Drug Safety Classifications and Adverse Reaction Monitoring

Fetal Drug Safety Classifications

Type A: These drugs show no apparent risk to the fetus and are considered safe.

Type B: There is no evidence of risk in humans; their use is acceptable during pregnancy.

Type C: Risk cannot be ruled out. These should only be used in situations where there is no other safer drug available.

Type D: There is positive evidence of human fetal risk. These are used only when the drug is needed to treat a serious illness or an extreme situation where no safer alternatives exist.

Type X: These are contraindicated in pregnancy or for women who may become pregnant.

Defining Serious Adverse Drug Reactions (RAM)

What constitutes a serious Adverse Drug Reaction (RAM)? A reaction is considered serious if it:

• Causes death.
• Is life-threatening.
• Requires patient hospitalization.
• Causes disability or invalidity.
• Results in a congenital anomaly.

Risk Factors for Developing Adverse Reactions

Drug-Related Risk Factors

Factors that increase the risk of RAM include:

• The parenteral route of administration.
• High doses and longer duration of treatment.
• Polypharmacy.

Individual-Related Risk Factors

• Age: Older adults, as well as young and middle-aged adults, are more likely to be affected.
• Sex: Females are at a higher risk.
• Genetic predisposition.
• Conditions and Treatments: Malnutrition, hypoalbuminemia, renal and liver function issues, infections, immunodeficiencies, asthma, and treatment with beta-blockers.

Strategies for Preventing Adverse Drug Reactions

To prevent RAM, healthcare providers should:

• Monitor the effects of drugs closely, especially those known for their ability to cause RAM and for people who consume more than three drugs.
• Avoid high-risk drug combinations.
• Choose the oral route of administration whenever possible.
• Question patients thoroughly about previous reactions.

The Role of Pharmacovigilance Systems

A pharmacovigilance system is essential for identifying and quantifying the risk of unwanted effects produced by drugs, as well as identifying factors or characteristics that increase these risks.

Objectives of Pharmacovigilance

• Identify unwanted effects not previously described or unknown.
• Quantify the risk.
• Propose public health measures to reduce incidence.
• Inform prescribers, other health professionals, health authorities, and the public.

Voluntary Reporting of Adverse Reactions

The Voluntary Reporting Program for Adverse Reactions aims to detect unknown ADRs as soon as possible after the marketing of a drug.

Advantages and Limitations of Voluntary Reporting

Advantages:

• Simple method with a rapid detection rate.
• Notification covers the entire population and all drugs from the beginning of marketing.
• Does not interfere with prescription practices.
• Permits the detection of rare adverse reactions.

Limitations:

• Underreporting is the main consequence, leading to decreased sensitivity.
• The reporting rate is not constant, making it impossible to quantify incidence.
• Difficulty in detecting delayed-onset adverse reactions.
• Selection bias, particularly with new drugs.

Causes of Underreporting Among Health Professionals

Why do health professionals fail to report RAM? Common causes include:

• Doubt regarding whether a symptom is worth noticing.
• Doubts about the drug-reaction relationship.
• Workload overload.
• Ignorance of the existence of the notification program.
• Non-availability of "yellow cards" in the workplace.