1 Common Adverse Drug Reactions

Separate benefits from unwanted responses

A medication can produce its intended benefit and an unwanted response at the same time. For example, pain may decrease while nausea occurs. Identify each response separately rather than treating every change as either a benefit or evidence of excessive dosing.

Understand therapeutic effects and ADRs

A therapeutic effect is the intended benefit of a medication. Examples include pain relief, reduced blood pressure, less swelling, and improvement in allergy or infection symptoms.

An adverse drug reaction (ADR) is an unwanted, harmful response that occurs at a usual dose. Many common ADRs are predictable from a drug’s known actions, and may become more likely or more troublesome as the dose increases. A predictable side effect is not automatically an emergency, but it still requires assessment and documentation.

Recognize common medication responses

The treatment goal helps distinguish the intended effect from other responses. The following examples illustrate how intended benefits and possible unwanted effects can occur together:

• Opioid for acute pain: Reduced pain is the intended benefit; nausea can be an unwanted effect. Assess how severe and disruptive the nausea is and follow the care plan.

• Diuretic for edema: Reduced swelling is the treatment goal. Increased urination is an expected pharmacologic action of many diuretics, while dry mouth or light-headedness when standing may warrant assessment as unwanted effects.

• Antihistamine for seasonal allergies: Improvement in sneezing is the intended effect; drowsiness is a known unwanted effect of some antihistamines. Assess safety concerns and provide only authorized guidance.

• Beta blocker for hypertension: Reduced blood pressure is intended, but new dizziness may indicate an unwanted response, such as excessive blood-pressure reduction. Assess the patient, including blood pressure and pulse, and report the dizziness according to the care plan and its severity.

• Oral antibiotic for infection: Improvement in infection symptoms is intended; loose stools can be an unwanted effect. Assess and document the symptom, and follow clinical guidance, especially if it worsens or becomes concerning.

Assess, document, and respond

Compare the patient’s response with the medication’s intended effect and assess how bothersome or concerning each response is. Follow the care plan and facility policy, and document findings.

Do not independently change or stop a medication unless authorized by an order or applicable protocol. Escalate promptly if symptoms are severe, worsening, or outside the expected pattern. Do not assume that every symptom is harmless or proof of toxicity; assess the patient and respond according to the circumstances and authorized guidance.