Topic primers
A quick on-ramp for each area: the handful of facts that anchor it. Read one, then go practice. These are a launchpad, not a lecture.
PRIMER · Federal Requirements
Federal requirements, the essentials
- Schedule I has no accepted medical use; Schedules II to V step down in abuse potential.
- Schedule II prescriptions cannot be refilled; III and IV allow up to 5 refills within 6 months.
- DEA forms: 222 orders C-I/C-II stock, 106 reports theft or loss, 41 records destruction.
- An emergency oral Schedule II order needs a written follow-up within 7 days.
- Sublingual nitroglycerin is exempt from child-resistant packaging.
PRIMER · Order Entry & Processing
Order entry and calculations
- Days supply = total quantity / amount used per day.
- Convert pounds to kilograms (lb / 2.2) before weight-based dosing.
- Percent w/v means grams per 100 mL (5% = 5 g per 100 mL).
- IV rate (mL/hr) = total volume / time; gtt/min = (volume x drop factor) / minutes.
- An NDC has three parts: labeler, product, package.
PRIMER · Medications
Medications, patterns first
- Class suffixes: -pril is an ACE inhibitor, -sartan an ARB, -olol a beta blocker, -statin a statin.
- ACE inhibitors classically cause a dry cough; ARBs do not.
- Warfarin is monitored by INR; metformin is held around IV iodinated contrast.
- One generic can carry several brands (albuterol is ProAir, Ventolin, Proventil).
- Unopened insulin is refrigerated until it expires, never frozen.
PRIMER · Patient Safety & Quality Assurance
Patient safety essentials
- High-alert means severe harm if used in error (insulin, heparin, opioids, concentrated electrolytes).
- Tall-man lettering distinguishes look-alikes (DOPamine vs DOBUTamine).
- Do Not Use: write 'unit' not 'U', no trailing zero (5 mg), always a leading zero (0.5 mg).
- MedWatch Form 3500 is voluntary; Form 3500A is mandatory.
- A near-miss is caught before harm; a sentinel event reaches the patient with serious harm.
PRIMER · Order Entry & Processing
Pharmacy calculations survival kit
- Days supply = total quantity / amount used per day; round down to whole days.
- Ratio strength 1:1000 = 1 g in 1000 mL = 1 mg/mL.
- Dilution: C1 x V1 = C2 x V2; solve for the unknown volume, then qs with diluent.
- Alligation parts: high-strength parts = desired - low; low-strength parts = high - desired.
- gtt/min = (volume in mL x drop factor) / total minutes; round to whole drops.
PRIMER · Patient Safety & Quality Assurance
Sterile compounding and USP standards
- USP <795> covers nonsterile, <797> sterile, and <800> hazardous drug compounding.
- Garb dirtiest-to-cleanest; sterile gloves go on last, inside the clean area.
- A laminar airflow hood provides ISO Class 5 air; a HEPA filter removes at least 99.97% of 0.3-micron particles.
- Disinfect the direct compounding area with sterile 70% IPA at least every 30 minutes during compounding.
- A beyond-use date (BUD) applies to the compounded preparation, not the manufacturer's expiration date.
PRIMER · Federal Requirements
Controlled substances at the counter
- Schedule II: no refills, and no phoned-in orders except a genuine emergency.
- Schedule III-IV: up to 5 refills within 6 months of the issue date.
- Order Schedule I-II stock with DEA Form 222 or its electronic equivalent, CSOS.
- A DEA number has a built-in checksum you can verify from the digits.
- Watch for red flags: early refills, cash for large opioid quantities, prescribers far from the patient.
PRIMER · Medications
Top drug classes cheat sheet
- ACE inhibitors (-pril) and ARBs (-sartan) lower blood pressure; ACE inhibitors can cause a dry cough.
- Beta blockers (-olol) slow the heart rate; statins (-statin) lower cholesterol.
- PPIs (-prazole) and H2 blockers (-tidine) reduce stomach acid.
- Benzodiazepines (-pam, -lam) are Schedule IV; SSRIs treat depression and anxiety.
- Opioids relieve pain and are controlled; watch for respiratory depression and constipation.
PRIMER · Order Entry & Processing
Insurance and billing basics
- A 'refill too soon' rejection means too much of the prior fill remains; wait for the plan's allowed date.
- DAW 0 = substitution allowed; DAW 1 = prescriber requires brand; DAW 2 = patient requests brand.
- A copay is a fixed amount per fill; a deductible is what the patient pays before coverage begins.
- Prior authorization requires the prescriber to justify a drug before the plan will cover it.
- AWP (Average Wholesale Price) is a common reimbursement benchmark (e.g., AWP minus a percent, plus a fee).
PRIMER · Patient Safety & Quality Assurance
Medication safety at a glance
- High-alert drugs (insulin, heparin, opioids, concentrated electrolytes) cause severe harm if misused; double-check them.
- Look-alike/sound-alike names use tall-man lettering to tell them apart (hydrALAZINE vs hydrOXYzine).
- Avoid error-prone abbreviations: U (write 'unit'), IU, QD/QOD, and MS; spell them out.
- Use a leading zero (0.5 mg) and no trailing zero (5 mg) to prevent 10-fold dosing errors.
- The rights of medication use: right patient, drug, dose, route, and time (plus documentation).
PRIMER · Order Entry & Processing
Reading a prescription
- Common sig codes: PO (by mouth), BID/TID/QID (2/3/4 times daily), PRN (as needed), HS (at bedtime), q6h (every 6 hours).
- Required elements: patient name, date, drug and strength, directions (sig), quantity, refills, and prescriber signature.
- Days supply = total quantity / amount used per day; round down to whole days.
- AC = before meals, PC = after meals, stat = immediately.
- Verify the quantity matches the sig (1 capsule three times daily for 10 days = 30 capsules).
PRIMER · Medications
Interactions and counseling
- Grapefruit juice inhibits CYP3A4 and raises levels of drugs like simvastatin.
- Warfarin plus aspirin or NSAIDs increases bleeding risk; acetaminophen is the safer OTC pain option.
- ACE inhibitors can cause a dry cough; an ARB is a common alternative.
- Tetracyclines and fluoroquinolones cause photosensitivity; advise sun protection.
- Doxycycline and levothyroxine absorption drops with calcium, iron, or antacids; separate the doses.