Medication Administration & Dosage Calculation - Cheat Sheet
Your last-minute exam companion covering every formula, right, route, and critical safety principle for NLE success. Review in 30 minutes before the exam.
Core Dosage Calculation Formulas
Formulas
Dose to Give = (Desired ÷ Have) × Quantity = D/H × Q
Meaning
Desired = ordered dose; Have = strength on hand; Quantity = volume/amount of one dose unit
Watch out
Do NOT skip unit conversion—if desired is in mg and have is in g, convert first or you will give 1000× the dose
When to use
Every time you calculate a medication dose from stock strength (tablets, capsules, liquids)
Weight-Based Dose = mg/kg × patient weight in kg
Meaning
mg/kg = prescribed dose per kilogram; always convert pounds to kg first (1 kg = 2.2 lb)
Watch out
Forgetting to convert lb to kg is the #1 error; you will underdose or overdose significantly—always divide lb by 2.2
When to use
Pediatrics, chemotherapy, antibiotic dosing, and any order that specifies mg/kg
IV Flow Rate (mL/hr) = Total Volume (mL) ÷ Total Time (hr)
Meaning
Used for electronic infusion pumps; gives steady rate in milliliters per hour
Watch out
Make sure time is in HOURS, not minutes; if given 480 minutes, divide by 60 first to get 8 hours
When to use
Setting up any IV on an electronic pump or calculating pump settings
IV Drip Rate (gtt/min) = [Total Volume (mL) × Drop Factor (gtt/mL)] ÷ Total Time (min)
Meaning
gtt/min = drops per minute for gravity infusion; drop factor varies by IV set (10, 15, 20, or 60 gtt/mL)
Watch out
Confusing drop factor units—always check your IV set package; microdrip = 60 gtt/mL = 1 mL/drop, NOT 1 gtt/mL
When to use
Gravity infusions without a pump; must round to nearest whole number (cannot deliver partial drop)
Pediatric Clark's Rule (if weight not given) = Child Wt (lb) ÷ 150 lb × Adult Dose
Meaning
Estimates child dose when only adult dose is available and weight is missing
Watch out
This is an estimate only—always verify with safe dose range and never substitute for actual weight-based calculation
When to use
Rare in modern practice but still tested on NLE; always prefer weight-based dosing
IV Concentration = Drug Amount (mg) ÷ Total Volume (mL)
Meaning
Tells you how many mg are in each mL of solution (e.g., 100 mg/mL)
Watch out
Always know the concentration on hand before drawing up; insulin vials vary (100 units/mL or 50 units/mL)
When to use
When calculating how many mL to draw up of a concentrated drug (e.g., insulin, heparin, concentrated KCl)
Common values
Value
60 gtt/mL
Symbol
gtt/mL
Quantity
Microdrip drop factor
Value
10, 15, or 20 gtt/mL
Symbol
gtt/mL
Quantity
Macrodrip drop factor (common)
Value
5 mL
Symbol
mL
Quantity
Standard teaspoon
Value
15 mL
Symbol
mL
Quantity
Standard tablespoon
Value
30 mL (approx)
Symbol
mL
Quantity
Standard ounce
Value
1,000 mg
Symbol
mg
Quantity
1 gram
Value
1,000 mcg (µg)
Symbol
mcg
Quantity
1 milligram
Value
2.2 pounds
Symbol
lb
Quantity
1 kilogram
Value
1,000 mL
Symbol
mL
Quantity
1 liter
Important facts
- Conversions: 1 g = 1,000 mg; 1 mg = 1,000 mcg (µg); 1 kg = 2.2 lb; 1 L = 1,000 mL; 1 tsp = 5 mL; 1 tbsp = 15 mL; 1 oz ≈ 30 mL
- Always convert to the SAME unit before calculating; mixing units = wrong answer
- Use LEADING ZERO for decimals <1 (write 0.5 mg, NOT .5 mg); NEVER use trailing zero (NOT 5.0 mg—safety risk in prescriptions)
- The formula D/H × Q works for ANY unit as long as D and H are in the SAME unit
- Microdrip = 60 gtt/mL; 1 gtt = 1 mL; often used for pediatrics, medications needing precision, or older patients with fragile veins
- Macrodrip = 10, 15, or 20 gtt/mL; used for large volumes needing faster infusion in stable adults
- IV pumps are NOT 100% accurate—always check line and site visually every hour; gravity sets depend on gravity and may slow over time
- Always ROUND gtt/min to nearest whole number (you cannot give 31.5 drops)
- For weight-based dosing in pediatrics, verify the calculated dose is within the SAFE DOSE RANGE in drug references before giving
Key definitions
Desired Dose
Example
Order reads 'metformin 500 mg PO BID' — desired dose = 500 mg
The amount of medication ordered by the physician for this patient at this time.
Dose on Hand (Stock Strength)
Example
Metformin tablet labeled '250 mg per tablet' — have = 250 mg
The concentration or strength of the medication available in the medication storage (bottle, vial, or unit dose).
Bioavailability
Example
IV has 100% bioavailability (all drug enters bloodstream); oral may be 50–80% (some absorbed in GI tract)
Percentage of an administered dose that reaches systemic circulation and is available to produce a therapeutic effect.
Half-Life (t½)
Example
Warfarin t½ ≈ 40 hours; dosing once daily is sufficient; tobramycin t½ ≈ 2 hours; needs multiple daily doses
Time required for plasma drug concentration to fall by half; determines dosing intervals.
Therapeutic Range
Example
Digoxin therapeutic range: 0.5–2.0 ng/mL; below = ineffective, above = toxicity risk
The plasma concentration range at which a drug is safe and effective without toxicity.
Onset, Peak, and Duration
Example
IV morphine: onset 5 min, peak 15–20 min, duration 3–6 hrs; assess pain before and after peak time
Onset = time from administration to first effect; peak = maximum drug concentration/effect; duration = total time drug is active.
Diagrams to know
- The D/H × Q formula and how each component changes the answer
- IV flow rate calculation pathway (is it a pump? gravity? what is the drop factor?)
- Pound-to-kilogram conversion (always ÷ 2.2, never × 2.2)
Routes of Administration & Injection Angles
Common values
Value
10–15 degrees
Symbol
°
Quantity
Intradermal angle
Value
45–90 degrees
Symbol
°
Quantity
Subcutaneous angle
Value
90 degrees (perpendicular)
Symbol
°
Quantity
Intramuscular angle
Value
0.1 mL
Symbol
mL
Quantity
Intradermal max volume
Value
1 mL
Symbol
mL
Quantity
Subcutaneous max volume
Value
3 mL (deltoid: ≤1 mL)
Symbol
mL
Quantity
Intramuscular max volume (adult)
Important facts
- ORAL (PO): safest, most convenient; slower onset; do NOT crush enteric-coated or sustained-release tablets
- SUBLINGUAL (SL): under tongue; bypasses first-pass metabolism (absorbed directly into bloodstream); e.g., nitroglycerin
- BUCCAL: against cheek; slower absorption than SL; do not chew or swallow
- TOPICAL/TRANSDERMAL: skin application; rotate patch sites; remove old patch before applying new; slow onset, long duration
- INHALATION: via lungs; rapid onset; used for bronchodilators and anesthetics; teach patient proper MDI/nebulizer technique
- INSTILLATION: eye, ear, nose drops; do NOT share applicators to prevent cross-infection
- RECTAL: suppository; slower than PO; useful if patient NPO or vomiting
- INTRAMUSCULAR SITES (in order of safety): 1) Ventrogluteal (safest—away from major nerves/vessels; even for infants), 2) Vastus lateralis (preferred for infants <7 months), 3) Deltoid, 4) Dorsogluteal (AVOID—risk of sciatic nerve damage)
- Do NOT aspirate after SC heparin or enoxaparin injection—causes bruising/hematoma; gentle massage also not recommended
- SC insulin injection: rotate sites in a pattern (e.g., abdomen, then arms, then legs, then back to abdomen next week); avoid ~5 cm radius around umbilicus
Key definitions
Intradermal (ID)
Example
Mantoux (TB) test, allergy testing—read result at 48–72 hours
Injection into the dermis for allergy testing or TB screening; 10–15° angle; forms a bleb/wheal; volume ≤0.1 mL.
Subcutaneous (SC/SQ)
Example
Insulin, heparin, enoxaparin, vaccines; rotate sites to avoid lipodystrophy
Injection into fatty tissue under skin; 45–90° angle; volume ≤1 mL (usually 0.5 mL); absorbs slowly.
Intramuscular (IM)
Example
Vaccines, antibiotics, hormones; use Z-track for irritating drugs
Injection into muscle; 90° angle; adult volume up to 3 mL (deltoid ≤1 mL); faster absorption than SC.
Intravenous (IV)
Example
Fluids, antibiotics, chemotherapy, emergency medications
Injection directly into a vein; immediate onset, 100% bioavailability; highest risk; requires strict asepsis and monitoring.
Z-Track Technique
Example
Iron dextran, magnesium sulfate, certain antibiotics—prevents tissue staining and irritation
For IM injections: displace skin 1–1.5 inches laterally, inject, then release skin to seal puncture and prevent drug leakage into SC tissue.
Diagrams to know
- Injection angles: ID 10–15°, SC 45–90°, IM 90°
- IM injection sites: ventrogluteal, vastus lateralis, deltoid, dorsogluteal (with risk)
- Z-track injection sequence: displace → insert → inject → release
The Ten Rights of Medication Administration
Important facts
- THREE CHECKS of the label: (1) when removing from storage, (2) when preparing/pouring, (3) at bedside before administering
- If patient questions a medication, STOP and re-verify the order before giving—patient insight is valuable
- NEVER leave oral medications at bedside; stay with patient until swallowed to confirm administration
- Use PATIENT'S NAME when speaking to them, not room number, to ensure you have the right person
- Check for ALLERGIES before EVERY dose; ask about environmental allergies too (e.g., penicillin if allergic to shellfish—cross-reaction possible)
- HIGH-ALERT drugs (insulin, heparin, anticoagulants, opioids, KCl, chemotherapy, neuromuscular blockers) require independent double-checks by two nurses
- If you make a medication error: (1) assess patient immediately, (2) notify prescriber and unit manager, (3) complete incident report, (4) document honestly in chart; never hide or document falsely
- Medication reconciliation at hospital admission and discharge is a patient safety requirement under PRC and RA 9173
- For patients in ICU or on multiple medications, verify orders in the medical record match the MAR before administering
- Safe abbreviations only: use 'units' (not U), 'mcg' (not µ), leading zeros (0.5 mg), NO trailing zeros (not 5.0 mg)
Key definitions
Right Patient
Example
Ask patient to state name and compare to wristband; check hospital ID and birthdate against MAR
Verify identity using TWO identifiers (name + hospital ID or birthdate); NEVER use room number alone.
Right Drug
Example
Order says 'amoxicillin' but label reads 'ampicillin'—STOP, do NOT give; notify prescriber
Verify ordered drug name against the label; check for look-alike/sound-alike names (e.g., cefazolin vs cephalexin).
Right Dose
Example
Order: 500 mg; on hand 250 mg tablets. Calculate: 500/250 × 1 = 2 tablets. Do not give 1 tablet.
Calculate dose and verify it matches the order; double-check high-alert drugs (insulin, heparin, KCl, opioids).
Right Route
Example
If order is 'metformin 500 mg PO' but patient is NPO, clarify with prescriber before giving IV
Confirm the route ordered (PO, IV, IM, SC, etc.) matches the drug form available and patient's ability to take it.
Right Time/Frequency
Example
Order 'ampicillin 500 mg q6h' = give at 0600, 1200, 1800, 2400; NOT all at once
Administer at the correct time and interval; respect q6h (every 6 hours), BID (twice daily), AC (before meals), etc.
Right Documentation
Example
In MAR: 'Acetaminophen 500 mg PO at 1000; patient tolerated well; pain decreased to 3/10 at 1030'
Chart AFTER giving the medication, NEVER before; record drug name, dose, route, time, site (if injection), and patient response.
Right Reason/Indication
Example
Patient with no fever does not need acetaminophen; patient with normal BP may not need antihypertensive—question the order
Verify the therapeutic purpose—why is this patient getting this drug? (e.g., for fever, hypertension, infection).
Right Assessment
Example
Before giving metoprolol, check heart rate; if HR <60, hold and notify. Before morphine, check respiratory rate; if RR <12, hold.
Check relevant vital signs and parameters BEFORE administering (e.g., apical pulse before digoxin, BP before ACE inhibitor, RR before opioid).
Right Response/Evaluation
Example
After IV morphine (peak 15–20 min), reassess pain and respiratory status; document patient response
Monitor the patient AFTER administration to assess therapeutic effect and adverse effects; reassess at peak time.
Right to Refuse
Example
Patient refuses antihypertensive due to side effects—do not give; chart reason; inform MD for alternative
Patient may decline any medication; STOP, do NOT force; document reason, notify prescriber, and continue monitoring.
Diagrams to know
- The Ten Rights checklist pathway
- Three checks of the label timeline
- Two-identifier verification process
IV Therapy: Fluids, Tonicity, and Complications
Common values
Value
280–310 mOsm/L
Symbol
mOsm/L
Quantity
Normal plasma osmolality
Value
72–96 hours
Symbol
hours
Quantity
Peripheral IV catheter change interval
Value
60 gtt/mL
Symbol
gtt/mL
Quantity
Microdrip used for IV medications
Important facts
- ISOTONIC fluids (0.9% NaCl, LR) are FIRST-LINE for fluid replacement in most dehydrated patients; expand extracellular fluid
- D5W = 5% dextrose in water; isotonic in the bag but becomes HYPOTONIC after dextrose is metabolized—useful as maintenance fluid and for glucose delivery
- HYPOTONIC solutions shift fluid into cells; used for hypernatremia and cellular dehydration; CONTRAINDICATED in increased ICP (brain swells further)
- HYPERTONIC solutions used for severe hypervolemia, cerebral edema, and hypernatremia; give SLOWLY via pump or central line; monitor for vein irritation
- Assess IV site EVERY HOUR minimum; check color, warmth, swelling, pain, flow rate, presence of blood in catheter
- Change peripheral IV catheter per facility policy (typically every 72–96 hours); central lines per protocol (usually 10–14 days)
- Maintain strict asepsis during dressing changes and IV site care to prevent CLABSI (catheter-related bloodstream infection)
- Always verify IV fluid compatibility before mixing or co-infusing medications; some combos precipitate and block the line
- KCl NEVER given as IV push—FATAL; must be diluted and infused slowly (20 mEq/L in saline over 1–4 hours depending on serum K level)
- For patients on diuretics or with renal disease, monitor for electrolyte abnormalities; check Na, K, Cl, BUN, Cr regularly
- If infiltration or extravasation suspected: STOP infusion immediately, remove catheter, assess limb, notify MD, may require topical treatments or compartment assessment
Key definitions
Isotonic Solution
Example
0.9% NaCl (normal saline), lactated Ringer's (LR), D5W (isotonic in bag, becomes hypotonic after dextrose metabolized)
Same osmolality as plasma (~280 mOsm/L); does NOT shift fluid between compartments; expands ECF volume.
Hypotonic Solution
Example
0.45% NaCl (half-normal saline), 0.33% NaCl; risk of cerebral edema and hyponatremia; NEVER use in increased ICP
<280 mOsm/L; shifts fluid INTO cells (causes cells to swell); used for cellular dehydration.
Hypertonic Solution
Example
3% NaCl, 5–10% dextrose solutions; given slowly via central line when possible; monitor for vein irritation and hyperglycemia
>280 mOsm/L; pulls fluid OUT of cells into vascular space; used for fluid overload and cerebral edema.
Infiltration
Example
Peripheral line in arm swells; skin around site pale and cool; fluid flows slowly. Action: stop, remove catheter, elevate limb, apply warm/cool compress per solution
IV fluid leaks into surrounding tissue instead of entering the vein; causes swelling, coolness, pallor, no blood return.
Phlebitis
Example
Peripheral IV site becomes red and warm; patient reports pain along vein. Action: discontinue IV, restart in another site, warm compress, monitor
Vein inflammation from mechanical irritation or chemical injury; presents with redness, warmth, pain, palpable cord.
Extravasation
Example
Chemotherapy (doxorubicin), potassium, calcium, some antibiotics if infiltrated can cause permanent tissue damage—stop infusion immediately, notify MD
Leakage of a vesicant (tissue-damaging) drug into surrounding tissue; medical emergency causing tissue necrosis.
Fluid Overload (Circulatory Overload)
Example
Patient receiving 1 L/hr × 6 hours; now short of breath, crackles bilaterally, BP 160/100. Action: slow to KVO rate, raise HOB, notify MD, give O2, monitor I&O
Excessive IV fluid infusion causing pulmonary edema, hypertension, and cardiovascular stress; signs: dyspnea, crackles, distended neck veins.
Air Embolism
Example
IV tubing disconnects and air enters during infusion; patient suddenly dyspneic, chest pain, hypotension—emergency
Air bubble enters vein and travels to lungs/heart; potentially fatal; prevention: prime all tubing, secure connections, regulate pressure.
Speed Shock
Example
IV antibiotic infused too fast (over 5 min instead of 30 min); patient develops fever, chills, shock—always check infusion times
Rapid IV drug infusion causing systemic toxicity; signs: flushed face, headache, tightness in chest, tachycardia, hypotension.
Diagrams to know
- IV fluid tonicity spectrum: hypotonic vs isotonic vs hypertonic and where they work
- IV complication assessment tree: is it infiltration, phlebitis, extravasation, or fluid overload?
- IV site inspection checklist
High-Alert Medications & Antidotes
Common values
Value
Units only (U100 = 100 units/mL)
Symbol
units
Quantity
Insulin syringe marking
Value
3.5–5.0 mEq/L
Symbol
mEq/L
Quantity
Normal serum potassium
Value
25–35 seconds
Symbol
sec
Quantity
Normal aPTT (baseline)
Value
1.5–2.5× control
Symbol
fold
Quantity
Therapeutic aPTT on heparin
Value
0.8–1.1
Symbol
ratio
Quantity
Normal INR
Value
2–3 (most indications)
Symbol
ratio
Quantity
Therapeutic INR on warfarin
Value
70–100 mg/dL
Symbol
mg/dL
Quantity
Normal serum glucose (fasting)
Value
10 mEq/hr
Symbol
mEq/hr
Quantity
Max IV KCl infusion rate
Important facts
- INSULIN: Always use INSULIN SYRINGES (do NOT use TB or regular syringes); units ≠ mg; when mixing two types: CLEAR BEFORE CLOUDY (regular/short-acting, then NPH); rotate injection sites daily
- HEPARIN: Monitor aPTT (active partial thromboplastin time); therapeutic range 1.5–2.5× control; check aPTT 4–6 hr after initiation/dose change; half-life ~90 min IV, ~2 hrs SC
- ENOXAPARIN: SC only; do NOT give IV; weight-based dosing (prophylaxis vs treatment); do NOT aspirate—inject 45–90° angle into abdomen away from umbilicus; no massage
- WARFARIN: onset 3–5 days; monitor PT/INR; interaction with many drugs (NSAIDs, antibiotics, phenytoin); food with vitamin K (spinach, broccoli) decreases effect; patient education critical
- OPIOIDS: Assess pain level (0–10 scale) and respiratory rate BEFORE giving; hold if RR <12 or patient sedated; peak times: IV 15–20 min, IM 30–60 min, PO 1–2 hrs; watch for addiction risk
- POTASSIUM: Normal serum K = 3.5–5.0 mEq/L; IV KCl ALWAYS diluted and ALWAYS via pump; max infusion rate 10 mEq/hr; watch for peaked T waves (hyperkalemia) on ECG; risk of cardiac arrhythmia if too fast
- CONCENTRATED ELECTROLYTES (KCl >20 mEq/L): restricted item in medication storage; double-check before each draw; verify on pharmacy label
- CHEMOTHERAPY: calculated by BSA (body surface area in m²); high risk of error; second RN verification required; monitor for extravasation; hold if counts too low
- NEUROMUSCULAR BLOCKERS (succinylcholine, rocuronium): paralytic agents used during anesthesia; RN monitors paralysis depth; antidote for non-depolarizing = neostigmine + glycopyrrolate
- Always check for DRUG INTERACTIONS before giving high-alert drugs; verify renal/hepatic function is adequate for elimination (especially in older adults, pediatrics, renal disease)
Key definitions
High-Alert Drug
Example
Insulin, heparin, anticoagulants, opioids, concentrated KCl, chemotherapy, neuromuscular blockers
Medication with high risk of significant harm if given in error; requires independent double-check by two nurses before administration.
Insulin
Example
When mixing NPH and regular: 'clear before cloudy' (draw regular/short-acting first, then NPH); rotate SC sites
Hormone for glucose control; ALWAYS use INSULIN SYRINGES (U100 = 100 units/mL); monitor blood glucose.
Heparin & Enoxaparin
Example
Monitor aPTT for unfractionated heparin (goal 1.5–2.5× control); enoxaparin dosed by weight; antidote = protamine sulfate
Anticoagulants; heparin IV, SC; enoxaparin SC only; monitor for bleeding; do NOT aspirate or massage SC injection site.
Warfarin
Example
Vitamin K is the antidote; used for atrial fibrillation, mechanical heart valves, DVT/PE prophylaxis
Oral anticoagulant; takes 3–5 days for effect; monitor PT/INR (goal usually 2–3 for most indications).
Opioids
Example
Morphine 5–10 mg IV/IM; onset varies by route (IV 5 min, IM 15–30 min); peak 15–20 min IV; monitor pain and respiratory depression
Potent analgesics; assess respiratory rate BEFORE giving; hold if RR <12; naloxone is the antidote.
Potassium Chloride (KCl)
Example
Dilute 20 mEq KCl in 100–250 mL NS; infuse at ≤10 mEq/hr; never faster; monitor for infiltration (tissue damage)
Electrolyte replacement; NEVER given as IV push (causes fatal cardiac arrhythmias); must be diluted in IV fluid and infused slowly via pump.
Protamine Sulfate
Example
Dose: 1 mg per 100 units of heparin; given IV over 10 min; monitor aPTT to confirm reversal
Antidote for unfractionated heparin; reverses anticoagulant effect; give IV slowly to avoid hypotension.
Vitamin K
Example
Used for warfarin overdose with bleeding; dose 2.5–10 mg PO or IV; monitor PT/INR for reversal
Antidote for warfarin; restores vitamin K-dependent clotting factors; onset 12–24 hours.
Naloxone
Example
Patient with RR 8 after morphine: naloxone 0.4–0.8 mg IV; patient wakes and respiratory rate increases; assess for pain re-emergence
Antidote for opioid overdose; reverses respiratory depression; IV/IM/IN; onset 2–3 min IV; short duration, may need repeat doses.
N-Acetylcysteine
Example
Used within 24 hours of OD; loading dose IV, then tapering doses over 16 hours; monitor liver function
Antidote for acetaminophen overdose; protects liver by replenishing glutathione; given IV or PO.
Diagrams to know
- High-alert drug list and their antidotes
- Insulin injection site rotation pattern
- Heparin and warfarin monitoring parameters
Special Populations: Pediatrics & Older Adults
Formulas
Pediatric Clark's Rule = (Child Weight in lbs ÷ 150) × Adult Dose
Meaning
Estimates child dose when weight not given; older formula, less commonly used now
Watch out
This is a crude estimate—verify result against safe pediatric dose range in drug reference; never administer without verification
When to use
Rare; ALWAYS prefer weight-based dosing (mg/kg) when available; use Clark's Rule only if weight truly unavailable
Pediatric Dose = mg/kg ordered × child weight in kg
Meaning
Standard weight-based dosing for children; ensures safe, proportional dosing
Watch out
Forgetting to convert lb to kg is the #1 error in pediatric dosing; always divide lb by 2.2 first; double-check calculation with another nurse
When to use
ALL pediatric dosing—this is the gold standard; always check dose is within safe range BEFORE administering
Common values
Value
6–8 kg
Symbol
kg
Quantity
Typical pediatric weight (6 months)
Value
10–12 kg
Symbol
kg
Quantity
Typical pediatric weight (1 year)
Value
15–20 kg
Symbol
kg
Quantity
Typical pediatric weight (5 years)
Value
≥65 years
Symbol
years
Quantity
Older adult age threshold
Important facts
- PEDIATRIC DOSING: Always weight-based (mg/kg); volume is SMALL (often mL, not tablets); use oral syringes (not household spoons) for liquids; verify safe dose range in pediatric drug reference BEFORE giving
- PEDIATRIC CALCULATIONS: Convert lb to kg first (÷ 2.2); double-check D/H × Q calculation; round mL to nearest 0.1 mL; use appropriate measuring device
- Ventrogluteal IM site is safe even for INFANTS; vastus lateralis preferred for babies <7 months; deltoid used only in older children (arm muscle smaller)
- Pediatric drug orders: if calculated dose seems very small or very large, VERIFY immediately—medication error in pediatrics can be fatal
- OLDER ADULT DOSING: 'Start low, go slow'—lower initial dose, slower titration; assess renal function (eGFR, Cr, BUN) before dosing renally eliminated drugs
- Older adults on diuretics: monitor electrolytes (K, Na), renal function (Cr, BUN), BP, weight for fluid loss; teach signs of dehydration and orthostatic hypotension
- Polypharmacy assessment: review ALL medications (Rx, OTC, supplements) at each visit; check for duplicates, interactions, and appropriateness for age
- Common drug interactions in older adults: NSAIDs + ACE inhibitor + diuretic (hyperkalemia, AKI); warfarin + NSAIDs (bleeding risk); multiple CNS depressants (falls, confusion)
- Older adults at HIGH RISK for falls on medications like opioids, sedatives, antihypertensives; assess gait, balance, cognitive status; implement fall precautions
- Beers Criteria: list of medications to AVOID or use with caution in older adults (e.g., benzodiazepines, long-acting NSAIDs, certain anticholinergics); check before prescribing or administering
Key definitions
Pediatric Patient
Example
6-month-old weighs 8 kg; amoxicillin order 30 mg/kg = 30 × 8 = 240 mg; on hand suspension 125 mg/5 mL; give 240÷125 × 5 = 9.6 mL
Infant to adolescent; requires weight-based dosing (mg/kg) and careful monitoring due to immature organ systems and rapid physiologic changes.
Older Adult
Example
80-year-old on digoxin, metoprolol, lisinopril, aspirin; kidney function declining (Cr 1.8); digoxin t½ extended—risk of toxicity; start low, go slow
Age ≥65 years; altered pharmacokinetics (reduced hepatic metabolism, renal clearance); drugs accumulate; polypharmacy common.
Pharmacokinetic Changes in Older Adults
Example
Warfarin metabolism slowed; INR rises higher and stays elevated longer; requires closer monitoring and lower doses than younger patients
Decreased absorption, altered distribution, reduced hepatic metabolism, impaired renal excretion; result: slower onset, longer duration, drug accumulation.
Polypharmacy
Example
Patient on 10+ medications; diuretic + ACE inhibitor + NSAID → increased hyperkalemia risk; must check interactions carefully
Use of multiple medications; increases risk of drug interactions, adverse effects, and medication errors; common in older adults.
Diagrams to know
- Pediatric safe dose range verification checklist
- Older adult medication review framework
- Weight-based dosing calculation pathway for pediatrics
Safe Medication Administration Practices
Important facts
- NEVER leave oral medications at bedside unattended; patient must swallow in front of you to confirm administration
- If patient questions a medication ('I don't usually take this'), STOP and verify order—patient insight is valuable; do not give until verified
- ALWAYS check for ALLERGIES: ask directly, check allergy alert on chart, verify vs MAR; include food allergies (shellfish + penicillin cross-reaction possible)
- ASSESS BEFORE GIVING: check vital signs, relevant labs, patient status—e.g., apical pulse before digoxin, BP before antihypertensive, RR before opioid, glucose before insulin
- MEDICATION RECONCILIATION: at hospital admission, review ALL medications patient was taking at home; at discharge, provide updated list; at transfers between units, reconcile
- DOCUMENTATION: chart AFTER giving, not before; include: drug name, dose, route, time, site (if injection), patient response, patient education given, patient questions answered
- MEDICATION ERROR management: (1) STOP, (2) assess patient immediately, (3) notify prescriber and unit manager, (4) complete incident report, (5) continue monitoring, (6) do NOT hide or falsely document
- USE SAFE ABBREVIATIONS ONLY: write 'units' in full (not U); 'mcg' (not µ); use LEADING ZERO (0.5 mg not .5 mg); NEVER trailing zero (not 5.0 mg—dangerous in prescriptions)
- HIGH-ALERT DRUGS require TWO independent nurse checks before administration; both nurses verify patient, dose, calculation, expiration date
- LOOK-ALIKE/SOUND-ALIKE drug names: cefazolin vs cephalexin, atenolol vs albuterol, digoxin vs digitoxin—triple-check spelling and verify indication
Key definitions
Three Checks of the Label
Example
Acetaminophen order: check at drawer (is this acetaminophen?), at preparation (250 mg/5 mL?), at bedside (right patient, right amount?)
Safety protocol: check label (1) when removing from storage, (2) when preparing/measuring, (3) at bedside before administering; compares to physician's order each time.
Two-Identifier Verification
Example
Ask 'What is your full name and date of birth?' Compare answer to wristband and MAR; document verification in chart
Confirm patient identity using TWO independent identifiers (name + ID number or birthdate); not room number or bed assignment.
Medication Error
Example
Gave 2 tablets when order said 1 tablet; gave warfarin at 0800 instead of 1800; gave gentamicin to wrong patient
Any deviation from a correct medication dose, route, time, or patient; includes giving wrong drug or giving correct drug to wrong patient.
Incident Report (Adverse Event Report)
Example
After medication error, complete incident report with facts (time, drug, dose, what happened, patient response); notify supervisor; ensure patient safety first
Documentation of a medication error or adverse event; used for quality improvement, never for punishment; protected legal document.
Contraindication
Example
Patient allergic to penicillin = contraindication to amoxicillin; eGFR <30 = contraindication to many drugs without dose adjustment
Reason NOT to give a medication to a patient (e.g., allergy, low BP, liver disease, drug interaction).
Drug Interaction
Example
Warfarin + aspirin = increased bleeding risk; metformin + alcohol = risk of lactic acidosis; digoxin + loop diuretic = hypokalemia + digoxin toxicity
Effect of one drug on another when given together; may increase/decrease effect, or cause new adverse effect.
Diagrams to know
- The Three Checks pathway and timing
- Medication error response flowchart: assess → notify → report → document
- Pre-administration assessment checklist by drug class
Must remember
- D/H × Q formula: Dose = (Desired ÷ Have) × Quantity; ALWAYS convert to same unit first or you will give wrong dose
- Weight-based dosing: Always convert pounds to kg (÷ 2.2, never × 2.2); verify calculated dose is within SAFE DOSE RANGE before giving
- IV gtt/min = (Volume mL × Drop Factor gtt/mL) ÷ Time in minutes; round to whole number; microdrip = 60 gtt/mL
- THE TEN RIGHTS: Right patient (two identifiers, NOT room number), drug, dose, route, time, documentation (AFTER giving), reason, assessment, response, and refusal—all non-negotiable
- Three checks of the label: Remove from storage, during preparation, and at bedside before giving; compare to physician order EACH time
- NEVER give IV potassium (KCl) as IV push undiluted—FATAL; always dilute and infuse slowly via pump at ≤10 mEq/hr
- High-alert drugs (insulin, heparin, warfarin, opioids, KCl, chemotherapy) require independent DOUBLE-CHECK by two nurses; verify dose, calculation, patient, and expiration
- Safe abbreviations: Write 'units' in full (NOT U), 'mcg' (NOT µ), use LEADING ZERO (0.5 mg NOT .5 mg), NEVER trailing zero (NOT 5.0 mg)
- IV fluid tonicity: Isotonic (0.9% NaCl, LR) stays in ECF; hypotonic (0.45% NaCl) shifts INTO cells; hypertonic (3% NaCl) pulls fluid OUT—know which to use when
- Medication error management: Stop → assess patient → notify prescriber and manager → complete incident report → document honestly; PATIENT SAFETY is priority #1, never hide errors
Last minute tips
- Before EVERY exam, memorize the four unit conversions cold: 1 g = 1,000 mg; 1 mg = 1,000 mcg; 1 kg = 2.2 lb; 1 tsp = 5 mL. If you mix these up, you will fail the calculation questions.
- If an exam question says 'the nurse should...' for medication administration, the answer is almost ALWAYS one of the Rights (verify patient ID, check for allergy, assess before giving, chart after giving). When in doubt, choose the safest option and the most detailed verification step.
- For any IV infusion question, first IDENTIFY the formula: Is it mL/hr (pump) or gtt/min (gravity)? Then check if drop factor is given. If not given and it is gravity, assume 15 gtt/mL. Round gtt/min to whole number.
- Pediatric dosing questions: Always check if the answer matches the SAFE DOSE RANGE in a pediatric reference. If your calculated dose is 1,000 mg but the safe range is 100–300 mg, you made an error—recheck your math before answering.
- On the NLE, if you see 'the patient questions this medication,' the correct action is ALWAYS 'stop and verify the order,' NOT 'reassure the patient and give it.' Patient safety and verification come before reassurance.
Comparison tables
Routes of Administration: Comparison
| Route | Injection Angle | Max Volume | Onset Time | Best Sites | Key Precautions |
|---|---|---|---|---|---|
| Intradermal (ID) | 10–15° | ≤0.1 mL | 5–15 min | Forearm, inner arm | Forms bleb; for testing only |
| Subcutaneous (SC/SQ) | 45–90° | ≤1 mL | 15–30 min | Abdomen, arms, thighs | No aspiration/massage for heparin; rotate sites |
| Intramuscular (IM) | 90° | ≤3 mL (deltoid ≤1 mL) | 10–30 min | Ventrogluteal (safest), vastus lateralis, deltoid | Use Z-track for irritants; avoid dorsogluteal |
| Intravenous (IV) | 15–20° into vein | Unlimited | Immediate (seconds–5 min) | Veins: hand, forearm, upper arm, central line | Highest risk; strict asepsis; monitor for complications |
IV Fluid Tonicity: Osmolality and Clinical Use
| Fluid Type | Osmolality | Effect on Cells | Common Examples | When to Use | Contraindications |
|---|---|---|---|---|---|
| Isotonic | ~280 mOsm/L | No shift; expands ECF | 0.9% NaCl, LR, D5W (in bag) | Fluid replacement, dehydration, maintenance | None (safest); use first-line in most situations |
| Hypotonic | <280 mOsm/L | Pulls fluid INTO cells (cell swelling) | 0.45% NaCl, 0.33% NaCl | Cellular dehydration, hypernatremia | NEVER in increased ICP, head trauma, or post-neurosurgery |
| Hypertonic | >280 mOsm/L | Pulls fluid OUT of cells (cell shrinking) | 3% NaCl, D10W, D20W | Severe hypervolemia, cerebral edema, hyponatremia | Give SLOWLY via pump; risk of vein irritation; not with PO fluids |
High-Alert Medications: Monitoring and Antidotes
| Drug Class | Monitoring Parameter | Target Range/Goal | Antidote | Critical Precaution |
|---|---|---|---|---|
| Insulin | Blood glucose | 80–120 mg/dL (varies by protocol) | Glucagon (if hypoglycemia) | Use ONLY insulin syringes; 'clear before cloudy' when mixing |
| Heparin (unfractionated) | aPTT | 1.5–2.5× control | Protamine sulfate (1 mg per 100 units heparin) | Do NOT give IM; monitor for bleeding; check aPTT 4–6 hr after dose change |
| Warfarin | PT/INR | 2–3 (most indications; varies by condition) | Vitamin K (phytonadione) 2.5–10 mg | Onset 3–5 days; food/drugs affect INR; monitor for bleeding |
| Opioids | Respiratory rate, pain, sedation level | RR ≥12, pain controlled, alert/appropriate | Naloxone 0.4–0.8 mg IV/IM/IN | Hold if RR <12; assess before EVERY dose; watch for respiratory depression |
| Potassium chloride (IV) | Serum potassium | 3.5–5.0 mEq/L | None (NEVER give undiluted; cardiotoxic) | ALWAYS dilute; max infusion 10 mEq/hr; NEVER give IV push |
| Digoxin | Serum digoxin level, apical pulse, ECG | 0.5–2.0 ng/mL | Digoxin-specific Fab fragments (Digibind) | Check apical pulse ≥60 before giving; risk of toxicity in renal disease |
Medication Error: Prevention and Response
| Error Stage | High-Risk Situations | Prevention Strategies | If Error Occurs |
|---|---|---|---|
| Ordering Phase | Unclear handwriting, abbreviations, dose ambiguity | Verify order is legible and complete; clarify with prescriber if unsure; use only safe abbreviations | Assess patient immediately; notify prescriber and manager; no 'near miss' passes |
| Transcription Phase | Misreading order, transposition of digits, copying errors | Compare MAR to original order; double-check high-alert drugs; one nurse reads, other verifies | Document error with facts; complete incident report; monitor patient closely |
| Preparation Phase | Wrong drug selected, wrong dose calculated, expiration missed | Three checks; quiet environment; use computer/pump prompts; verify calculations twice | Do NOT give if error detected during prep; inform supervisor; reconcile with order |
| Administration Phase | Wrong patient, wrong time, wrong route, patient questions medicine | Two-identifier verification; three checks at bedside; listen to patient concerns; do not skip steps when busy | STOP immediately; assess patient; notify prescriber and manager right away; incident report required |
Pediatric vs Older Adult Medication Administration
| Aspect | Pediatrics | Older Adults |
|---|---|---|
| Dosing Approach | Weight-based (mg/kg); verify safe dose range BEFORE giving | Start low, go slow; reduce doses for reduced renal/hepatic clearance |
| Pharmacokinetics | Immature liver/kidneys; faster metabolism of some drugs; shorter half-lives | Reduced hepatic metabolism; reduced renal clearance; drugs accumulate; longer half-lives |
| Volume of Injection | SMALL (oral syringe mL, not household spoons); IM volume tiny; SC usually <0.5 mL | Standard volumes usually appropriate; assess ability to swallow/absorb |
| IM Site Selection | Ventrogluteal safe even for infants; vastus lateralis for <7 months; avoid deltoid in small children | Ventrogluteal safest; assess muscle mass and fragility; use smaller volume if needed |
| Monitoring Focus | Drug effects, growth/development, fluid intake/output, electrolytes | Drug interactions, renal/hepatic function, fall risk, polypharmacy complications, orthostatic hypotension |
| Error Risk | CRITICAL: calculation errors, wrong dose, wrong concentration; often FATAL | HIGH: drug interactions, underdosing/overdosing, adverse effects from accumulation |
Diagrams
Medication Dosage Calculation Flowchart
Complete flowchart showing the step-by-step process for safe medication dose calculation, from order verification through documentation. Includes decision points for unit conversion, weight-based dosing, and verification checks.
Rights of Medication Administration Mind Map
Comprehensive mind map organizing the Ten Rights of medication administration into logical categories: patient safety, drug information, dose/route/time, documentation/legal, and the critical three-check protocol.
IV Complication Recognition and Response
Decision tree for identifying and responding to common IV complications (infiltration, phlebitis, fluid overload, air embolism) based on clinical signs and appropriate immediate nursing interventions.
Medication Error Response Protocol
Step-by-step protocol for responding immediately and appropriately to any medication error, prioritizing patient safety, accurate reporting, and honest documentation.