What are Adverse Drug Effects?

Though the terms adverse drug effects and adverse drug reactions are interchangeable, there’s a minor difference that needs consideration. Adverse reactions arise against a particular drug or a metabolite within the body tissues that deviates the normal physiological purpose to a pathological one.
Ultimately, adverse effects are clinically diagnosed by the signs and symptoms that appear, while adverse reactions are better understood with lab tests and clinical investigations.
Summing all this up, an adverse drug effect can be defined as an unpleasant reaction that arises as a result of medicinal use that warrants hazards in case of any future administration. Such can be sorted out either by tapering the dose of the regimen or withdrawal of the drug.

Types of Adverse Drug Effects Explained

There are around six types of adverse drug effects that basically define the reason behind the unwanted results arising from a drug type.
  1. Dose-Related (Augmented):
    It shows an augmentation with the pharmacological action of the drug that directly depends on the dose administered.  Warfarin is a blood thinner. It can cause excessive bleeding when the dose isn’t monitored well.
  2. Non-Dose-Related (Bizarre):
    Such reactions are also called idiosyncratic reactions that are just abnormal reactions to food and drugs. Certain antibiotics like penicillin can cause allergic reactions.
  3. Dose-Related and Time-Related (Chronic):
    It happens due to the long-term use of the drug. Chronic use of analgesics like acetaminophen can cause cirrhosis of the liver.
  4. Time-Related (Delayed):
    As the name says, drug effects happen lately after the use of the drug. Mainly lInked with teratogenicity and carcinogenicity. Pregnant females using phenytoin have babies with fetal hydantoin syndrome.
  5. Withdrawal (End of use):
    Such effects arise when a drug is withdrawn abruptly. Like beta-blockers can cause hypotension on withdrawal.
  6. Failure of Therapy (Failure):
    If a particular drug is not offering the required pharmacological benefit, it may end up with an adverse drug effect. Some anxiolytics present a good picture of such adverse drug effects

Clinical Presentation

There can be a lot of clinical presentations that can anyhow coincide with the presentations of several diseases. To suspect reasonably and to rule out the medicinal cause, a clinician is required to take a thorough history.
Here you go with a list of signs and symptoms that occur as a result of an adverse effect to a drug:
  • functional deterioration
  • changes in mental status
  • failure to thrive
  • loss of appetite
  • confusion
  • depression.
  • Itching
  • rash
  • upper or lower airway edema with difficulty in breathing 
  • hypotension
  • malignant hypothermia 
  • anaphylaxis
  • and more


Once the physician has discovered the nuisance behind the symptoms, the foremost steps are considered according to the patients’ type. Either the physician may modify the dose of the drug or discontinue it.
This is later followed by switching a medicinal drug to another type while asking the patient to be on follow-up. Rarely do practitioners focus on eliminating the drug causing adverse effects out of the body to manage an emergency situation.

Final Verdict

Adverse drug effects have always been a challenge to the health care industry, often giving rise to morbidity and mortality if not handled with care. Prevention, therefore, becomes a necessity and requires a therapeutic plan to be executed for susceptible patients.