DHA Pharmacy & Medication Management 2 — Questions and Answers

Question 1: Under DHA medication management standards, which category of medications requires an independent double-check before administration?

All oral medications
High-alert medications including concentrated electrolytes, insulin, heparin, and neuromuscular blocking agents (Correct answer)
Medications prescribed by resident physicians only
All antibiotics

Correct answer: High-alert medications including concentrated electrolytes, insulin, heparin, and neuromuscular blocking agents

High-alert medications (ISMP/DHA list) require an independent double-check — two separate nurses independently verify drug, dose, concentration, rate, and patient identity before administration. This significantly reduces errors with medications that have the highest potential for serious harm.

Independent double-check for high-alert medications: two nurses independently perform the check (without one telling the other the answer). Verify: right patient (two identifiers), right medication (name, expiry), right dose (calculation), right concentration, right route, right rate (for infusions), right pump programming. High-alert medications requiring double-check: concentrated electrolytes (KCl, KPO4, hypertonic NaCl), insulin (all types and routes), heparin/LMWH (intravenous), neuromuscular blocking agents, chemotherapy. Some hospitals also include PCA opioids. DHA and JCI require this as a mandatory safety standard.

Question 2: A pharmacy receives a prescription for methotrexate 2.5mg daily (written as 'QD') for a cancer patient. What is the pharmacist's primary safety concern?

The dose is too low for cancer treatment
Methotrexate should only be given intravenously
Methotrexate for non-cancer indications (RA, psoriasis) is typically weekly — daily dosing is a common fatal prescribing error; the indication must be verified before dispensing (Correct answer)
The 2.5mg tablet strength is not available commercially

Correct answer: Methotrexate for non-cancer indications (RA, psoriasis) is typically weekly — daily dosing is a common fatal prescribing error; the indication must be verified before dispensing

Methotrexate is one of the most common causes of fatal medication errors. For RA and psoriasis, it is given WEEKLY — patients or prescribers mistakenly prescribe it daily, causing fatal bone marrow suppression. The pharmacist must verify the indication. For cancer, daily dosing may be appropriate — but this must be explicitly confirmed.

Methotrexate fatality risk: for RA/psoriasis: once WEEKLY (typical doses 7.5–25mg/week); daily dosing causes cumulative toxicity — bone marrow suppression (fatal pancytopenia), mucositis, hepatotoxicity, pulmonary toxicity. The error: 'take daily' vs. 'take weekly' — miscommunication leads to daily dosing, multiple deaths reported globally. Pharmacist action: if indication unclear, STOP dispensing, contact prescriber. Clarify: cancer vs. non-cancer indication. Dispense with clear 'ONCE WEEKLY — NOT DAILY' labeling for RA/psoriasis. DHA and WHO have issued safety alerts specifically for methotrexate oral weekly dosing.

Question 3: In the context of medication reconciliation, when is it most critical to perform this process to prevent adverse drug events?

Only during discharge from hospital
Only in the ICU
At all care transitions: admission, transfer between units, and discharge (Correct answer)
Once monthly during medication review clinics only

Correct answer: At all care transitions: admission, transfer between units, and discharge

Medication reconciliation must be performed at ALL care transitions — hospital admission (compare home medications with admission orders), transfers between units (especially ICU to ward), and discharge (ensure medications are appropriately continued, stopped, or changed with patient counseling). Discrepancies at transitions are a leading cause of adverse drug events.

Medication reconciliation process: Collect (accurate medication history including OTC, herbals, doses, frequency, last dose); Reconcile (compare with orders at transition — identify omissions, duplications, interactions, dose changes, new medications); Communicate (explain changes to patient and next provider); Update (document in medication administration record). Errors at transitions: omissions (most common — 50%), wrong dose, wrong frequency, drug-drug interactions. IPSG 3 (JCI): improve safety of high-alert medications — reconciliation is a key component. DHA standards require medication reconciliation at all care transitions.

Question 4: A patient is prescribed gentamicin 5mg/kg/day once daily. The patient weighs 80kg and has a normal eGFR of 75 mL/min. What dose should the patient receive?

320 mg once daily
200 mg once daily
400 mg once daily (Correct answer)
160 mg once daily

Correct answer: 400 mg once daily

Gentamicin dose = 5 mg/kg × 80 kg = 400 mg once daily. For once-daily (extended interval) dosing in patients with near-normal renal function, the full weight-based dose is given as a single daily dose, which maximizes the concentration-dependent killing and allows adequate time for renal clearance.

Gentamicin once-daily dosing (Hartford nomogram): 5–7 mg/kg/day. Dose calculation: 5 mg/kg × 80 kg = 400 mg. Extended interval dosing rationale: aminoglycosides show concentration-dependent killing (higher peak = better bacterial kill) and post-antibiotic effect (continued killing after concentration drops). Once-daily dosing maximizes peak:MIC ratio, reduces nephrotoxicity (less accumulation in proximal tubule cells). Monitoring: check trough at 6–14 hours post-dose and plot on Hartford nomogram to determine interval (24h/36h/48h). Adjust for renal impairment (eGFR <60 — extend interval). DHA pharmacy practice exam tests aminoglycoside dosing calculations.

Question 5: Which of the following correctly describes the mechanism of action of proton pump inhibitors (PPIs)?

They neutralize stomach acid by acting as bases
They competitively block H2 histamine receptors on parietal cells
They irreversibly inhibit the H+/K+ ATPase (proton pump) on the luminal surface of gastric parietal cells (Correct answer)
They reduce gastrin secretion from G cells

Correct answer: They irreversibly inhibit the H+/K+ ATPase (proton pump) on the luminal surface of gastric parietal cells

PPIs (omeprazole, lansoprazole, pantoprazole, etc.) irreversibly inhibit the H+/K+ ATPase enzyme (proton pump) on the canalicular membrane of gastric parietal cells. This is the final common pathway for acid secretion, making PPIs the most effective acid suppressants. Acid suppression lasts until new proton pumps are synthesized (~18–24 hours).

PPIs: pro-drugs activated in acidic environment (canalicular secretory space) → form sulfenamide reactive intermediate → covalently (irreversibly) bind cysteine residues of H+/K+ ATPase. Duration of effect: acid suppression persists until new proton pump protein synthesis (18–24 hours) — hence once-daily dosing effective. Best taken 30–60 min before first meal (maximizes number of active pumps). H2 blockers (ranitidine, famotidine): reversibly block H2 receptors — less potent, develop tolerance. Antacids: neutralize existing acid. PPIs most effective for GERD, peptic ulcer, H. pylori eradication, Zollinger-Ellison syndrome.

Question 6: What is the appropriate storage temperature for insulin that is currently in use (opened vial/pen)?

Frozen (-20°C to -10°C)
Refrigerated (2°C to 8°C) continuously
Room temperature (up to 25–30°C) for up to 28–30 days after opening (Correct answer)
Only refrigerated overnight; room temperature during day

Correct answer: Room temperature (up to 25–30°C) for up to 28–30 days after opening

Opened insulin vials and pens can be stored at room temperature (up to 25–30°C depending on insulin type) for 28–30 days. Refrigeration of opened insulin is acceptable but cold insulin injected immediately can cause discomfort. Unopened insulin stock must be refrigerated (2–8°C) and not frozen.

Insulin storage: Unopened stock: refrigerate 2–8°C (never freeze — freezing destroys activity), protect from direct light. In-use: room temperature up to 25–30°C for 28 days (most regular, NPH, analog insulins) — some premixed insulins 14 days. Avoid: direct sunlight, heat >37°C. Signs of degraded insulin: discoloration, cloudiness in normally clear preparations, clumping. Patient education: do not inject cold insulin from fridge (discomfort + variable absorption); discard in-use pen/vial after 28–30 days regardless of remaining amount. DHA-licensed pharmacists provide insulin storage counseling as part of diabetes education.

DHA Pharmacy & Medication Management 2

Under DHA medication management standards, which category of medications requires an independent double-check before administration?