Drug companies spend many millions of dollars on clinical trials getting drugs assessed for safety and effectiveness. But the real test of a drug’s safety and effectiveness is when it comes on to the market.
Drug trials do not allow for the testing of all possibilities in terms of such things as interactions a new formulation might have with other drugs, or that the drug might affect certain groups of people not included in the trials. So even if we can trust drug trials to be run with integrity (and there is a great deal of research challenging that they are run in that manner), we are reliant on post-marketing surveillance, or pharmacovigilance, to determine the safety of drugs.
In New Zealand, we have a passive system of pharmacovigilance. That is, the agency that receives reports, the Centre for Adverse Reactions Monitoring, does so through voluntary reporting. CARM does not actively seek out potential problems.
However, very few people who are not health professionals know about CARM, so if people think they are having a problem resulting from a prescribed drug they are most likely to tell their GP or another health professional. The problem is that, throughout the world, research has shown side effects to medications are dramatically underreported by health professionals.
The case of Eltroxin, a drug used to treat hypothyroidism, shows how pharmacovigilance can be enhanced by going around health professionals.
Back in 2007, a new formulation of Eltroxin was introduced by manufacturer GlaxoSmithKline. At the time PHARMAC subsidised the drug, so 70,000 New Zealanders were phased on to the new formulation. It was thought the new formulation was bioequivalent to the old one – that is, it was thought to absorb, metabolise and excrete from the body in an equivalent way. Yet after the new formulation came on to the market, there was a 400-fold increase in patient-reported adverse drug reactions for Eltroxin, with some severe reactions perplexing the health profession.
Medical authorities and researchers made various attempts to explain this increase. Patients were blamed for being non-compliant (why they were suddenly non-compliant to the new formulation was not explained) or for being irrational in an environment where people were suspicious of PHARMAC and so on. But by looking very closely at how this situation unfolded, new avenues for undertaking pharmacovigilance in New Zealand can be considered.
An extremely important element in the Eltroxin case was the media. Regional newspapers picked up initial concerns from pharmacists and published details of how people could contact CARM. In addition, politicians became involved, publishing details in media releases about how to contact CARM. Concerns raised in regional newspapers (The Southland Times being central in this case) meant people having unexplained symptoms could consider the new drug formulation as a possible cause.
People came together to form support groups and gained further publicity about the potential problem. With new information about how to report adverse reactions and greater awareness about concerns, CARM started receiving a sharp rise in reports. Reports did come from GPs, who were now made more aware of concerns about Eltroxin as a result of the media coverage, but also many reports came directly from patients, something that is very rare in New Zealand.
The role of PHARMAC in pharmacovigilance is important to note. Because PHARMAC initially subsidised just the one drug, patients could not easily switch to other drugs if Eltroxin was not suiting them. In other countries, this is not the case, so the problems with the new formulation of Eltroxin were more likely to be identified here than anywhere else in the world.
The passive reporting system, or voluntary self-reporting, worked well in the case of Eltroxin. Once PHARMAC subsidised other drugs patients could switch to, the problem went away. But this is a rare and unusual case.
To enhance pharmacovigilance in situations where adverse drug reactions are a major cause of death, we need to think outside the box. People given prescription drugs need to know who to report concerns about the drug to, and how to do so. Pharmacovigilance agencies like CARM should be resourced so they can take a more active role in identifying potential post-marketing problems, such as accessing (with permission) the online posts of patient support groups to see if there are any leads.
And as the Eltroxin case shows, regional newspapers and other media are a valuable resource too: to be monitored for reports of concerns about adverse drug reactions and as a way for pharmacovigilance agencies themselves to raise concerns and share information.
Read the original article on Newsroom.