ADVERSE DRUG REACTION CLASSIFICATION

 Introduction

    

• A drug is a single active chemical entity present in a medicine that is used for the diagnosis, prevention, and, treatment of diseases. (Mererjone, 2003). Adverse drug reaction is the unexpected effect of drugs on animals and humans and is considered one of the causes of morbidity and mortality in hospitalized patients (Ditto, 2004).

• An adverse drug reaction (ADR) can be defined as ‘an appreciably harmful or unpleasant reaction resulting from an intervention related to the use of a medicinal product.

• Adverse effects usually predict hazards from future administration and warrant prevention, specific treatment, alteration of the dosage regimen, or withdrawal of the product’. 

             

1. What is an adverse drug event (ADE)? 

          An adverse drug event is defined as “an injury resulting from the use of a     drug. By this definition, the term ADE includes harm caused by drugs (adverse drug reactions and overdoses) and harm resulting from the use of the drug (Including weight loss and drug discontinuation), but most do not.

2. What is an adverse drug reaction (ADR)? 

An adverse drug reaction is defined as a “response to a drug which is noxious and unintended and which occurs at doses normally used in man for prophylaxis, diagnosis, or treatment of disease or the improving of physiologic function.” Note that there is a causal link between a drug and an adverse drug reaction.

Classification of adverse drug reactions

Adverse drug reactions are classified as Type A & Type B. An extended version of this classification system is shown here:

Type A Reactions 

Type A (augmented) reactions result from an exaggeration of a drug’s normal pharmacological actions when given at the usual therapeutic dose and are normally

dose-dependent ADR. Examples are respiratory depression that may occur with opioid drugs or bleeding when we take warfarin.

Type B Reactions 

Type B reactions (strange) are new, unexpected reactions based on the known pharmacological effects of a drug. Because these are rarer, they may not be discovered until drugs are generally available.

Examples include anaphylaxis due to penicillin or skin rash due to antibiotics.

Type C- Reactions 

Type C or “persistent” reactions are long-lasting. An example is bisphosphonate-induced osteonecrosis of the jaw.

Type D Reactions 

Type D or “delayed” reactions occur sometime after the use of the drug. These timings can make them difficult to find. An example is leukopenia, which can occur within 6 weeks of lomustine administration.

Type E Reactions 

Type E or end-of-use reactions are associated with

drug discontinuation. One example is insomnia, anxiety, and cognitive impairment after withdrawal from benzodiazepines.

Classification of ADR

Type of reaction	Feature	Example	Management
A: Dose-related (Augmented)	Common Related to the pharmacologic action of the drug – exaggerated pharmacologic response Predictable Low mortality	Dry mouth with tricyclic antidepressants, respiratory depression with opioids,	Reduce dose or withhold drug Consider effects of concomitant therapy
B: Non–dose-related (Bizarre)	Uncommon Not related to the pharmacologic action of the drug Unpredictable High mortality	Immunologic reactions: anaphylaxis to penicillin Idiosyncratic reactions:	Withhold and avoid in future
C: Dose-related and time-related (Chronic)	Uncommon Related to the cumulative dose	Hypothalamic-pituitary-adrenal axis suppression by corticosteroids, osteonecrosis of the jaw with bisphosphonates	Reduce dose or withhold; withdrawal may have to be prolonged
D: Time-related (Delayed)	Uncommon Usually dose related Occurs or becomes apparent sometime after the use of the drug	Carcinogenesis Tardive dyskinesia Teratogenesis Leucopenia with lomustine	Often intractable
E: Withdrawal (End of use)	May occur after withdrawal of therapy or use of drug	Withdrawal syndrome with opiates or benzodiazepines (e.g., insomnia, anxiety)	Reintroduce the drug and withdraw slowly
F:  failure of therapy (Failure)	Dose-related may caused by drug interactions	Inadequate dosage of an oral contraceptive when used with an enzyme inducer.	Increase dosage Consider the effects of concomitant therapy

Conclusion and recommendation
Adverse drug reactions are one of the causes of morbidity and mortality in animals and humans. Industries manufacturing drugs should monitor ADR and try to reduce it by various withholding, withdrawal, and reduction in dosage.  Treatment should be given as soon as ADR Occur. Improve ADR Monitoring.

• Non-Hcpcp & Non-Hcp should be trained in diagnosis and management.

• The ADR data should be transferred to another country.

• Companies should try to reduce the side effects of their drug.

• More studies should be done in the area of ADR 

References

• Edwards IR, Aronson JK. Adverse drug reactions: definitions, diagnosis, and management. Lancet 2000;356:1255-9.

• Ditto, A.M. (2004): Drug allergy: In (Grammer, L.C and Greenberger, P.A.) Eds.Patterson’s allergic diseases.

          6th ed. Philadelphia: Lippincott Williams & Wilkins. p. 295.

•  Nebeker JR, Barach P, Samore MH. Clarifying Adverse Drug Events: A Clinician’s Guide to Terminology, Documentation, and Reporting. Ann Intern Med. 2004; 140:795-801.

 

WRITTEN BY

Name: Amol Kharat
Qualification: m. pharm
 ID: 133/0722

 Email Id: amolkharat2507@gmail.com