Pharmacology and Medication Administration
Drug Basics
Pharmacology covers how drugs work and how they are safely given. Know classification (analgesic, antibiotic, antihypertensive, antiemetic), routes (oral, sublingual, topical, inhalation, subcutaneous, intramuscular, intravenous, rectal), forms, and basic pharmacokinetics - absorption, distribution, metabolism, and excretion. Most metabolism occurs in the liver and most excretion in the kidneys.
Concepts to Master
- Six rights: right patient, drug, dose, route, time, and documentation. Many settings add right reason and right to refuse.
- Abbreviations: PO (by mouth), SL (sublingual), IM (intramuscular), SubQ (subcutaneous), PR (rectal), q.d. (daily), q.i.d. (four times daily), PRN (as needed), NPO (nothing by mouth).
- Documentation: drug, dose, route, site, time, and response. Report adverse reactions and errors.
- Controlled substances: secure storage, counting, and required records.
- Patient teaching: purpose, common side effects, and when to call.
Traps
Questions target unsafe abbreviations and decimal errors. Always use a leading zero (0.5 mg) and never a trailing zero (5 mg, not 5.0 mg). Do not confuse mg with mcg. Verify allergies before administration. Never administer a drug prepared by someone else without verification, and never guess an illegible order - clarify it.
Worked Example
Order: 250 mg. Available: 500 mg tablets. Use desired ÷ available × quantity: 250 ÷ 500 × 1 = 0.5 tablet. Because half a tablet may not be acceptable, clarify with the provider. Rule of thumb: check the calculated dose against the order and a safe range before giving anything.