gms | German Medical Science

Aim: Professional and amateur athletes increasingly engage in endurance sports. In order to prevent pain inhibiting their performance, many athletes ingest over-the-counter (OTC) analgesics before competing. We investigated the impact of analgesics on performance and adverse events (AEs) during the Bonn marathon and half marathon races 2010, using an electronic questionnaire which was available online to all participating runners.

Method: Binary logistic regression models were used to calculate the risk of spontaneously reported AEs associated with analgesic use and ingested doses overall, and by various subgroups.

Results: Out of 7,048 participants, 3,913 responded with questionnaires that became the primary study population. Of all respondents, 49% (n=1,931) ingested analgesics before the start of the marathon/half marathon, mostly to prevent pain. Predominantly diclofenac (n=913; 23%) and ibuprofen (n=722; 18%) were used, but other analgesics, including aspirin (n=102; 3%), were also taken.

There was no significant difference between the premature race withdrawal rates in the analgesics cohort and the cohort who did not take analgesics (control group). Race withdrawal due to muscle cramps occurred more often in controls (3% vs 1%, p<0.001). On the other hand, intestinal cramps were more frequently reported in the analgesics cohort to be a reason for withdrawal (2% vs 1%; p<0.01).

The analgesics cohort had a four to ten times higher incidence of each type of AE (gastrointestinal, cardiovascular, and renal AEs; overall incidence 16% vs 4%). The overall risk for analgesic-related AEs was estimated at 5.1 (95% CI 3.9 to 6.7; p<0.001) for unadjusted and 3.0 (95% CI 2.1 to 4.1; p<0.001) for sex, age, exercise (marathon/half marathon) adjusted variables.

Using analgesic dose information, a further adjusted regression model showed a significantly increased risk at rising doses, meaning that increasing the dose (no drug – low dose – high dose) increases the risk of AEs by three times on each step (OR 3.2; 95% CI 2.7 to 4.0; p<0.001).

Conclusion: In conclusion, OTC analgesics taken before endurance sports may cause potentially serious AEs. The incidence of AEs increased with rising dose, but the desired drug effects were not evident.

Note: Study data are published online in [1].