Pertinent Insights On Drug-Induced Arthralgia With Commonly Prescribed Drugs

Robert G. Smith, DPM, MSc, RPh, CPed

Understanding Pharmacovigilance And Medical Causation

It was not until the disaster caused by thalidomide in 1961 that the first systematic international effort began to address drug safety. The principal goal of pharmacovigilance is the detection of adverse events related to the use of drugs that are unknown or novel in terms of clinical pattern, severity or frequency.2 The World Health Organization defines pharmacovigilance as the science and activities relating to the detection, assessment, understanding and prevention of adverse effects or other drug-related problems.6

   Pharmacovigilance continues to play a crucial role in meeting the challenges posed by the ever increasing range and potency of medicines, all of which carry an inevitable and sometimes unpredictable potential for harm.

   The definition of an adverse effect is an untoward physical sign or symptom, an abnormal assessment, or cluster of signs or symptoms. The impact of adverse drug effects results in significant cost and inflicts unnecessary harm (sometimes fatal harm) to patients.7 Adverse effects would function as a distraction because the presence of an adverse effect could mimic actual biological pathology and thus distract the clinician from identifying the actual cause of the patient’s presenting symptoms. (For example, if a medication adverse effect was nausea and vomiting and physicians did not identify the nausea and vomiting as a adverse effect, they may perform an radiological test and blood work on the patient, thus being distracted from the actual cause of the nausea and vomiting. This can result in unnecessary investigations and a delay in treatment.6,8

   The difficulty with the diagnosis of adverse drug reactions is that these reactions represent exceedingly complex clinical phenomena.9 This complexity may be related to: discrepancies in the incidence of adverse drug reactions reported in epidemiological studies; the non-specificity and suggestibility of symptoms attributed to adverse drug reactions; and inter-observer disagreement among experts in the diagnosis of adverse drug reactions.9

   The definition of medical causation is an adverse effect that occurs as a result of treatment with medication, biological, vaccine, device or procedure.10 We can describe causation in “degrees of relatedness” as unrelated or definitely, probably or possibly related to a treatment.10,11 Hill’s criteria for causation outlines a systemic approach for using scientific judgment to infer causation from statistical associations observed in epidemiologic data.12

What You Should Know About The Effects Of Common Medications

I conducted a search of various electronic sources for data regarding drug-induced arthralgia as a medication adverse effect during the time period of 1953 to 2011. The medications I selected for review were the 200 most frequently prescribed (brand and generic names) in 2010 as measured by the IMS Institute for Healthcare Informatics.13 The data were primarily qualitative and were based on reports in the current compendium of recent journal articles and package inserts.2-4,14,15

   The prevalence rates of arthralgia as an adverse drug effect were not available for all 200 medications reviewed. Current literature sources resolved conflicting information presented in reference materials. The recommendations presented in the table, “A Guide To Medications, Arthralgia Prevalence Rates And Mechanism Descriptions,” center on the applied sciences of pharmacology and physiology, as well as clinical intuitive judgment that balances patient benefit with patient risk.

   As part of my search of databases and literature, I derived counts and rates arithmetically to determine the frequency of possible mechanisms or explanations for medication-induced arthralgia using the nine main groups Hart previously described.4

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