I have finally received the Bravecto and Nexgard Adverse Drug Event (ADE) reports from FDA! I made a Freedom of Information Act request for these reports on June 17, 2015, after hearing from so many of you whose dogs experienced side effects after taking these drugs. I wanted to see what adverse events had been reported to the manufacturers and FDA, since our experience with these drugs is quite limited.
Both reports contain information for the time period 1/1/2013 – 06/17/2015. For this time period, there were a total of 5,087 ADE reports received for afoxolaner (Nexgard) for dogs, and a total of 2,467 ADE reports received for fluralaner (Bravecto) for dogs.
Before you delve into the reports, here is some important information. This is all included in the first two pages of the reports, but I want to highlight it here:
- The Center for Veterinary Medicine (CVM) states “The primary purpose for maintaining the CVM ADE database is to provide an early warning or signaling system to CVM for adverse effects not detected during pre-market testing of FDA approved animal drugs and for monitoring the performance of drugs not approved for use in animals. CVM’s ADE reporting system depends on detection and voluntary reporting of adverse clinical events by veterinarians and animal owners.”
- “Clinical signs reported for an active ingredient are listed in order from most frequently reported to least frequently reported, grouped by species and route of administration.”
- “More than one clinical sign may have been reported per ADE case report, so the ‘Number of times reported’ column is not additive and does not necessarily represent the total number of reports received.”
- “For any given ADE report, there is no certainty that the reported drug caused the adverse event. The adverse event may have been related to an underlying disease, using other drugs at the same time, or other non-drug related causes. The clinical detail listing does not include information about underlying diseases, other drugs used at the same time, other non-drug related causes, or the final outcome of the reaction.”
- “The accuracy of information regarding the ADE is dependent on the quality of information received from the reporting veterinarian or animal owner.”
- “Accumulated ADE reports should not be used to calculate incidence rates or estimates of drug risk, because there is no accurate way to determine how many animals were given the drug, which is needed as the denominator in calculations of incidence and relative risk.”
- “It is inappropriate to make use of adverse event data to compare the safety of different products. For example, if a drug is widely used to treat certain conditions, there may be more ADEs for that drug than another product that is not used as often. This would not mean that the first drug was more unsafe than the second.”
- “Underreporting occurs with most adverse event reporting systems. The frequency of reporting for a given drug product varies over time, and may be greater when the drug is newly marketed, or when media publicity occurs.”
I plan to sift through both reports and group the adverse events by organ system. I’ll write another post when I’ve completed this task. I continue to hear from dog owners whose dogs 1) have had no apparent side effects, and 2) have had side effects ranging from mild and self-limiting to severe, debilitating, and even deadly. My message to everyone is to report anything amiss, even if it seems small. As mentioned above, the CVM uses the database to monitor drugs after they’ve been approved. This is the only official channel to impact whether a drug stays on the market or not. If your dog is having issues and you need help with reporting and support from other folks who’ve been down the same road, head over to Facebook to the Nexgard and Bravecto groups.
I wish you all a Happy Thanksgiving!