PTCB Practice Test

Most Missed PTCB Questions

These are the PTCB practice questions that people on Tigertest get wrong most often, from the answers of 10 people. Each one shows the share who missed it, the right answer and why.

Updated 2026-11-12 by the Tigertest team. Weighted to the PTCB PTCE content outline effective January 2026. Federal law only; state rules vary.

1. 32% of people missed this (19 answers)

   1. Januvia (sitagliptin), taken once daily for type 2 diabetes, belongs to which drug class?

   • A.SGLT2 inhibitor
   • B.DPP-4 inhibitor
   • C.Thiazolidinedione
   • D.Biguanide

   Answer: B. Sitagliptin is a dipeptidyl peptidase-4 (DPP-4) inhibitor, recognized by the -gliptin suffix. Metformin is the biguanide, pioglitazone is a thiazolidinedione, and SGLT2 inhibitors end in -gliflozin (empagliflozin, Jardiance).

2. 33% of people missed this (18 answers)

   2. A technician receives a prescription for sildenafil for a patient whose profile lists isosorbide mononitrate. Why is this combination contraindicated?

   • A.Risk of dangerously high potassium
   • B.Sildenafil blocks nitrate absorption
   • C.Risk of serious bleeding
   • D.Risk of severe low blood pressure

   Answer: D. PDE5 inhibitors (sildenafil, tadalafil, vardenafil) and nitrates both dilate blood vessels, and together they can drop blood pressure dangerously. High potassium is the concern with ACE inhibitors plus potassium supplements, not this pair.

3. 60% of people missed this (10 answers)

   3. A technician compounds a preserved aqueous oral suspension on March 1 with no stability data. Using the USP <795> default, what is the beyond-use date?

   • A.April 5
   • B.March 15
   • C.March 31
   • D.May 30

   Answer: A. USP <795> gives preserved aqueous preparations a default BUD of 35 days, and March 1 plus 35 days (March has 31 days) is April 5. March 15 is the 14-day refrigerated limit for nonpreserved aqueous forms, and May 30 is the 90-day limit for nonaqueous forms.

4. 32% of people missed this (19 answers)

   4. A pharmacy is discarding an expired bulk container of warfarin at a concentration above 0.3%. Under RCRA, how is this waste classified?

   • A.U-listed toxic hazardous waste
   • B.Non-hazardous pharmaceutical waste
   • C.P-listed acutely hazardous waste
   • D.Trace chemotherapy waste

   Answer: C. Warfarin above 0.3% is on the EPA P-list (P001), which covers acutely hazardous discarded commercial chemical products such as physostigmine and arsenic trioxide. The U-list covers toxic products, including warfarin at 0.3% or less, so the U-list choice is the tempting wrong answer; states may add stricter rules (varies by state).

5. 33% of people missed this (18 answers)

   5. A patient brings leftover oxycodone tablets to a pharmacy that is not registered with DEA as a collector. What should the technician do?

   • A.Accept the tablets and return them to stock
   • B.Accept the tablets and record them on Form 41
   • C.Refer the patient to a registered collector or take-back event
   • D.Accept the tablets and send them to the pharmacy's reverse distributor

   Answer: C. Only DEA-registered collectors (through a collection receptacle or mail-back program) and law enforcement take-back events may accept patient-owned controlled substances, which are never pharmacy inventory. Returning them to stock or mixing them into the pharmacy's own waste or reverse-distributor returns is not permitted, and even at a registered collector staff may not count or sort receptacle contents.