NAPLEX Question of the Week: Aiming for Appropriate Administration

This week's question assesses an all important component of the NAPLEX: Administration
NAPLEX Question of the Week: Aiming for Appropriate Administration

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You are the staff pharmacist at Green Hospital and receive several orders for a patient. You check to see what type of IV access the patient has and determine that they have peripheral access through a PVC (peripheral venous catheter). Which of the following medications in this patient’s order set are appropriate for administration through his peripheral line (assuming given separately from one another)?

A. Potassium chloride 40mEq/hour

B. TPN formula – 1200 mOsm/L

C. Zosyn

D. Insulin regular infusion

E. Calcium chloride


There are two major types of IV access in the hospital setting: peripheral and central. Peripheral lines are inserted into a smaller vein in the periphery (arms, legs). Central lines are inserted into larger veins such as the superior vena cava. They may still be inserted peripherally (such as PICC lines) as long as their tip ends in a larger vein. Certain drugs such as vesicants (drugs irritating to the skin) should typically be administered centrally due to a lower risk of the drug leaking out of the blood vessel and causing irritation to the skin (extravasation). Knowing recommendations for which drugs should be administered in which location is an important recommendation for a pharmacist.

Answer A is incorrect. Potassium chloride can be administered via either peripheral or central IV lines. However, it is the concentration and rate of administration to watch out for with potassium. Any concentration >20mEq/100mL should generally be administered via a central line rather than a peripheral line as well as any rate faster than 10mEq/hour. Even with administering potassium chloride at a rate higher than 10mEq/hour via a central line patients should be monitored with an EKG. This is due to the high risk of fast administration of potassium with causing cardiac arrest and death. This is also why potassium should never be administered undiluted or via IV push.

Answer B is incorrect. TPN is another drug that can be given via peripheral or central IV access. However, there are certain stipulations around the length of time and level of osmolarity that can be given via each route. If TPN will be used for longer than 2 weeks, it should be given centrally due to lower risk of infection. If TPN has an osmolarity over 900mOsm/L (some institutions will vary slightly on this number) it should also be given centrally due to administering the drug in a larger volume of blood.

Answer C is correct. Zosyn is an extended spectrum penicillin used quite frequently in the hospital to treat many different infections. Zosyn is safe to be administered peripherally.

Answer D is correct. Insulin, especially regular insulin, is given frequently in the hospital setting for blood glucose over 180mg/dL. Insulin is also safe to be given peripherally.

Answer E is incorrect. Calcium chloride should be given centrally due to the risk of tissue necrosis if extravasated. Calcium gluconate has a lesser risk of this and can be administered peripherally.

Brand/Generics included:

Potassium chloride (potassium chloride PROAMP); Zosyn (piperacillin-tazobactam); Insulin regular (Humulin R)


Potassium chloride package insert –

Zosyn package insert –

Insulin package insert –

Calcium chloride package insert –

NAPLEX Competencies Covered:

2.1 – Pharmacology, mechanism of action, or therapeutic class

2.2 – Commercial availability; prescription or non-prescription status; brand, generic, or biosimilar names; physical descriptions; or how supplied

3.5 – Drug route of administration, dosage forms, or delivery systems

5.5 – Instructions or techniques for drug administration

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