What Types Of Side Effects Are There When Taking Medicines?

Basically, there are predictable and unpredictable side effects. When taking medication, it is always essential to get sufficient information from a health professional beforehand in order to avoid them as much as possible. 

Statistics show that around 7 percent of the population experience side effects  from medicines they take. So it is a public health problem.

A side effect (NW for short), often also referred to as adverse drug reaction (ADR for short), is any response by the body to a drug that is harmful or unintentional and occurs at a normal dose. 

This can be a prophylactic or diagnostic dose, or the amount needed to treat a disease. There are also special dosages for rehabilitation, corrections or changes in biological functions.

The most common drugs that cause side effects include:

• Non-steroidal anti-inflammatory drugs

• Antibiotics

Who provides information about the possible side effects of a drug?

The German Federal Institute for Drugs and Medical Devices provides information about side effects and also receives reports of adverse drug effects from specialists, citizens and patients. A separate form is available for this on the website of this institute.

However, the most important information is usually provided by the doctor who prescribes the drug or the pharmacist. It is important for the patient to get good advice and to ask if there are any doubts.

This is of particular importance when other drugs are also taken and there could be interactions. There may also be diseases for which certain drugs are contraindicated.

In addition, it is also important  to read the package insert carefully, which also contains very important information. All known side effects are listed and the package insert also provides information about possible courses of action in the event of a side effect.

All commercially available drugs can cause undesirable effects. Nevertheless, they are used because they have more health advantages than disadvantages.

Types of side effects

In general, there are two broad groups of adverse drug effects: predictable and unpredictable effects.

Foreseeable effects

80 percent of all adverse drug reactions are predictable. These effects often depend on the dose, i.e. the higher the dose, the more likely or more intense the side effect.

In addition, side effects that are directly related to the pharmacological action of the drug are common, for example:

• Side effect due to the mechanism of action of the drug,
• interaction with other drugs or substances,
• or from overdosing.

Unpredictable side effects

These adverse drug effects are not dependent on the dosage and can therefore also occur with small amounts. They are also not related to the pharmacological action of the drug. 

Unpredictable side effects arise from factors that depend on the patient. Because they occur when a person’s immune system reacts sensitively or, for example, there are genetic differences that increase the risk. 

Within the unpredictable drug effects, we can differentiate between the following:

• Intolerance:  If the patient does not tolerate the active substance even in small doses. For example, some people begin to tremble at the slightest dose of salbutamol.
• Idiosyncrasy:  In this case, the reactions are usually genetic and lead to hypersensitivity to the drug. The patient suffers from an enzymatic or metabolic disorder which can result in serious effects in the processing of the drug. However, these effects are relatively rare. 

• Hypersensitive or allergic reactions:  In this case it is an abnormal reaction of the immune system. For example, there may be an allergy to penicillin.
• Pseudoallergic or anaphylactic reactions:  These cannot be clinically differentiated from the allergic reaction, but the triggering mechanism is different because the immune system does not play a role. This can happen, for example, when taking opioids or other drugs.

Other types of adverse drug reactions

In addition to the adverse drug reactions already mentioned, there are other types that can result from pharmacological treatment. These include, for example, type C side effects.

These drug effects are dose and time dependent. They are usually predictable if the medicine is used over a long period of time. This group includes drugs that produce addiction, such as benzodiazepines. Possible consequences are also tardive dyskinesia (movement disorders) caused by neuroleptic drugs or Cushing’s syndrome caused by corticoids.

Type D side effects are very rare. They are delayed after treatment has ended. For example, teratogenic effects can occur, which means that they can cause malformations in fetuses. Carcinogenesis can also result, which means that a tumor can form.

Type E adverse drug reactions, are all those that occur after suddenly stopping the drug. Examples of this are: renal insufficiency after stopping corticosteroids, an epileptic seizure after stopping an anti-epileptic drug, or angina after stopping beta-blockers.

Final résumé

It is essential to be informed about adverse drug effects, because  all commercially available drugs can trigger them. Side effects can be dangerous in some cases,  so get your doctor or pharmacist well informed and read the package insert before you start taking it!