11.2 Seven Rights & Dosage Calculations
Key Takeaways
- AMCA CMAC task 3.06.3 requires the seven rights of medication administration—not the older five-rights list alone.
- The seven rights are: right patient, right medication, right dose, right route, right time, right documentation, and right technique (or right reason/indication in some teaching sets—know the AMCA seven-rights framing for administration).
- Task 3.06.4 requires solid and liquid dosage calculations and weight-based dosing with unit conversion.
- Core formula: Desired ÷ Have × Quantity = amount to give; always convert units before calculating.
- If the math yields an unsafe or implausible dose, stop and clarify—do not force an answer that fails clinical sense.
3.06.3 — Seven Rights of Medication Administration
Many textbooks still open with five rights (patient, drug, dose, route, time). The AMCA CMAC blueprint explicitly says seven “rights.” Study and apply seven on this exam.
The Seven Rights (CMAC-Ready List)
| # | Right | What you verify |
|---|---|---|
| 1 | Right patient | Two identifiers (name + DOB/MRN); active verification, not a nod to a read-aloud name only |
| 2 | Right medication | Order vs label vs MAR three times (when pulling, preparing, and at bedside/chairside); watch LASA pairs |
| 3 | Right dose | Calculated and measured dose matches the order after unit conversion |
| 4 | Right route | PO vs IM vs SQ vs ID vs inhalation—never assume |
| 5 | Right time | Frequency, scheduled window, PRN indications, last-dose timing |
| 6 | Right documentation | Chart what was given, when, by whom, site/response; never document before giving |
| 7 | Right technique (often paired in teaching with right reason/indication) | Correct preparation, site, angle, asepsis, and that the drug is appropriate for the ordered indication; clarify odd orders |
Some nursing references list right reason, right response, or right to refuse as expanded rights. For CMAC stems, prioritize the blueprint’s seven rights of administration and do not stop at five.
Applying Rights in Sequence
- Identify the patient with two identifiers.
- Compare MAR/order to the medication label (drug name, strength, form).
- Perform dose calculation and measure carefully (scored tablet, oral syringe—not a household teaspoon for precision liquids when a syringe is indicated).
- Confirm route and time (e.g., not giving an AM daily drug at the wrong encounter without order).
- Use correct technique for that route (Section 11.3).
- Observe for immediate reaction as policy requires.
- Document promptly and completely; document refusal if the patient declines after education.
High-Yield “Rights” Traps
| Trap | Why it fails a right |
|---|---|
| Same last name in waiting room; call first name only | Wrong patient |
| Grabbing hydrALAZINE instead of hydrOXYzine | Wrong medication (LASA) |
| Giving 5 mL when calculation was 0.5 mL | Wrong dose |
| Injecting a drug labeled “for oral use only” | Wrong route |
| Second PRN opioid inside the forbidden interval | Wrong time |
| Charting the injection before it is given, then getting interrupted | Wrong documentation |
| IM into dorsogluteal without landmark skill / wrong needle for obese adult | Wrong technique |
Right to refuse: Competent adults may refuse. Educate on risks/benefits as directed, notify the provider, and document—do not force oral meds or hide drugs in food without an ethical/legal plan.
3.06.4 — Dosage Calculations
Unit Conversions to Memorize
| Conversion | Memory |
|---|---|
| 1 kg = 2.2 lb | Divide lb by 2.2 → kg; multiply kg by 2.2 → lb |
| 1 g = 1000 mg | Move decimal three places |
| 1 mg = 1000 mcg | Micrograms on pediatric/high-alert labels |
| 1 L = 1000 mL | Volume |
| 1 tsp ≈ 5 mL | Household approx—prefer oral syringe when precision matters |
| 1 tbsp ≈ 15 mL | Three teaspoons |
| 1 oz ≈ 30 mL | Fluid ounce |
Always convert to matching units before the formula. Do not mix mg with mL until you know the concentration (mg per mL).
Universal Formula (Solid or Liquid)
[ \frac{\text{Desired (D)}}{\text{Have (H)}} \times \text{Quantity (Q)} = \text{Amount to administer} ]
- Desired = ordered dose
- Have = dose on hand (what the label strength is)
- Quantity = form that contains the “Have” amount (1 tablet, 5 mL, 1 mL, etc.)
Worked Example 1 — Solid (Scored Tablet)
Order: Lisinopril 10 mg PO daily
On hand: Lisinopril 20 mg tablets (scored)
[ \frac{10\ \text{mg}}{20\ \text{mg}} \times 1\ \text{tablet} = 0.5\ \text{tablet} ]
Give one-half tablet if scoring and policy allow; if unscored and not designed to split, obtain correct strength—do not crush assumptions into unsafe practice.
Worked Example 2 — Liquid Oral
Order: Amoxicillin 250 mg PO
On hand: Amoxicillin suspension 125 mg / 5 mL
[ \frac{250\ \text{mg}}{125\ \text{mg}} \times 5\ \text{mL} = 10\ \text{mL} ]
Shake suspensions per label; measure with a calibrated oral syringe or cup at eye level.
Worked Example 3 — Injectable Concentration
Order: Ketorolac 30 mg IM
On hand: Ketorolac 15 mg/mL
[ \frac{30\ \text{mg}}{15\ \text{mg}} \times 1\ \text{mL} = 2\ \text{mL} ]
Select a syringe that can measure 2 mL accurately and a needle appropriate for IM (Section 11.3).
Worked Example 4 — Unit Conversion First
Order: Digoxin 0.125 mg PO
On hand: Digoxin 125 mcg tablets
Convert: 0.125 mg = 125 mcg.
[ \frac{125\ \text{mcg}}{125\ \text{mcg}} \times 1\ \text{tablet} = 1\ \text{tablet} ]
Failing to convert mg↔mcg is a classic exam (and real-world) error—0.125 mg is not 0.125 tablets of a 125 mcg product without conversion logic.
Worked Example 5 — Weight-Based Dose
Order: Cefdinir 7 mg/kg PO every 12 hours
Patient weight: 44 lb
On hand: 125 mg / 5 mL suspension
Step 1 — kg: [ 44\ \text{lb} \div 2.2 = 20\ \text{kg} ]
Step 2 — ordered mg: [ 7\ \text{mg/kg} \times 20\ \text{kg} = 140\ \text{mg per dose} ]
Step 3 — volume: [ \frac{140\ \text{mg}}{125\ \text{mg}} \times 5\ \text{mL} = 5.6\ \text{mL} ]
Give 5.6 mL per dose with a calibrated oral syringe (round only per facility rules and product instructions—do not round in a way that creates a 10× error).
Worked Example 6 — mg/kg with Maximum Check Mentality
Order: Acetaminophen 15 mg/kg PO once
Child: 22 lb (10 kg)
On hand: 160 mg / 5 mL
Dose in mg: (15 \times 10 = 150) mg.
Volume: [ \frac{150}{160} \times 5\ \text{mL} ≈ 4.7\ \text{mL} ]
Also think clinically: total daily acetaminophen limits matter for repeated dosing—flag duplicate acetaminophen products (cold combos) for the provider.
Ratio and Proportion Alternative
If you prefer proportions for Example 2:
[ \frac{125\ \text{mg}}{5\ \text{mL}} = \frac{250\ \text{mg}}{x\ \text{mL}} \Rightarrow x = 10\ \text{mL} ]
Same answer—pick one method and stay consistent under time pressure.
Insulin and High-Alert Awareness (Calculation Context)
- Insulin is usually ordered in units; use insulin syringes marked in units when drawing U-100 insulin.
- Never use a tuberculin syringe “because the numbers look similar” without training for that product.
- Independent double-checks are common policy for insulin and anticoagulants—welcome them.
Dimensional Analysis Mindset (Optional but Powerful)
Cancel units until only the administration unit remains:
[ 20\ \text{kg} \times \frac{7\ \text{mg}}{1\ \text{kg}} \times \frac{5\ \text{mL}}{125\ \text{mg}} = 5.6\ \text{mL} ]
If units do not cancel cleanly, the setup is wrong.
Safe Calculation Habits for Exam Day and Clinic
- Write units on every line.
- Convert first; calculate second; sense-check third.
- Recalculate if the volume is tiny (0.01 mL) or huge (30 mL IM)—likely a decimal error.
- Clarify illegible orders; do not guess trailing zeros or missing leading zeros (write 0.5 mg, never .5 mg; never 5.0 mg when policy bans trailing zeros for certain drugs).
- Apply seven rights after the number is correct—right math with wrong patient still harms.
CMAC Exam Traps for Tasks 3.06.3–3.06.4
- Answering with only five rights when the stem asks for the CMAC/blueprint seven.
- Documenting before administration.
- Using household teaspoons as if they were exact 5 mL lab measures for narrow therapeutic drugs without calibration.
- Forgetting lb → kg (using 44 lb as 44 kg explodes a pediatric dose).
- Mixing mg and mcg without converting.
- Calculating correctly but giving the drug by the wrong route or to the wrong patient.
Memory anchors: seven rights every dose; D/H × Q; convert units first; kg = lb/2.2; if the answer looks absurd, stop.
The AMCA CMAC blueprint requires which standard for medication administration checks?
Order: amoxicillin 400 mg PO. On hand: 200 mg/5 mL suspension. How much should the medical assistant administer?
A child weighs 33 lb. The order is 10 mg/kg of a liquid medication. What is the correct dose in milligrams before converting to mL?
Which action violates a medication “right” even if the dose calculation is correct?