As this site is not predominantly focussed on health care professionals we’d like to explain in layman terms the risks pharmaceuticals can have. Also we don’t claim to be scientifically complete.
With risks we also incorporate the fact that pharmaceuticals cannot perform their designed effect because of the way they are administered/used.
Basically 6 forms of Medicine Risks can be distinguished:
Evidently a medicine has a certain dosage range (for a certain illness or health problem) for which it is designed or should be effective. Both over and under dosage are equally not desirable. The first leading to the fact that the medicine cannot have enough effect, the latter to possible poisoning. Especially with medicines which have a ‘narrow therapeutic window’ (this means there is only a small difference in medicine blood concentrations between desired and poisonous).
Dosage adaptations usually are necessary in the case of small children, the (very) elderly and when there are already existent health problems with kidneys and/or liver (as these last two organs play a big role in the excretion of the medicines out of the body).
Basically in this situation a new medicine interacts with the desired effects of the other, already existing, medicine. Possible are an increase or decrease in the activity of the existing medicine or an increase or decrease of the added medicine.
Usually this interaction comes forth out of the effects on the biochemical metabolism and/or excretion of a medicine. But also a more direct (physic) effect is possible in which the two medicines form a chemical complex which is not active anymore.
Notorious, and widely used in developping countries, medicine groups are: HIV-, Tuberculosis- and Malaria medicines.
In this situation there is an existing health condition (for example diabetes) which makes it not desirable, or even dangerous, that a certain (group of) medicine(s) is used.
Here two, or more, medicines are used which have an (not desired) effect on the same physiological system. Henceforth the toxicity increases.
Here a certain patient has (developed) a condition in which a certain (chemical) compound (or group of compounds) is not tolerated by the individuals body. The effect of it can be that this specific person develops an (serious and life threatening) allergic reaction upon administration of the specific compound.
Pathway and others
This is a more broad area and can be divided in the following sections:
-Administration: a pharmaceutical is designed to be used in a specific way so that it can be effective in delivering the active compound(s) at the right place (for example; tablet, injection, potion, inhalation device, suppositories). Logically the planned effects can be less or even dangerous when not used correctly. Especially inhalation devices (e.g. for Asthma, COPD) are ‘famous’ for not being used correctly. The result being that the medicine does not have enough effect.
-Administration context: the biological availability, and therefore desired effect, of oral medicines can be significantly influenced by the fact if they are taken at an empty or opposite, filled stomach. Another simple example is the necessary shaking, before use, of fluid formulations which also contain solid particles.
-Expiring date: producers label their medicines with an expiry date. Until this date, and kept under the right storage conditions, the quality of the medicine is guaranteed. When medicine pots are used instead of medicines packed in blisters, chances of fraude (re-labelling) become enhanced.
-Storage: depending on the specific medicine strict storage conditions can apply, both in the pharmaceutical chain as when the medicine is in the patients possession. For example protection from heat (e.g. vaccines, insulin’s), cold (e.g. insulin’s) or moisture. Incorrect storage usually diminishes the medicines activity but also chemical changes can lead to new, more dangerous, compounds.
-Falsification: due to fraudulous production practices the medicine intentionally does not contain the claimed substance(s) in the claimed amounts, or even contains completely other substances. Especially in the develloping world this is a serious problem and creates distrust amongst the general public especially towards generic medicines.