Adverse Drug Reactions

Adverse Drug Reactions

Have you ever had a bad reaction from using any drug?

What did you about this? Did you shake it off and then avoid using the drug? Did you try to find out what caused such reaction or even alert others about the drug.  Such reactions are called Adverse Drug Reactions.

Adverse drug reaction (ADR, or adverse drug effect) is a broad term referring to unwanted, uncomfortable, or dangerous effects that a drug may have. Incidence and severity of ADRs vary by patient characteristics (eg, age, sex, ethnicity, coexisting disorders, genetic or geographic factors) and by drug factors (eg, type of drug, administration route, treatment duration, dosage, bioavailability). Incidence is probably higher and ADRs are more severe among the elderly  although age per se may not be the primary cause. Most ADRs are dose-related; others are allergic or idiosyncratic. Dose-related ADRs are usually predictable; ADRs unrelated to dose are usually unpredictable.

ADRs are usually classified as mild, moderate, severe, or lethal Severe or lethal ADRs may be specifically mentioned in black box warnings in the physician prescribing information provided by the manufacturer. Symptoms and signs may manifest soon after the first dose or only after chronic use. They may obviously result from drug use or be too subtle to identify as drug-related. In the elderly, subtle ADRs can cause functional deterioration, changes in mental status, failure to thrive, loss of appetite, confusion, and depression.

Allergic ADRs typically occur soon after a drug is taken but generally do not occur after the first dose; typically, they occur when the drug is given after an initial exposure. Symptoms include itching, rash, fixed-drug eruption, upper or lower airway edema with difficulty breathing, and hypotension.

ADRs can occur without any known reason and produce almost any symptom or sign and usually cannot be predicted.

Classification of Adverse Drug Reactions

Severity Description Example





















No antidote or treatment is required; hospitalization is not prolonged.





A change in treatment (eg, modified dosage, addition of a drug), but not necessarily discontinuation of the drug, is required; hospitalization may be prolonged, or specific treatment may be required




An ADR is potentially life threatening and requires discontinuation of the drug and specific treatment of the ADR.



An ADR directly or indirectly contributes to a patient’s death


Antihistamines (some): Drowsiness

Opioids: Constipation





Hormonal contraceptives: Venous thrombosis

NSAIDs: Hypertension and edema





ACE inhibitors: Angioedema

Phenothiazines: Abnormal heart rhythm



Acetaminophen overdosage: Liver failure

Anticoagulants: Hemorrhage



Did you know you could report Adverse Drug Reactions in Nigeria?

How? Through PRASCOR; The Pharmacovigilance Rapid Alert System for Consumer Reporting

PRASCOR is a short message service (SMS) solution for consumer reporting of adverse drug reactions. It is available for free to over 100 million Nigerians using mobile phones on GLO, ETISALAT & MTN networks. Medicine related complaints can freely be sent as text message to the short code 20543while NPC, NAFDAC follows up. About 12,000 of such alerts have been received since 2012.

 The Pharmacovigilance Rapid Alert System for Consumer Reporting (PRASCOR) is a technology driven solution set up by the National Pharmacovigilance Centre, NAFDAC to mitigate the challenge of underreporting of adverse drug reactions (ADRs) in Nigeria as well as address the issue of lack or inadequate awareness especially at the grass roots

How does it work? 

If you ever experience an ADR please text the observed effect to 20543 from your mobile network . Help yourself and help others.

Always read the leaflet on your medicines to know possible adverse and side effects.

What is the difference between Adverse and Side Effect?

Side Effects are symptoms shown by a patient after taking a medication that are a natural consequence of the chemical formula of the drug on the body of the patient. Side effects are mostly anticipated as a drug comes to the market after several trial studies have been conducted and information is most times available in the leaflet in the drug package while Adverse Effects are undesirable effects that are not anticipated. These effects may be harmful for the patient and prompt the doctor to discontinue the administration of the drug. Adverse effects may hamper with the treatment procedure, may complicate the disease or may even worsen the situation or produce a new ailment in the patient.




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Written by StayHealthWise


  1. kanto · October 31, 2014

    Keep it up

  2. Jide Alo · May 30, 2015

    It is one of the leading cause of death among patients. Thanks for sharing.

  3. SANGODIRAN ADEBANJO · June 24, 2015

    Please we are in need of an antedote for paraeforce (paraquat dichloride)

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