Biochemistry & Pharmacology: Open Access
Open Access

Causes and Risk Factors Adverse Drug Reactions in Patients

Pirmohamed Mabanckou^{* *}Correspondence: Pirmohamed Mabanckou, Department of Pharmacology and Therapeutics, University of Liverpool, Liverpool, England, Email:

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About the Study

Adverse Drug Reactions (ADRs) are a significant concern in healthcare, as they can lead to patient harm, increased healthcare costs, and even fatalities. ADRs occur when a patient experiences unexpected and harmful effects from a medication, and they can range from mild and tolerable side effects to severe, life-threatening reactions. Understanding ADRs, their causes, prevention strategies, and management is crucial for healthcare professionals, patients, and the pharmaceutical industry.

Adverse Drug Reactions (ADRs)

An ADR, also known as a side effect, is an undesirable and unintended response to a medication that occurs at therapeutic doses. These reactions can affect various organs and systems in the body and may be caused by the medication itself, its metabolites, or interactions with other drugs or substances. ADRs can manifest as a wide range of symptoms, from mild gastrointestinal discomfort to severe allergic reactions or organ damage.

Types of adverse drug reactions

Type A reactions (Predictable): These are the most common ADRs and occur in a dose-dependent manner. They are typically related to the known pharmacological actions of the drug. For example, gastrointestinal upset with Nonsteroidal Anti- Inflammatory Drugs (NSAIDs) or bleeding tendencies with anticoagulants fall into this category.

Type B reactions (Idiosyncratic): These are less common and often unpredictable. They do not correlate with the drug's known pharmacological actions and are thought to result from individual patient factors, such as genetics or immune system reactions. Examples include severe allergic reactions or druginduced liver injury.

Type C reactions (Chronic): These reactions occur with longterm drug use and may not become apparent until months or years after initiation. For instance, osteoporosis due to chronic corticosteroid use or tardive dyskinesia from antipsychotic medications.

Type D reactions (Delayed): Delayed ADRs may take weeks or even months to manifest. Examples include drug-induced cancers or delayed hypersensitivity reactions.

Type E reactions (End of use): These reactions occur when a medication is discontinued and may involve withdrawal symptoms or rebound effects. An example is the discontinuation of certain antidepressant medications leading to withdrawal symptoms.

Causes and risk factors

Several factors contribute to the development of ADRs:

Patient factors: Individual patient characteristics, such as age, genetics, sex, and underlying health conditions, can influence susceptibility to ADRs.

Drug factors: The drug's pharmacological properties, dosage, route of administration, and potential for interactions with other drugs can impact the likelihood of ADRs.

Polypharmacy: The concurrent use of multiple medications increases the risk of drug interactions and ADRs.

Comorbidities: Patients with multiple medical conditions may be more vulnerable to ADRs due to complex drug regimens.

Prevention of adverse drug reactions

Preventing ADRs is a critical goal in healthcare. Strategies to minimize the risk include:

Medication review: Regularly reviewing a patient's medication list to identify potential interactions or unnecessary drugs.

Patient education: Providing patients with information about their medications, including potential side effects and what to do if they experience them.

Monitoring: Regular monitoring of patients on high-risk medications or those with known potential for ADRs, such as regular liver function tests for patients on certain drugs.

Dose adjustment: Individualizing drug dosages based on patient factors, such as age, weight, and kidney function.

Avoiding polypharmacy: Reducing the number of medications whenever possible, especially in older adults.

The role of patients

Patients also play a vital role in preventing and managing ADRs. They should:

Be informed: Understand the medications they are taking, including potential side effects.

Communicate: Inform healthcare providers about any past ADRs, allergies, or unusual symptoms they experience while on medication.

Adhere to medication plans: Follow prescribed medication regimens carefully, including dosages and schedules.

Adverse drug reactions are a complex and multifaceted issue in healthcare. While they cannot always be entirely prevented, a proactive approach involving healthcare providers, patients, and regulatory agencies can significantly reduce the occurrence and severity of ADRs. Ensuring medication safety is an ongoing process that requires vigilance, education, and a commitment to improving patient outcomes while minimizing harm. Through continued research, pharmacovigilance, and patient engagement, the medical community can work together to make medication use safer and more effective for all.