Drug Side Effects and Adverse Reactions

Differential Diagnosis

Distinguishing between related concepts for drug side effects and adverse reactions:

SSRIs: Examples: sertraline, fluoxetine, escitalopram, paroxetine. Mechanism: Selectively inhibit serotonin reuptake in synaptic cleft, increase 5-HT activity. Key side effects: GI upset (nausea); Sexual dysfunction.

ACE inhibitors: Examples: lisinopril, enalapril, ramipril. Mechanism: Block angiotensin-converting enzyme, decrease angiotensin II, cause vasodilation and decreased aldosterone. Key side effects: Dry cough (10-15%); Hyperkalemia.

Overview

Unintended effects from common (nausea, dizziness) to serious (anaphylaxis, hepatotoxicity, QT prolongation). Recognizing side effects and adverse reactions tested on PTCB exam.

Related drug class: Beta blockers includes metoprolol, atenolol, propranolol, carvedilol. Mechanism: Block beta-adrenergic receptors, decrease heart rate and contractility.

Historical Context

Pharmacy regulation in the U.S. began with the Pure Food and Drug Act of 1906. The Federal Food, Drug, and Cosmetic Act of 1938 required proof of safety. The 1962 Kefauver-Harris Amendment added efficacy requirements. Understanding drug side effects and adverse reactions within this regulatory history helps pharmacy technicians appreciate why current standards exist, as each major regulation was prompted by a public health crisis.

Assessment Techniques

Unintended effects from common (nausea, dizziness) to serious (anaphylaxis, hepatotoxicity, QT prolongation). Recognizing side effects and adverse reactions tested on PTCB exam.

Related drug class: Opioids includes morphine, hydrocodone, oxycodone, fentanyl, codeine. Mechanism: Bind mu-opioid receptors for analgesia, euphoria, respiratory depression.

Common Errors

Frequent errors with drug side effects and adverse reactions in pharmacy practice:

1. Misreading sig codes. For reference: OU = both eyes; TOP = topically; PRN = as needed; QD = once daily; QHS = at bedtime; OD = right eye
2. Calculation errors in dosage. Always double-check units (mg vs mcg, mL vs L)
3. Wrong DEA schedule classification affecting storage and dispensing requirements

Equipment & Tools

Unintended effects from common (nausea, dizziness) to serious (anaphylaxis, hepatotoxicity, QT prolongation). Recognizing side effects and adverse reactions tested on PTCB exam.

Related drug class: Insulins includes lispro (rapid), regular (short), NPH (intermediate), glargine (long). Mechanism: Replaces endogenous insulin, facilitates glucose uptake into cells.