Adverse Drug Reactions

We have read recently at the papers the case of adverse reactions to Nolotil in humans. Some deaths have been reported these last years in people who were on this painkiller. The symptoms consist on a dramatic white blood cells drop (agranulocytosis), and the strange thing is a minimum percentage of these cases were reported in Spaniards. The disappearing of granulocytes, whose role in immunity is critical, implies the individual is unable to fight against any kind of infection, so even a small, banal injury may develop a lethal infection.

For this reason, Nolotil has been forbidden in some countries such as Sweden and UK. Meanwhile, in Spain, Nolotil is the most widely used painkiller, and it’s absolutely necessary for millions of people in order to have a normal, free of pain, life. Why does this happen? Because genetic differences between individuals make some of them sensitive against substances which are totally harmless for other people (or animals).

Logically, in every country, natives share most of their genetic material. This explains, for example, Swedish people are normally blonde and taller than Spanish.

These adverse drug reactions (ADR) appear in animals too. First of all, we have to make a difference between allergic reactions and ADR: for example, is not the same thing being allergic to seafood than having “bad digestions” after eating seafood.

In Veterinary Medicine, breeds peculiarities concerning medicines and diseases are being profusely investigated, and they are a very valuable tool for diagnosis and treatment. It’s absolutely necessary to know very well which are diseases are prone to suffer certain breeds, and which medicines mustn’t be used in certain breeds and species. The typical example is the antiparasitic medicine (for both internal and external parasites) Ivermectin, which was a real revolution (and still is) when it appeared at the market. It’s an extremely efficient medicine and practically free of side effects in most animals, but in case of Collies and related breeds (Rough Collie, Border Collie, Bearded Collie, Shetland, etc) can be lethal due to a molecular particularity of haematoencephalic barrier in these animals. Of course, there are some labs which offer DNA tests to make sure if an individual has this abnormality at its genoma, but it makes nonsense to perform this expensive test in every Collie. It’s much more logical just not to use this medicine in these breeds. The real problem appear in crossed animals: a dog may look externally like a German Sheperd, but who knows if one of its grandparents was a Collie and transmitted the wrong gene to its grandchild? For this reason, it’s not easy to predict how it’s going to be the effect of a medicine like in a non-pure breed animal.

ADR are always described at the leaflet, and they are classified according frequency of appearing and severity. This ADR will appear even when giving the right dosage, they have nothing to do with overdose or with a wrong way of administration (for example using in an empty stomach a medicine which has to be given with some food, or vice versa).

If you are suspecting an ADR in our pet, you have to report it to the Vet immediately in order to start a pharmacovigilance proceeding. So, making medicines safer is a task of both sanitaries and people who uses them (in case of pets, the owners).

Liliana Aldeguer Cerdán col 793
English translation by
Sergio Reina Esteban col 747

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