Pharmacology

Pharmacology is the study of drugs and how they interact with the body.

• Pharmacokinetics is what the body does to a drug: absorption, distribution, metabolism, and excretion (ADME).
• Pharmacodynamics is what the drug does to the body (its effects and mechanism).
• Key terms include dose, therapeutic range, side effect, and contraindication.
• Drugs come from natural, synthetic, and biologic sources.

Handling medications carries legal and ethical duties.

• Follow the rights of medication administration (right patient, drug, dose, route, time, and documentation).
• Controlled substances are regulated by the DEA and scheduled by abuse potential.
• Maintain confidentiality (HIPAA) and accurate documentation.
• Work within your scope of practice and report errors honestly.

Drug dosing and effects differ at the extremes of age.

• Pediatric doses are usually based on weight (mg/kg) because organs are still developing.
• Geriatric patients often need adjusted doses due to slower metabolism and kidney function.
• Both groups are more sensitive to side effects and interactions.
• Polypharmacy (taking many drugs) is a special concern in older adults.

Drugs are named, grouped, and interact in predictable ways.

• Each drug has a generic name and a brand (trade) name.
• Drugs are grouped into classes by use or mechanism (e.g., analgesics, antibiotics).
• Interactions can be synergistic, antagonistic, or cause adverse effects.
• Knowing a drug's class helps predict its actions and side effects.

Medications are given by different routes, each with trade-offs.

• Enteral routes (oral, sublingual, rectal) use the GI tract.
• Parenteral routes (IV, IM, subcutaneous) bypass the GI tract for faster or more reliable action.
• Topical/transdermal and inhalation are other common routes.
• Route affects onset, absorption, and the first-pass effect through the liver.

Accurate math is essential for safe dosing.

• The metric system (mg, g, mL, L) is the standard in medicine.
• Know common conversions (1 g = 1000 mg; 1 L = 1000 mL).
• Dosage calculations use the formula desired ÷ have × quantity.
• Double-checking calculations prevents dangerous medication errors.

Technology improves medication safety and efficiency.

• Electronic health records and e-prescribing reduce errors.
• Automated dispensing and barcode scanning verify the right drug and dose.
• Drug databases flag interactions and allergies.
• Pharmacogenomics tailors drug choice to a patient's genetics.