Danish post-marketing pharmacosurveillance of spontaneous Oral Adverse Drug Reactions 2009-2019

Post-marketing pharmacosurveillance is important to reduce harm to patients from marketed drugs. Oral adverse drug reactions (OADRs) are seldom reported and only few OADRs are listed scarcely in summary of product characteristics (SmPC) of drugs.

Structured search for OADRs in the Danish Medicines Agencies database from January 2009 to July 2019.

Forty-eight percent of OADRs were categorized as "serious" where oro-facial swelling was reported 1041 times, medication-related osteonecrosis of the jaw (MRONJ) 607 times and para- or hypoaesthesia 329 times. Four-hundred-eighty OADRs in 343 cases were related to biologic or biosimilar drugs where 73% affected the jawbone as MRONJ. Physician reported 44%, dentists 19% and citizens 10% of OADRs.

Health care professionals had a sporadic reporting pattern that seemed to be influenced by the debate in the community and in professional circles but also by the information in the SmPC of the drugs. The results indicate some reporting stimulation of OADRs in relation to Gardasil 4, Septanest, Eltroxin and MRONJ. Eventually the knowledge of OADRs increases but there is a risk of skewed information if reporting is not systematic, reliable and consistent. All healthcare professionals must be educated in spotting and reporting all suspected adverse drug reactions.