for obstructive airway diseases and inhalants342.3A10AInsulins and analogues322.1N05AAntipsychotics312.1J01FMacrolides, lincosamides, and streptogramins291.9C09ASelective calcium channel blockers with direct cardiac effects281.9R06AAntihistamines for systemic use271.8N03AAntiepileptics261.7R03AAdrenergics and inhalants251.7C03CHigh-ceiling diuretics251.7J01XOther antibiotics251.7A12AMineral supplements241.6C09DAngiotensin II receptor blockers (ARBs) and combinations thereof231.5C07ABeta-blocking agents221.5S01EAntiglaucoma preparations and miotics201.3C08CAce inhibitors and combinations thereof201.3H03AThyroid preparations201.3

Table 5. Characteristics of the serious ME cases reported (Catalonia, 2019–2021).

Table 5. Characteristics of the serious ME cases reported (Catalonia, 2019–2021).

DrugSource of MECause of MEAdditional Pharmaceutical ActionADR AssociatedRocoz® 100 mg (API * Quetiapine)Pharmacy officeIncorrect dispensingThe two pillboxes causing the error were separated due to similarity in the names of the patients.UndefinedClopidogrel Normon 75 mg EFG †Patient’s homeLack of information and patient non-complianceThe pharmacist urged the family to review the medication with the prescribing physician.Stroke due to patient non-complianceAugmentine® 500 mg (API * Amoxicillin/clavulanic acid)Primary care centerIncorrect medical prescriptionNoneThe patient attended the primary care center with chest pain angina and was prescribed Augmentine® 500 mg. Two days later, he returned to the emergency room because he had chest pain. The patient was referred to the hospital, where pericarditis was detected due to an incorrect prescription of the antibiotic dose.Fentanyl® Stada 75 µg EFG †Patient’s homeIncorrect administrationThe patient applied the new patch without removing the old one because he thought the drug had worn off. The pharmacist explained to the patient when and how to remove the fentanyl patch.Drowsiness, hypotension, and light headedness that resulted in requiring treatment in the primary care center.Furosemide Cinfa 40 mg EFG †Primary care centerIncorrect medical prescription and system error (structure, process, or organization)NoneThe patient had edema in the leg because the doctor forgot to renew the furosemide in the electronic prescription and the patient stopped taking the medication. The patient was hospitalized for ten days.Eliquis® 2.5 mg (API * Apixaban)HospitalIncorrect medical prescriptionNoneThe patient was taking acenocoumarol to prevent thromboembolism secondary to a mechanical heart valve. After the change in medication from acenocoumarol to apixaban, the patient suffered another myocardial infarction, with hospitalization and subsequent surgical intervention.Sintrom® 4 mg (API * Acenocoumarol)Primary care centerIncorrect prescribed dosage and system error (structure, process, or organization)NoneElevated international normalized ratio (INR)Amoxicillin/clavulanic acid Mylan 500 mg EFG †Patient’s homeOther causesDue to the ADR experienced by the patient, the pharmacist advised referring him to the doctor so that he could take it into account in future prescriptions.After the administration of six doses of antibiotic, the patient stopped the treatment due to the appearance of hemorrhoids. The patient attended the hospital, where she was prescribed a cream for the hemorrhoids.Prednisone Alonga 50 mg EFG †Primary care centerIncorrect medical prescription and lack of informationThe patient was diabetic and suffered facial paralysis. Prednisone 50 mg was prescribed and her basal glycemia rose to 600 mg/dL. The patient was admitted to the hospital and was under observation, where she was administered rapid insulin. The pharmacist advised her to periodically check her glucose levels and take note of when the medication was stopped.Hyperglycemia