Adverse Drug Reaction – Pharmacology – mimprovement

Adverse Drug Reaction

Adverse drug reaction is an undesirable effect of drug in our body which we don’t want. It may include all kind of noxious effect such as trivial, serious, even portal. In the other word, any unwanted medical occurrence that may present during treatment with medicine, but which may not have causal relationship with the treatment. Adverse drug reactions (ADRs) are one of the most common and serious complications of medications. ADRs can cause a wide range of symptoms, from mild to severe, that may significantly impact a person’s quality of life. Adverse effects may develop instantly or only after prolonged modification or even after stoppage of the drugs.

Common causes of adverse drug reaction

1. Overdosing
2. Falling to take the correct doses at the correct time.
3. Allergy to chemical components of the medicine.
4. Combining the medicine with alcohol.
5. Taking after drugs or preparations that interact with the medicine.
6. Taking a medicine that was prescribed for someone else.

Factor affecting adverse drug reactions

1. Age
2. Sex
3. Genetic influences
4. Concurrent diseases (renal, liver, cardia)
5. Previous adverse drug reaction
6. Compliance with dosing regimen
7. Total number of medications
8. Misc. (diet, smoking, environmental exposure)

Types of adverse drug reactions

Adverse drug reactions are classified into six types:

1. Type-A or Augmented
2. Type-B or Bizarre
3. Type-C or Continuous
4. Type-D or Delayed
5. Type-E or Ending of use
6. Type-F or Failure of efficacy

1. Type-A reaction

It is also known as augmented. This reaction occurs in the case when amount of drug is increase in body. This type of adverse drug reaction can be minimized by using of adjustment or other combination of drug. This type of reaction allows for the synthesis of molecules from two different starting materials with no need for a catalyst. This process can be carried out at room temperature, making it one of the most efficient and cost-effective ways to produce substances.
Example:- Benzodiazepines – Sedation, Furosemide – Water and electrolyte imbalance, Insulin – Hypoglycemia.

2. Type-B reaction

It is also known as bizarre reaction. This type of reaction occurs suddenly with unknown reason and effect of drug is not known. It includes allergy and idiosyncrasy. They are less common, often non-dose related, generally more serious and require withdrawal of drugs. It is unpredictable.
Example:- Allergy due to hypersensitivity, Idiosyncrasy and Hemolytic etc.

3. Type-C reaction

It is also called Continuous reaction. Those types of adverse drug reaction which was appear in human body by taking continuous dose of any drug for long duration is called type-c adverse drug reaction. Long term effects are usually related to the dose and duration of treatment.
Example:- Ethambutol – Retinopathy, NSAIDS – Nephrotoxicity.

4. Type-D reaction

This reaction is also called Delayed reaction. In this type of adverse drug reaction, the adverse effect of drug will be delayed after the prolong use of any medication.
Example:- Carcinogenesis, Teratogenesis, Thalidomide

5. Type-E reaction

This reaction is also called end of use reaction. This type of adverse drug reaction occurs when we suddenly stop use of any drug which we take from a long time. This type of effects appears after ending of any medication.
Example:- Angina after atenolol, Rebound hypertension after clonidine etc.

6. Type-F reaction

This type of adverse drug reaction is certain and this is basically failure of efficiency. In this type of reaction, the drug can’t show their own response.
Example:- Counterfeit medicines, Underdosing of medications and Drug interactions.

Prevention of adverse effects to drugs

It can be minimized but not eliminated:-

1. Avoid all inappropriate use of drugs.
2. During medication, consider pervious history of drug reaction.
3. Check history of allergic disease.
4. Rule out possibility of drug interaction, when more than one drug is prescribed.

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