drugs

Here’s a clear, concise summary of your “Pharmacology Basics” text — organized by key concepts and main ideas:

Pharmacology Basics Summary

Drugs go through three main phases:

1. Pharmaceutics – How the body uses the drug form
   

   • Applies mainly to oral (PO) drugs.

   • Disintegration: Solid meds break down into smaller particles.

   • Dissolution: Particles dissolve into liquid form for absorption.

   • Drugs that take longer to dissolve should be given first; “ready-to-use” drugs can be given last.

2. Pharmacokinetics – What the body does to the drug
   Has four stages: absorption, distribution, metabolism, excretion.
   

   • Absorption:
     

     • Drug enters body fluids by passive, active, or pinocytosis transport.

     • Affected by food, stress, age, organ maturity, and blood flow.

     • Hepatic first-pass effect: Some oral drugs are broken down by the liver before entering circulation → reduces drug amount reaching bloodstream (bioavailability).

     • IV drugs = 100% bioavailable.

   • Distribution:
     

     • Drugs travel through bloodstream; often bind to proteins.

     • Free (unbound) drug = active; bound = inactive (storage form).

     • Low protein levels → more free drug → higher risk of toxicity.

   • Metabolism (Biotransformation):
     

     • Mainly occurs in the liver.

     • Half-life: Time it takes for half of the drug to be eliminated → determines dosing frequency.

     • Monitor AST and ALT for liver function.

   • Excretion:
     

     • Mainly through kidneys; also lungs, sweat, and feces.

     • Impaired kidney function → drug accumulation and toxicity.

     • Monitor BUN, creatinine, GFR, and creatinine clearance.

3. Pharmacodynamics – What the drug does to the body
   

   • Primary effect: Intended/therapeutic.

   • Secondary effect: May be desirable or undesirable (e.g., Benadryl causes drowsiness).

   • Onset: Time to start working.

   • Peak: Time of maximum effect.

   • Duration: How long effects last.

   • Nonspecific drugs: Act on one receptor that affects multiple organs.

   • Nonselective drugs: Act on multiple receptor types → more side effects.

Drug Safety and Monitoring

• Therapeutic Index (TI): Safety margin of a drug. Narrow TI = higher risk of toxicity → monitor blood levels.
  

  • Peak level: Highest concentration.

  • Trough level: Lowest concentration.

  • Loading dose: Extra initial dose to reach therapeutic level quickly.

• Side effect: Mild undesired result (e.g., constipation).

• Adverse effect: Severe, dangerous reaction → stop drug.

• Toxic effect: From overdose or organ failure → drug buildup.

Body Surface Area (BSA)

Used to calculate drug doses, burns, and fluid needs.

Formula:

BSA = \sqrt{\frac{height (cm) \times weight (kg)}{3600}}

Patient Safety & Rights of Medication Administration

Always the #1 goal.

The 6 basic rights:

1. Right patient

2. Right drug

3. Right dose

4. Right route

5. Right time

6. Right documentation

Additional rights:

• Right assessment (check relevant data, e.g., BP before antihypertensive)

• Right education (inform about purpose, side effects, etc.)

• Right evaluation (check effectiveness)

• Right to refuse (document and notify provider if refusal risks patient safety)

Medication orders must include: date, time, drug name, dose, route, frequency, duration, and prescriber’s signature