198 deaths linked to drug reactions

  • Niall Hunter, Editor

A total of 198 deaths were recorded by the State drugs monitoring agency last year among adverse reactions linked to particular medicines.

Figures obtained by irishhealth.com from the Irish Medicines Board show that of the 2,757 adverse drug reaction reports it received during 2012, 198 patients were reported to have died while on treatment with these drugs.

The highest number of reported deaths were associated with drugs used to treat serious kidney disease and schizophrenia, the figures show, with some deaths also reported linked to cancer and heart drugs.

The IMB has stressed that the reported deaths linked to medicines do not necessarily indicate a direct link between taking a particular drug and the subsequent death of the patient, many of whom would have already been seriously ill.

The figures also show that there were 328 adverse drug reactions linked to the childhood immunisations and the HPV (cervical cancer) vaccine last year. However, no deaths were reported as linked to these vaccines.

The medicines board told irishhealth.com that in many cases where patients were reported to have died while on treatment, they would have had significant underlying illnesses and were treated with multiple medicines and/or surgery, which may also have contributed to fatalities.

It said in addition, many of the fatal cases would have been affected by disease progression and other complications unrelated to the medicine linked to the death in the report.

The highest number of deaths recorded among the ADR reports last year - 28 - were in patients being treated with epoetin beta, used in the treatment of chronic kidney disease.

The second highest mortality number -20- was in patients on the drug methoxy polyethylene glucol-epoetin beta, also used in serious kidney disease.

The third highest number of reported fatalities -18- was in patients treated with clozapine, used in patients with psychosis/schizophrenia.

Other reported fatalities in 2012 include seven in patients taking methotrexate, which is used in the treatment of arthritis and cancer, seven with adalimumab, often used in rheumatoid arthritis; five with cyclophosphamide, used in cancer treatment, and five linked to a cardiovascular drug, dabigatran, used in stroke prevention.

There were four deaths reported in patients taking ipilimumab, used to treat malignant melanoma.

The IMB says where it stresses the need for close monitoring of patients, this generally leads to increased reporting of adverse reactions, which can include reporting of events not directly related to a drug, but occurring during the time a patient was treated.

It says deaths reported in patients on a particular drug can be due to deterioration in their condition and may not be directly attributable to the medicine.

Of the the 2,757 drug ADRs reported last year, the highest number - 244 - was linked to the schizophrenia medicine clozapine, which is the only psychiatric drug in the top 10 most commonly reported medicines linked to adverse reactions and in the top 10 most commonly reported drugs linked to fatalities.

Clozapine, which can cause serious side-effects, was previously withdrawn from the market and then reintroduced in the 1990s under strict monitoring guidelines.

The second highest number of adverse reactions - 185 - was associated with vaccines used in the childhood immunisation scheme, while the third highest - 143- was linked to the HPV (cervical cancer) vaccine.

The IMB, commenting on the type of adverse medicine reactions reported, said the number of reactions reported 'cannot be taken as an indicator of safety or risk'.

"The number of reports received cannot be used as a basis for determining the incidence of a reaction, as neither the total number of reactions occurring, not the total number of patients using a medicine is known. Adverse reaction reporting rates are influenced by the seriousness of the reactions, their ease of recognition and the extent of use of a particular medicine."

The drug monitoring body says that it can be difficult to establish whether a particular vaccine has directly caused an adverse reaction, as many vaccines are administered in combination with others.

The IMB told irishhealth.com that  drug reaction reporting rates in general can also influenced by healthcare professionals being urged to submit reports on certain drugs as part of post-marketing surveillance. It added that publicity about a particular medicine or its safety can also lead to increased reporting.

The majority of adverse reaction reports (69%) to the IMB come from drug manufacturers, with 18% coming from doctors, 8% from pharmacists, 2% from nurses and 2% from patients/consumers.

The IMB does not publish details of the drugs linked to adverse reactions, or the number of deaths associated with adverse reactions in its annual report.



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