Dispensing Lecture

ADR

is a response to a drug that is noxious and unintended, and that occurs at doses NORMALLY used in humans for the prophylaxis, diagnosis or therapy

ADE

An injury resulting from the use of a drug

ADE

includes both preventable and unpreventable ADR errors

ADR

Response to the drug, a noxious and unintended outcome that occurs at doses normally used in human for the prophylaxis, diagnosis or therapy

Pharmaceutical

Pharmacokinetic

Pharmacodynamic

3 causes of ADR

Age

Sex

Race

genetic Influence

Diet and Vices

Multiple medication

Predisposing factors of ADR (patient related) (7)

Dose

Duration of treatment

Inherent Toxicity

Pharmacodynamic properties

Pharmacokinetic properties

Predisposing factors of ADR (Drug-related) (5)

Augmented

Bizarre

Continuous

Delayed

End of Use

Failure of Therapy

6 classification of ADRs

Type A (Augmented)

Common, predictable. Dose related and result directly from the pharmacological action of the drug. Extension effect of drug's pharmacologic action. Side effect, toxicity or overdose. Can be due to drug-drug interaction and drug-food interaction

Type A (Augmented)

Type of ADR

• OHA - hypoglycemia

• Diazepam - sedation

• Loop Diuretics -hypokalemia

• Anticoagulants - bleeding

• Antihistamines - sedation

• Narcotics - constipation

• Paracetamol Overdose -hepatotoxicity

TYPE B (BIZARRE)

Uncommon, unpredictable, more serious than type . Not dose-dependent. Unrelated to drug's pharmacologic action. Often serious and fatal. May be influenced by genetics and environmental factors. Includes both IDIOSYNCRACY and HYPERSENSITIVITY

Type B (Bizarre)

Type of ADR reactions:

● Idiosyncracy - genetically-determined reactions

● Antipsychotic agents - malignant hyperthermia

● Vancomycin (pseudoallergic) - Redman's Syndrome

● Sulfonamides, Phenytoin, Carbamazepine - SJS

● G6PD + Antimalarials or Sulfonamides -Hemolytic Anemia

● Immunologic or Hypersensitivity Reactions - immune responses to environmental antigens resulting in symptomatic reactions upon secondary exposure to the same antigen, more commonly referred to as allergens.

уре 1 (Immediate or Anaphylactic Immune Response )

Most common category of allergic reaction

IgE mediated

e.g. Anaphylaxis from penicilins; hay fever; asthma (NSAID + ASA); urticaria (hives

Туре II (Cytotoxic Reactions)

IgG or IgM mediated

• Blood dyscrasias: disorder of cell components of the blood (Hemolytic anemia, aplastic anemia, thrombocytopenia)

Examples: • Methyldopa -hemolytic anemia

• Chloramphenicol - aplastic anemia

• Aspirin/Ibuprofen - ITP

• Blood transfusion reactions

Туре IlI (Immune Complex

•Serum sickness

• Hydralazine, Isoniazid, Procainamide, Pyrazinamide - Systemic Lupus erythematosus (SLE )

Type IV (Delayed, Cell-mediated)

Delayed reactions (from weeks - months)

• T-cell mediated Examples:

• Tuberculin Skin Test /ROA

• Poison Ivy (urushiol) - Contact Dermatitis

• Tissue/Organ Rejection

TYPE C (CONTINUOUS)

Uncommon. Dose- and time-related. Associated with the cumulative dose of the drug

Addiction

condition where a person takes a drug compulsively, despite ○ potential harm to himself, or his desire to stop

Dependence

compulsion to take the drug repeatedly and experiences unpleasant symptoms if discontinued

Tolerance

increased dose, same response

Tachyphylaxis

- repeated administration, decreased effectiveness

Type D (delayed)

Rare, delayed in onset. Usually dose-related Subtypes: •Carcinogenicity •Teratogenicity

Antineoplastic agents

Aromatic hydrocarbons

Heterocyclic amines

Aflatoxins

Nitrosamines

Carcinogenic agents (5)

pregnancy category A

- no evidence of risk to fetus

Category B

animal studies have failed to demonstrate risk and there are no adequate and well-controlled studies in pregnant women.

Category C

animal studies have shown adverse effects, no adequate well-controlled studies in huma

Category D

positive evidence of human fetal risk but benefits may warrant use.

Category X

positive evidence of human fetal risk and risks outweigh the benefits.

Type E

Uncommon. Withdrawal symptoms

type F (Failure of theraphy)

Common • Dose-related

Patient details

reaction details

reported details

Basic information needed in ADR reporting

1. Critically review the total condition of the patient.

2. Use as few drugs as possible.

3. Know well the drugs that you use.

4. Do not change to readily from one drug you know to one drug you do not know.

5. Do not hesitate to use texibooks and other references providing information on drug reaction and interaction.

6. Be especially careful when prescribing drugs known to exhibit a large variety of reactions and interactions.

7. Be aware of interactions of drugs with certain foods, alcohols, and even with household chemicals.

8. Review all drugs used by your patient regularly.

9. If your patient shows signs and symptoms nol clearly explained by the coarse of Mei iles, think of ADR.

10. If you suspect and ADR, consider stopping the drug or reduce dosage as soon as possible and notify the case to the nearest BFAD/DOH office

10 commandments of ADR