Tolerance, tolerability, innocuousness, safety, relationships and differences

By Nicolas Gambardella

When it comes to clinical trials and pharmacovigilance, using the right word is crucial for an accurate and precise shared understanding. Unfortunately, this is not always the case, even in documents written by specialists. While this can sometimes lead to a certain degree of vagueness in communication within a given language, the situation becomes worse when it comes to documents that need a translation. Especially as the use of given terms may be subject to hyponyms/hyperonyms relationships that differ according to language and context.

In this post, we will look at some terms that generate endless debate in professional forums, all related to safety efficacy data associated with treatments, namely: tolerability, tolerance, safety, innocuousness, and their French equivalents, tolerability, tolerance, safety and innocuousness.

Tolerance and tolerability

Tolerance to treatment is the word used in pharmacology and clinical trials to designate habituation, i.e. the fact that the same intensity of treatment leads to increasingly weaker effects (note that in the field of drug of abuse, the terms tolerance and addiction carry sometimes a subtle difference: Tolerance is the fact that a given dose leads to an increasingly weaker effect, whereas addiction means that higher and higher doses are needed to obtain a given effect). The French translation of tolerance is tolérance.

Tolerability characterises the subject’s ability to withstand adverse effects. While tolerance refers to efficacy data, tolerability refers to safety data. It is a precise term from clinical trials and is not found in any standard dictionary. The French translation of tolerability is tolérabilité. Let’s be honest, these terms are atrocious. However, when it comes to patient safety, the literary elegance and aesthetics of the word are less important than precision and accuracy. “Tolérabilité” is often criticized as “anglicism”, with critics encouraging the use of tolerance to translate tolerability (following in that many French dictionaries). This is forgetting that, in addition to being false, tolerability is itself originally an Anglicism. Perhaps one way to clarify things is to look at adjectives. A person is tolerant to a drug, while a drug is tolerable for a person.

Safety and innocuousness

We are now entering a turbulent zone where tempers flare and linguists grapple with each other. Most of the time, because they are not versed in the handling of ontologies and hyponym/hyperonym relationships. Do safety and innocuousness refer to different concepts? Yes. Do the concepts of safety and innocuousness overlap? Yes. Do safety and innocuousness always translate into the same French terms? No.

Let’s start with innocuousness. The innocuousness of a drug is its ability to work without causing adverse effects (harmlessness). A drug that is innocuous is a safe drug. The term is rarely used in practice, see below. The French translation of innocuousness is innocuité. It should be noted that innocuousness and tolerability are not synonyms. A drug may have a bad innocuousness but good tolerability. For example, it could cause side effects in most cases, these effects being well tolerated.

Where things get complicated is when we approach the notion of safety. The French translation of safety is sécurité. Depending on the context, the concept of safety covers a more or less broad semantic landscape. We will translate the expression “safety and tolerability” by “innocuité et tolérabilbilité“. However, in the expression “safety and efficacy”, safety covers both innocuousness and tolerability. Therefore, we will translate the expression into “sécuritéet efficacité“. Note that “safety” is never translated into “sureté”, although “safe” is translated into “sûr”.

Finally, let us agree that while the greatest precision is necessary between health professionals, it must not lead to pedantry that hinders clear and elegant communication with the patient. We will therefore translate our “commitment to ensuring your safety” into our “engagement à garantir votre bien-être” and not “garantir votre sécurité “. Unless the practitioner is also a bodyguard.

Leave a Reply