3 Drug Toxicity and Overdose
Learn how medication toxicity develops, recognize warning signs and risk factors, and respond safely to suspected toxicity and overdose.
How toxicity develops
occurs when a medication’s effects become harmful. It may follow an overdose or medication error, but it can also develop during prescribed use. For example, a drug may accumulate when kidney or liver function declines, an interacting medicine is added, or fluid and electrolyte changes alter the drug’s effects.
Risk is increased by older age, taking multiple medications, dosing mistakes, and impaired drug clearance. Taking multiple products that contain the same active ingredient can also increase risk. Following the prescribed dose and monitoring plan is not itself a risk factor; monitoring can help identify problems.
Recognizing warning signs
Possible warning signs include new confusion or unusual drowsiness, weakness, tremor or poor coordination, nausea and vomiting, vision changes, abnormal heart rate, reduced urine output, seizures, or difficulty breathing. The pattern depends on the medication, and some dangerous overdoses cause few or no early symptoms.
Do not wait for symptoms to appear before seeking help when a potentially serious exposure is suspected. A person may feel well after taking too much acetaminophen even when serious liver injury is possible.
Responding to suspected toxicity
A nurse who suspects toxicity should promptly assess airway, breathing, circulation, level of consciousness, vital signs, and relevant symptoms. In an acute-care setting, withhold a suspected next dose while urgently seeking clinical direction, notify the responsible clinician, and activate the emergency response for instability.
Obtain details about the medication, dose, route, and timing. Review relevant laboratory results and monitoring records, and anticipate medication-specific tests or treatment under orders and local protocol. Document findings and actions, and report medication errors according to facility policy.
Do not induce vomiting. Do not delay help while waiting for symptoms. In the United States, call 911 for collapse, seizure, trouble breathing, or inability to awaken. For a suspected exposure without those emergency signs, contact at 1-800-222-1222.
Safeguards and escalation
deserve particular attention because an error can cause serious harm. Use required safeguards and medication-specific monitoring rather than relying on a single symptom or laboratory value.
In suspected , escalate promptly and follow clinician direction about further doses and monitoring. Emergency services are appropriate for life-threatening signs; can provide guidance for suspected exposures without those emergency signs.
Digoxin and
A patient taking digoxin develops nausea, poor appetite, yellow-green visual changes, and an irregular pulse, while kidney function has worsened. These findings can indicate possible . The appropriate response is to assess the patient, withhold the next dose pending urgent clinical direction, and promptly notify the prescriber—not to reassure the patient and give another dose or treat symptoms in isolation.
Kidney function and electrolyte status are relevant to the assessment. The clinician may order an ECG and tests such as a digoxin level, kidney function, potassium, and magnesium.
Vomiting and diarrhea followed by a coarse tremor, unsteady gait, and slurred speech in a patient taking lithium are concerning for . Obtain urgent clinical assessment and follow clinician direction about further doses and monitoring. Fluid loss and interacting medicines can contribute to risk.
Suspected
If a patient may have taken too much acetaminophen but feels well, seek poison-exposure guidance immediately rather than waiting for abdominal pain or jaundice. Early may cause few or nonspecific symptoms even when serious liver injury is possible. Do not induce vomiting or delay care while waiting for symptoms.
Suspected
Difficulty awakening and slow, shallow breathing after taking an opioid are emergency signs of possible . Call 911 immediately, support breathing as trained, and give if available, following its instructions. Continue emergency support and follow dispatcher instructions.