When an IV infiltrates, the medication itself becomes the difference between mild irritation and catastrophic tissue injury.
Many hospitals use a Red/Yellow/Green (RYG) categorization system to classify IV medications based on the potential harm that could occur if a drug leaks outside the vein. This system is a widely adopted clinical tool for stratifying the risk of tissue injury from IV infiltration or extravasation. Its purpose is to help clinicians quickly anticipate the potential severity of harm; however, the rationale behind each category—and the mechanisms by which these agents cause damage—are often overlooked.
Understanding the RYG system is essential because not all infiltrations or extravasations carry the same risk. The medication itself often determines whether the outcome will be limited to minor swelling or result in significant tissue injury. The RYG framework offers a clear, practical way for clinicians to recognize why certain drugs pose greater danger outside the vein and to adjust their practice accordingly. For example, by understanding a drug’s pH or osmolarity and other properties, clinicians can anticipate whether it should be categorized as Red (high risk), Yellow (moderate risk), or Green (lower risk). With this knowledge, clinicians can take appropriate precautionary actions—such as increasing the frequency of site assessments or using continuous patient monitoring technologies—based on the anticipated severity of harm associated with each drug.
Drug pH Equivalents
Extreme pH levels—whether highly acidic or alkaline—can cause the most severe tissue damage. Imagine the harmful effects if substances like bleach or stomach acid were to leak into the delicate tissue beneath your skin.
Vesicant drugs represent the highest-risk category of IV medications, as they can cause severe tissue injury and even necrosis if extravasation occurs.
These agents fall into four main groups:
- Hyperosmolar Solutions: Solutions with osmolarity greater than 600 mOsm/L.
- Non-physiological pH: Solutions with an acidic pH below 5 or an alkaline pH above 9.
- Vasopressors: Agents such as adrenaline, noradrenaline, and dopamine.
- Chemotherapy Agents: Particularly anthracyclines.
Because of their potential for extreme tissue harm, vesicant drugs should be administered through a central vein whenever possible. In contrast, non-vesicant drugs and solutions can be administered via a peripheral vascular access device placed in a peripheral vein.
Studies suggest that hyperosmolar solutions above 600 mOsm/L; (normal range 285-310) (Pittiruti et al 2023 Manrique-Rodríguez et al 2021), extremely acidic or basic pH(<5 or >9), cytotoxic and vasoconstrictive drugs are associated with a higher risk of subsequent leakage and tissue damage when given peripherally (Couissi et al 2023;David et al 2020).
RED CATEGORY: Severe Injury Risk
Medications in this group are vesicants or highly irritant solutions capable of causing tissue necrosis, severe chemical burns, neurovascular injury, or compartment syndrome if extravasation occurs. Many require the use of specific antidotes and immediate clinical escalation.
These agents often possess one or more of the following characteristics:
- Extremely high osmolarity
- Non-physiological pH (acidic or alkaline solutions that destroy tissue)
- Direct cytotoxic effects on cells
- Vasoconstrictive properties that reduce or cut off local blood flow
- Hypertonic formulations that draw fluid out of cells, worsening edema and cellular injury
Examples of Vesicant and Highly Irritant Medications
YELLOW CATEGORY: Intermediate Risk, Still Dangerous
Yellow-list medications are considered irritants—not vesicants—but can still cause significant harm. They often create localized inflammation, but in pediatrics, even “intermediate” drugs can escalate quickly.
Examples of Irritant and Intermediate-Risk Medications
GREEN CATEGORY: Lower Risk — But, Not Harmless
Green-category medications are generally associated with a lower risk of tissue injury; however, infiltrations are not without consequence. With sufficient volume, infusion pressure, or delayed recognition, even these agents can result in significant harm. For example, normal saline infused rapidly under pressure can cause compartment syndrome, particularly in small children.
Examples of Low-Risk and Less Irritant Medications
No intravenous infusate is “safe”.
Gross extravasation, even of normal saline, may result in serious harm including compartment syndrome, causing ischemia and loss of tissue or permanent loss of limb function. https://www.cincinnatichildrens.org/service/v/vascular-access/hcp
Why Understanding RYG/RAG Is Essential
Extravasation risk depends on multiple factors beyond just the drug name, including osmolarity, pH, vesicant properties, volume, infusion duration, and patient vascular fragility. Understanding these risks allows clinicians to select safer access routes, monitor IV sites proactively, and intervene early to prevent injury.
Key Risk Factors:
- Osmolarity
- pH
- Vesicant vs. irritant properties
- Volume infused
- Infusion duration
- Vascular fragility (pediatrics, oncology, elderly)
Complications of Extravasation:
- Pain, swelling, redness
- Blistering, tissue necrosis
- Nerve injury, infection
- Ischemia, functional impairment
- Amputation, death (in extreme cases)
Continuous IV Monitoring
By combining thorough risk assessment with continuous IV site monitoring, clinicians gain a critical early-warning system that can detect infiltrations and extravasations often before visible signs of tissue injury appear.
The ivWatch system provides real-time alerts, enabling clinicians to make timely interventions to reduce patient harm, and improve outcomes across all care settings. By adding this layer of technology, healthcare teams can proactively safeguard patients, optimize IV therapy, and enhance overall safety and confidence in infusion management.
Discover how ivWatch technology can seamlessly integrate into your facility to elevate patient safety and transform IV care.
Learn more about technology and causes of infiltrations/extravasations.