Adverse drug reactions of medicinal products

Introduction

• Adverse drug reactions are the responses to medicinal products that are harmful and unwanted. They occur at doses given to humans for therapy or prophylaxis or for change in physiological action.
• Serious adverse reactions are the responses of a drug given at any amount of dose which causes death or threatens life requiring hospitalization or resulting in damage permanently.
• Unexpected adverse drug reactions are the reactions that occur whose severity is not mentioned in the prescribing information or market authorization form.

Types of adverse drug reactions

During administration of medicines adverse reaction occur due to physical, chemical or biological nature of formulation. Adverse reactions may result due to co administration with other drugs or as a result of systemic effects, allergic reactions or local toxicity and irritation from local therapies or from unknown sources in few individuals. In case when attributes of formulation are unknown then adverse reactions can be the result of any ingredient. In vivo it was found that even when all the ingredients are listed still there are chances for unwanted effects which can be unpredictable.

Classification

Adverse drug reactions are classified into type A, B, C, D and E reactions.

Type A reactions are the result of an exaggerated response of drug’s intended pharmacological response and this response is normally dose dependent. 80% of adverse reactions constitute type A reaction.

Type B reactions are also called bizarre reactions as they are unexpected or unintended reactions from a drug pharmacological action.

Type C reactions are the adverse reactions that persist for longer time.

Type D reactions are the delayed reactions that are evident only after some time of taking medicine.

Type E reactions are also called End of use reactions as they show up after the stopping or withdrawal of medication. 

Adverse reactions, toxicity, allergic reactions

• uchegbu if, florence at. adverse drug events related to dosage forms and delivery systems. drug saf. 1996 jan;14(1):39-67.
• guidelines for monitoring and reporting adverse drug reactions (adrs). the united republic of tanzania ministry of health. http://apps.who.int/medicinedocs/documents/s18571en/s18571en.pdf. published january 2006. accessed may 2016.
• guidance on adverse drug reactions. https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/403098/guidance_on_adverse_drug_reactions.pdf. accessed may 17, 2016.