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Pharmacology
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Pharmacology Test 1

Generic vs. Brand-Name Medications

  • Same chemical composition and effects.
  • Generic = cheaper than brand-name.
  • One generic name only (official, universal).
  • Generic names start with lowercase. Brand name ⇒ Uppercase.
  • Brand/trade name = proprietary, can vary by manufacturer.
  • Abuse potential: No difference between generic and brand.

Prescription vs. Nonprescription

  • Prescription medications: Require a healthcare provider’s authorization.
  • Nonprescription/Over-the-counter (OTC): Do not require a prescription because the FDA designates them as safe for self-use without supervision.

Pharmaceutics (Study of drugs)

Focuses on:

  • How medication form affects dissolution.
  • How dissolution affects the absorption rate.
  • How absorption affects the onset of action.

Oral Medications

  • Forms: tablets, capsules, powders, liquids.
  • Absorption depends on form.
    • Inhaled powders → lungs.
    • Oral disintegrating tablets (ODT) → dissolve in the mouth. No need to chew.
      • image
  • Special formulations:
    • Immediate-release: dissolve quickly after swallowing.
    • Enteric-coated (EC): dissolve in the intestine (protects stomach or drug). Do not crushed or disolved
      • ‣
      Extended-release (ER, XL, SR, XR, SA): release over time.
      • Extended-release (ER): General term for prolonged release.
      • Extended length (XL): General term for prolonged release.
      • Sustained release (SR): General term for prolonged release.
      • Extended release (XR): General term for prolonged release.
      • Sustained action (SA): General term for prolonged release.

Tablet Rules

  • Scored tablets → may be split.
    • image
  • Never crush:
    • Capsules
    • Extended-release (ER, SR, XR, XL, SA)
    • Enteric-coated (EC)

Parenteral (Injectable) Medications

You can administer parenteral medications three main ways:

  • IV (Intravenous): Into a vein.
  • SUBQ (Subcutaneous): Into subcutaneous tissue.
  • IM (Intramuscular): Into muscle tissue.

Parenteral meds are usually:

  • Liquid form, ready for injection.
  • Dry form requiring reconstitution (adding liquid to dissolve).
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Example:

Powdered ceftriaxone (Rocephin) must be mixed with sterile water or lidocaine before injection.

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Parenteral Medication Absorption & Onset

Route
Absorption
Onset
Intravenous (IV)
Immediate and complete
Immediate
Intramuscular (IM)
Faster than SUBQ if water-soluble & circulation is good. Slower if poorly soluble or poor circulation.
~10–30 minutes
Subcutaneous (SUBQ)
Slower than IM. Rapid if water-soluble & good circulation; slow if poorly soluble or poor circulation.
Variable

✅ Key point to remember for exams:

IV → fastest → immediate. IM → second fastest (10–30 min).

SUBQ → slower, more variable.

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Explanation
  • Muscles have a richer blood supply than subcutaneous tissue, so drugs diffuse into circulation more quickly.
  • Subcutaneous tissue has fewer blood vessels, so absorption is slower.
  • Still, the actual speed depends on solubility of the medication and blood flow at the site (for example, a cold, poorly perfused muscle will absorb slower).

Topical or Transdermal Medications

  • Definition: Medications applied to the skin or mucous membranes (eyes, ears, nose, rectum, vagina, or lungs).
  • Action:
    • Deliver a constant amount of medication over an extended period.
    • Slower onset of action compared to oral or parenteral routes.
    • Longer duration of action.

Pharmacokinetics vs Pharmacodynamics

  • Pharmacokinetics is what the body does to the drug (absorption, distribution, metabolism, excretion).
  • Pharmacodynamics is what the drug does to the body (mechanism, effects, potency, efficacy).

Pharmacokinetics (PK) = What the body does to the drug

📌 Definition: The study of how the body absorbs, distributes, metabolizes, and excretes a drug.

✅ Think: PK = The journey of the drug inside the body.

image

🔹 4 Key Processes (ADME):

  1. Absorption – How the drug enters the bloodstream (oral, IV, IM, SUBQ, etc.). Movement of a medication from the site of administration into the bloodstream.
    2. ‣
    Expand
    • Factors that affect absorption:
      • Taking multiple drugs → interactions may delay or enhance absorption.
      • Weakly acidic drugs → absorb better in the stomach.
      • Weakly basic drugs → absorb better in the small intestine.

        • Bioavailability: The fraction (%) of a drug that actually reaches systemic circulation after absorption. How much is actually available?

    • First-Pass Effect: Oral drugs go through the liver first, where some of the drug is inactivated before reaching circulation. This does not apply to sublingual medication. Why?? Blood from the stomach and intestine goes to liver before reaching general circulation. The more the-First Pass effect, less Bioavailability

    image
  2. Distribution (Blood-stream) – How the drug is transported through the body (e.g., binding to proteins, reaching target tissues). Transport of the medication by the circulatory system to the site of action.
    3. ‣
    Expand
    • Blood Flow: Organs with higher blood flow (heart, liver, kidneys) get drugs faster.
    • Tissue Affinity: Drugs with high affinity for fat, bone, or muscle may accumulate and release slowly → slower distribution.
    • Protein Binding: Drugs attach to plasma proteins (like albumin); only the free drug is active.
    • Free Drugs: The unbound portion moves into tissues and produces the effect.
  3. Metabolism (Biotransformation) – How the liver (mostly) or other organs break down the drug. Conversion of the medication into a more or less potent or more soluble form (mainly in liver, also kidneys, intestines, etc.). Example: First-pass effect in oral meds.
    4. ‣
    Expand
    • Main site: Liver (also kidneys, lungs, intestinal mucosa).
    • First-pass metabolism reduces the amount of active drug if given orally.
  4. Excretion – How the drug leaves the body. Elimination of the medication or its metabolites (kidneys = urine, liver = bile, lungs = exhalation).

Pharmacodynamics (PD) = What the drug does to the body

📌 Definition: The study of the biological and physiological effects of the drug on the body and its mechanism of action.

🔹 Key Concepts:

  • Receptor binding (agonist vs antagonist).
  • Dose–response relationship (higher dose = stronger effect, up to a limit).
  • Therapeutic effect (intended action).
  • Adverse effects / side effects.
  • Potency & efficacy:
    • Potency: How much drug is needed for an effect.
    • Efficacy: How strong the maximum effect can be.

✅ Think: PD = The effect the drug has on the body.

  • Maximal Efficacy: The point at which increasing a drug’s dosage no longer increases the desired therapeutic response. Beyond this point, additional dosing only raises the risk of adverse or toxic effects without improving benefit.
  • Tachyphlaxis: Acute, rapid decrease in response to a drug.

🔹 Therapeutic Index (TI)

  • Definition: Ratio between a drug’s toxic dose and its therapeutic dose.
  • Formula:

    • TI = Toxic Dose (TD₅₀) ÷ Effective Dose (ED₅₀)

  • Narrow TI (e.g., digoxin, lithium) → requires close monitoring.
  • Wide TI (e.g., penicillin) → safer margin between effective and toxic doses.

✨ Quick Memory Trick:

  • Kinetics = move → What the body does to the drug (movement through ADME).
  • Dynamics = do → What the drug does to the body (effects, mechanisms).

⏱ Medication Timing

  • Half-life → time for drug level to ↓ by 50%.
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  • Onset → time to first therapeutic effect.
  • Peak → max effect.
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  • Duration → how long effect lasts.
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  • Peak & trough → blood samples; peak = max level, trough = lowest level.
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🔐 Mechanisms of Action

  • Agonist (trigger) → activates receptor.
  • Antagonist (blocker) → blocks receptor.
  • Selective → acts only on specific receptor.

    • Competitive vs Non-Competitive Antagonism

  • Competitive (👥 same seat): Competes for receptor; ↑ agonist can overcome; effect curve shifts right.
  • Non-competitive (🔒 broken seat): Irreversible/different site; ↑ agonist cannot overcome; max effect reduced.

💊 Drug Interaction Types (Short + Explained)

  • Additive Effect

    • ➤ 1 + 1 = 2

    Two drugs work together; their effects simply add up.

    ✅ Example: Tylenol + Ibuprofen for pain relief.

  • Synergistic Effect / Potentiation

    • ➤ 1 + 1 = 3 (or more)

    Two drugs boost each other, creating a stronger effect than either alone.

    ✅ Example: Alcohol + Sedatives = dangerous sedation.

⚠️ Adverse Drug Reactions (ADR)

  • ADR = unintended bad effect at therapeutic dose.
  • Most severe → allergic reaction.
  • Anaphylaxis: massive histamine release →
    • Hypotension, tachycardia.
    • Wheezing, difficulty breathing.
    • Airway swelling (tongue, face, throat).
    • Tx = airway, oxygen, epinephrine, diphenhydramine.
      • image

      NOTE: Bradichardia is not a sign of anaphylaxis

📉 Medication Issues

  • Tolerance → ↓ response over time (ex: opioids).
  • Withdrawal → abrupt stop → symptoms.
  • Toxicity → excessive level (overdose or impaired excretion).
  • Cumulative effect → body can’t clear before next dose.
  • Sensitivity → exaggerated response.

⚖️ Precautions & Contraindications

  • Use extra caution in chronic/multiple conditions.
  • Boxed warning → strongest FDA warning.
  • Contraindication → don’t give (unless rare emergency).
  • Dosage adjustments often needed in children (based on age, weight, surface area).

🍊 Food & Drug Interactions

Food
Medication
Effect
Grapefruit juice
Sertraline, Fexofenadine, Nifedipine
↑ toxicity (slowed metabolism)
Tyramine foods (wine, meats)
MAOIs (Isocarboxazid, Tranylcypromine)
Hypertensive crisis
Milk
Tetracycline
↓ therapeutic effect
Avocados
Warfarin
↓ therapeutic effect
High-protein meals
Levodopa
Sudden ↓ effect

➕➖ Drug Interactions

  • Additive (sum of effects):
    • Ex: acetaminophen + codeine → stronger pain relief.
    • ✅ Clients need lower doses.
    • ✅ Both drugs have similar actions.
  • Synergistic (greater than sum).
  • Antagonistic (one reduces effect of other).

👩‍🍼 Postpartum Medication & Baby

  • Factors to consider in breastfeeding:
    • Baby’s weight (lighter → higher risk).
    • Amount of breast milk consumed.
    • We can not give or add medication to a baby bottle of milk cause if the baby doesn’t consume the hole bottle, then we won’t be able to know how much of the drug was actually consumed.
    • Medication properties (fat solubility, transfer).
    • Balance benefits vs risks.
    • ❌ Route of administration → not protective (any systemic med can pass).

🧠 Learning Factors (Patient Teaching)

  • Affect learning:
    • Impaired cognition/developmental level.
    • Language barrier.
    • Discomfort/pain.
    • Lack of readiness (denial, distress).
  • Enhance learning:
    • Repetition, practice, reinforcement.

🧠 Controlled Substance Schedules Overview\

Schedule
Abuse Potential
Examples
Notes / Restrictions
I
🔴 No accepted medical use in the U.S. 🔺 High abuse potential
Hallucinogens, heroin, LSD, methaqualone
🚫 Not available for medical use Only for research/chemical analysis
II
🔺 High abuse potential ⚠️ Severe psychological/physical dependence risk
Morphine, codeine, oxycodone, methadone, amphetamines, fentanyl, hydromorphone
✅ Prescription required ⛔ No refills allowed Can be faxed only for hospice/LTC
III
⚠️ Less abuse potential than I/II Moderate to low physical dependence
Codeine combo products (e.g., Tylenol #3), buprenorphine, ketamine
✅ Written or verbal Rx allowed 🔁 Refill up to 5 times in 6 months
IV
⚠️ Low potential for abuse Limited physical/psychological dependence
Benzodiazepines (diazepam, lorazepam), phenobarbital, tramadol
✅ Same rules as Schedule III
V
✅ Lowest abuse potential Limited amounts of narcotics
Cough syrups with codeine, pregabalin (Lyrica), anti-diarrheals
🛒 Some sold without a prescription (depends on state laws)

📌 Study Tip:

Use this mnemonic to remember abuse potential:

"I Have Absolutely No Medical Use!"

II = Intense

III = In Between

IV = Very light

V = Very minimal

⚖ Misfeasance, Malfeasance, Nonfeasance

🔹 1. Misfeasance ⇒ Simple Mistake.

• Doing something legal, but doing it wrongly.

• ❌ Right act, wrong way.

• Example: Giving the correct medication, but by the wrong route. Making a simple mistake in the procedure.

🔹 2. Malfeasance ⇒ Maleficent

image

• Doing something completely wrong or illegal.

• ❌ Wrong act, on purpose or reckless.

• Example: Stealing meds from a patient, or hitting a patient.

🔹 3. Nonfeasance ⇒ No action.

• Failing to act when you should have.

• ❌ No action at all.

• Example: Not calling the doctor when a patient’s condition worsens.

🧠 Memory Trick

Think of the first part of the word:

• Mis- = mistake (did it, but wrong).

• Mal- = malicious/bad (bad or illegal act).

• Non- = none (did nothing at all).

🧪 Drug Development Process (Overview)

🔷 1. Basic Research (Up to 6 years)

  • Activities:
    • Genetics
    • Pathophysiology
    • Mechanism of disease
  • Goal: Understand the biology of the disease and identify drug targets

🧬 2. Drug Target Identification & Validation

  • Activities:
    • Finding a molecular target (e.g., protein, enzyme)
    • Validating it through experiments

🧫 3. Preclinical Assessment

  • Includes:
    • Pharmacology & Toxicology (Animal studies)
    • In vitro & in vivo testing
    • ADME (Absorption, Distribution, Metabolism, Excretion)

🔄 4. IND Application (Investigational New Drug)

  • Submitted to the FDA to get permission to begin human testing

👨‍⚕️ Clinical Development Phases (Up to 9 years)

🔹 Phase I: Safety

  • Participants: 20–100 healthy volunteers
  • Focus:
    • Safety
    • Tolerability
    • Pharmacokinetics (PK)
    • Pharmacodynamics (PD)

🔸 Phase II: Efficacy & Dose Optimization

  • Participants: 100–300 patients
  • Goal:
    • Find effective dose
    • Begin testing in people with the condition
    • Monitor side effects

🔻 Phase III: Large-Scale Efficacy & Monitoring

  • Participants: 1,000–5,000 patients
  • Goal:
    • Confirm effectiveness
    • Monitor adverse reactions
    • Compare to current treatments
    • Pivotal for FDA approval

📦 5. Post-Marketing Surveillance (Phase IV)

  • Continues after FDA approval
  • Focus on long-term safety, rare side effects, and effectiveness in real-world use

💵 Total Time & Cost

  • ⏱️ 10–15 years total
  • 💰 Approximate cost: $2.6 billion

🍼 FDA Pregnancy Risk Categories (Old System)

Category
Meaning
Emoji Summary
Notes
A
✅ No risk to fetus in controlled human studies
😊
Safest option. Rare in real-world use.
B
✅ No risk in animal studies but no well-controlled studies in pregnant women
🙂
Likely safe, but human data limited
C
⚠️ Animal studies show risk to fetus; no human data
😐
Use only if benefits outweigh risks
D
❗ Risk to fetus proven in humans
😟
May be used if benefits justify the risk (e.g., life-threatening condition)
X
🚫 Risk proven; risk > benefit
😢
Never use in pregnancy. Contraindicated.

💡 Easy Mnemonic:

A = "Alright"

B = "Be careful"

C = "Caution"

D = "Danger"

X = "X = NO"

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⚠️ Note:

The FDA replaced this system in 2015 with the Pregnancy and Lactation Labeling Rule (PLLR) — a more detailed narrative instead of letter grades. However, many NCLEX-style questions and textbooks still refer to these letters, so it’s good to memorize them.

💊Rights of Medication Administration

  1. 🧍 Right Patient

    2. Always verify patient identity with at least two identifiers.

  2. 💊 Right Drug

    3. Confirm medication name matches the order.

  3. 📏 Right Dose

    4. Ensure dosage is accurate for patient age, weight, and condition.

  4. 🩸 Right Route

    5. Verify correct route (oral, IV, IM, SQ, etc.).

  5. 🕒 Right Time

    6. Administer at the correct time and frequency.

  6. 🙅 Right to Refuse (Patient & Nurse)

    7. Respect patient autonomy and nurse’s ethical safety concerns.

  7. 📚 Right Knowledge & Understanding

    8. Ensure patient education and your own full comprehension of the drug.

  8. ❓ Right Questions or Challenges

    9. Speak up if something seems unclear, unsafe, or incorrect.

  9. 🗣️ Right Advice

    10. Provide clear instructions about medication use and precautions.

  10. 👀 Right Response

    11. Monitor and evaluate the patient’s reaction to the medication.

🔹 Nonselective vs Nonspecific

  • Epinephrine = Nonselective (acts on alpha & beta receptors)
  • Cholinergic receptors = Selective (non-specific) (specific to acetylcholine)

🔍 Explanation

  • Nonselective drugs like epinephrine activate multiple types of receptors (α1, β1, β2), leading to broad effects.
  • Cholinergic receptors (muscarinic & nicotinic) are more targeted, so drugs that affect them tend to be selective in action.

QUIZES

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Idiosyncrasy

An unusual and unpredictable reaction to a drug, not related to dose or allergies. An unusual or unexpected drug reaction by an individual is known as

Side effects are expected.

🧬 Often genetic.

❌ Not a typical side effect.

Example:

  • Primaquine causing hemolysis in G6PD-deficient patients.
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⚕️ Posology (Quick Definition)

Posology is the study of drug dosages — how much of a drug should be given to a patient.

🔹 In Simple Terms:

"Posology = Dose study"

It deals with:

  • 📏 Amount of drug
  • ⏱️ Frequency (how often)
  • 📆 Duration (how long)

📍Example:

  • Paracetamol 500 mg every 6 hours for 3 days

    • → That’s posology!

In order for drugs to cross the blood-brain barrier, they must be LIPID SOUBLE Drug absortion is faster for Lipidic drugs. Membranes are lipidics.

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💊 Drug Induction Explained (Simple)

🔥 What is Drug Induction?

When a drug induces (stimulates) liver enzymes, it makes the liver work faster to break down medications. This means:

  • Other drugs are metabolized faster
  • Their effects wear off quicker
  • The body eliminates them faster

⚠️ Why It Matters:

Drug induction can:

  • Decrease the effectiveness of other drugs
  • Lead to treatment failure
  • Require dose adjustments

🔁 Opposite of Induction = Inhibition

Where a drug slows down metabolism and causes drug accumulation.

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🧠 What is the Placebo Effect?

The placebo effect refers to positive therapeutic outcomes that occur simply because the patient believes the treatment will work, even if the treatment has no active ingredient (like a sugar pill or saline injection).

💡 Why It's a Factor of Individual Variation:

  • It varies from person to person.
  • It's influenced by the patient's:
    • Beliefs
    • Expectations
    • Trust in the provider
    • Previous experiences with medications
  • It can enhance the perceived effectiveness of a real or fake treatment.

🔍 In Pharmacology:

  • Even active drugs can be more effective in some patients because of positive expectations.
  • The placebo effect can alter drug response by:
    • Boosting adherence
    • Enhancing symptom relief (especially pain, depression, anxiety)
    • Engaging mind–body interactions

⚠️ Clinical Note:

There’s also a nocebo effect — when negative expectations lead to worse outcomes or side effects, even with inactive substances.

✅ Summary

Factor
Definition
Placebo Effect
A psychological response where belief in a treatment leads to real symptom relief, even if the treatment has no active ingredients
Dependent On:
Patient’s attitude, expectations, and beliefs
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Instillations

Instillations refer to the process of introducing liquid medication or solutions into a body cavity, such as the bladder, through a catheter. This treatment is commonly used for bladder instillation, a therapy for interstitial cystitis (painful bladder syndrome) and recurrent urinary tract infections (UTIs)