Eco-Pharmacovigilance

Eco-Pharmacovigilance (Eco-PV) is a critical and emerging field that extends the principles of pharmacovigilance from human safety to environmental safety.

In simple terms, while traditional PV asks, “Is this drug safe for the patient?”, Eco-PV asks, “Is this drug safe for the environment?”

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What is Eco-Pharmacovigilance?

It is the science and activities devoted to the detection, assessment, understanding, and prevention of adverse effects of pharmaceuticals on the environment, with the goal of maintaining ecosystem health.

The Core Problem: How Do Drugs Get into the Environment?

Pharmaceuticals are designed to be biologically active. After use, they enter the environment through a complex pathway:

1. Human Excretion: Patients metabolize drugs, but often a significant portion is excreted unchanged or as active metabolites through urine and feces.
2. Improper Disposal: Flushing unused or expired medications down the toilet or sink is a direct route.
3. Agricultural Runoff: Manure from livestock treated with antibiotics and hormones is used as fertilizer, which can wash into rivers and streams.
4. Wastewater Treatment Plants (WWTPs): These plants are not designed to remove all the complex synthetic chemicals found in pharmaceuticals. As a result, many drugs pass through untreated and are released into rivers and lakes.

What are the Consequences? (The “Adverse Events” for the Environment)

The continuous release of pharmaceuticals creates a low-level but constant exposure for wildlife, with documented effects:

• Hormonal Disruption: Estrogens from birth control pills have caused feminization of fish (male fish developing female characteristics), leading to reproductive failure and population decline.
• Antibiotic Resistance: The release of antibiotics into the environment is a major driver of antimicrobial resistance (AMR). It creates selective pressure, allowing resistant bacteria to survive and multiply, creating environmental reservoirs of “superbugs.”
• Toxicity to Wildlife: Anti-inflammatory drugs like diclofenac have been devastating for vulture populations in Asia (causing kidney failure). Antidepressants can alter the behavior of fish and other aquatic organisms.
• Effects on Ecosystems: These disruptions can ripple through the food web, affecting biodiversity and ecosystem stability.

Key Activities in Eco-Pharmacovigilance

Eco-PV adapts the classic PV cycle to the environment:

1. Detection & Monitoring:
   • Environmental Monitoring: Systematically testing water (surface water, groundwater, drinking water), soil, and sediment for pharmaceutical residues.
   • Biological Monitoring: Examining wildlife for physiological or behavioral changes.
2. Risk Assessment:
   • PEC/PNEC Comparison: A common method involves comparing the Predicted Environmental Concentration (PEC) with the Predicted No-Effect Concentration (PNEC). If PEC > PNEC, there is a potential risk.
   • Assessing the persistence (how long it lasts) and bioaccumulation potential of a drug.
3. Risk Management & Prevention:
   • Green Pharmacy: Designing new drugs to be more biodegradable or less environmentally persistent right from the R&D stage.
   • Improved Waste Management: Promoting take-back programs for unused medications and improving wastewater treatment technologies (e.g., advanced oxidation, activated carbon filters).
   • Regulatory Action: Some regions are now requiring environmental risk assessments (ERA) as part of the drug marketing authorization process.
   • Public Awareness: Educating the public and healthcare professionals not to flush medications.

The Link to Human Health

Eco-PV is not just about saving fish. It has a direct feedback loop to human health:

• Antibiotic Resistance: Environmental AMR genes can be transferred to human pathogens, rendering our life-saving antibiotics ineffective.
• Contaminated Drinking Water: Pharmaceuticals can enter drinking water sources, leading to chronic, low-level human exposure to a mixture of drugs, the effects of which are largely unknown.

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This is an official European Medicines Agency (EMA) guideline that outlines the process for conducting an Environmental Risk Assessment (ERA) for human medicinal products. It came into effect on 1 September 2024, replacing the previous version. The purpose is to evaluate the potential risks that a medicine’s active substance(s) may pose to the environment after use by patients.

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Key Concepts Explaine

1. When is an ERA Required?

• It is mandatory for all new Marketing Authorisation Applications (MAAs) submitted through any procedure (centralised, national, etc.).
• It is also required for certain post-authorisation changes (Type II variations, extensions) if they are expected to increase environmental exposure (e.g., a new indication, higher dose, new route of administration).
• It is not required for the renewal of a marketing authorisation.

2. The Two Main Components of an ERA
The ERA consists of two parallel assessments:

• Risk Assessment: Evaluates the potential for harmful effects based on predicted exposure levels (PEC – Predicted Environmental Concentration) and toxicity (PNEC – Predicted No-Effect Concentration). If PEC/PNEC ≥ 1, a risk is identified.
• PBT/vPvB Assessment: A hazard-based assessment to identify substances with intrinsic dangerous properties, regardless of exposure. It checks for:
  • Persistence (does not break down easily).
  • Bioaccumulation (builds up in organisms).
  • Toxicity.
  • vP and vB are “very” persistent and bioaccumulative.

3. The Phased and Tiered Approach
The ERA follows a stepwise, tiered approach to avoid unnecessary testing.

Phase I: Initial Screening

• Goal: To identify products that need a detailed assessment.
• Process: A decision tree is used. The key step is calculating a Predicted Environmental Concentration in surface water (PEC_SW) using default, worst-case assumptions.
• Outcome:
  • If the PEC_SW is below 0.01 µg/L and no other concerns exist, the ERA stops.
  • Exceptions: Some substances (like Endocrine Active Substances – EAS and antiparasitics) must proceed to Phase II regardless of their PEC due to their high potency.

Phase II: Detailed Assessment

This phase is divided into two tiers:

• Tier A (Standard Data Set): Requires a base set of data on the substance’s properties:
  • Physico-chemical properties (e.g., water solubility, partition coefficient).
  • Environmental fate (e.g., biodegradability, adsorption to soil/sludge).
  • Ecototoxicity (chronic tests on algae, daphnia, and fish).
  • Based on this data, risk is assessed for various compartments: surface water, sediment, sewage treatment plant (STP) functioning, soil, groundwater, and secondary poisoning (risks to predators eating contaminated prey).
• Tier B (Refinement): If a risk is identified in Tier A (PEC/PNEC ≥ 1), the applicant can refine the assessment. This can involve:
  • Using more realistic exposure data (e.g., actual market penetration, metabolism in humans, removal in STPs using the SimpleTreat model).
  • Conducting further, more specific ecotoxicity tests.

4. Tailored Strategies for Specific Substances
The guideline provides specific testing strategies for substances with particular modes of action:

• Antibacterials: The ecotoxicity testing focuses on lower trophic levels (bacteria, algae, invertebrates) and may waive the fish test.
• Endocrine Active Substances (EAS): These always require a Phase II assessment. The testing strategy uses specialized, long-term fish or amphibian tests that can detect effects on development and reproduction.

5. Data Requirements and Animal Welfare

• The guideline emphasizes the 3Rs principles (Replacement, Reduction, and Refinement of animal testing).
• Applicants are encouraged to use existing data, share data with other companies, and conduct thorough literature reviews to avoid repeating tests.
• Studies should preferably follow OECD test guidelines and be conducted under Good Laboratory Practice (GLP).

6. Outcome and Risk Mitigation

• If a risk is identified or the substance is classified as PBT/vPvB, this information must be included in the Summary of Product Characteristics (SmPC) and the Package Leaflet (PL).
• Risk mitigation measures are required, which typically involve advising patients on the proper disposal of unused medicines to prevent them from entering the environment via wastewater.

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Eco-Pharmacovigilance represents the necessary evolution of drug safety into the 21st century. It acknowledges that the environmental impact of pharmaceuticals is an unintended, but serious, “adverse effect” of modern healthcare. By integrating Eco-PV into the drug lifecycle, we can work towards a more sustainable and truly “One Health” approach, protecting both ecosystems and human populations for the long term