Ptcb Quiz: Contraindications
20 questions · exam conditions
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ContraindicationsQuestion 1 of 20

A patient brings in a new prescription for sildenafil 50 mg. A review of their medication profile shows they are also taking sublingual nitroglycerin for angina.

Which of the following best explains why sildenafil is contraindicated for this patient?

The combination can cause severe, life-threatening hypotension.
Sildenafil can decrease the effectiveness of nitroglycerin.
The combination increases the risk of a myocardial infarction.
Nitroglycerin significantly increases sildenafil blood levels.
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Ptcb Quiz

Ptcb Quiz: Contraindications

Practice Contraindications in Ptcb with focused quiz questions that help you check what you know, review explanations, and build confidence with test-style prompts.

What this quiz covers

This quiz focuses on Contraindications, giving you a quick way to practice the rules, question types, and explanations that matter most for Ptcb.

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Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.

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Question 1

A patient brings in a new prescription for sildenafil 50 mg. A review of their medication profile shows they are also taking sublingual nitroglycerin for angina.

Which of the following best explains why sildenafil is contraindicated for this patient?

  1. The combination can cause severe, life-threatening hypotension. (correct answer)
  2. Sildenafil can decrease the effectiveness of nitroglycerin.
  3. The combination increases the risk of a myocardial infarction.
  4. Nitroglycerin significantly increases sildenafil blood levels.
Explanation: Sildenafil, a phosphodiesterase-5 (PDE-5) inhibitor, and nitrates like nitroglycerin are both vasodilators. Their concurrent use is absolutely contraindicated because it can lead to a synergistic drop in blood pressure, causing severe and potentially fatal hypotension.

Question 2

A patient's electronic health record indicates a history of angioedema. The pharmacy receives a new e-prescription for lisinopril.

The use of lisinopril is contraindicated in this patient due to which information in their record?

  1. A documented allergy to penicillin.
  2. A diagnosis of hypertension.
  3. A history of angioedema. (correct answer)
  4. Concurrent use of hydrochlorothiazide.
Explanation: A history of angioedema (swelling of the deeper layers of skin) is an absolute contraindication for the use of any ACE inhibitor, such as lisinopril, due to the high risk of a recurrent, life-threatening reaction. Hypertension is the indication for lisinopril, not a contraindication.

Question 3

A prescription for doxycycline 100 mg is presented for a 7-year-old child for the treatment of Lyme disease.

Use of doxycycline in this patient is generally contraindicated due to the risk of:

  1. liver toxicity.
  2. permanent tooth discoloration. (correct answer)
  3. stunted bone growth.
  4. severe allergic reaction.
Explanation: Tetracycline antibiotics, including doxycycline, are contraindicated in children under 8 years of age because they can bind to calcium in developing teeth, causing permanent yellow or brown discoloration and enamel hypoplasia. While sometimes used in severe cases like Rocky Mountain spotted fever, it is a significant contraindication to consider.

Question 4

A patient with a history of asthma controlled with albuterol presents a new prescription for propranolol to manage migraines.

Propranolol is contraindicated in this patient because it is a non-selective beta-blocker and can cause:

  1. an increase in blood pressure.
  2. a severe headache.
  3. bronchoconstriction. (correct answer)
  4. a rapid heart rate.
Explanation: Propranolol is a non-selective beta-blocker, meaning it blocks both beta-1 and beta-2 receptors. Blocking beta-2 receptors in the lungs can cause bronchoconstriction (narrowing of the airways), which can trigger a severe asthma attack. Therefore, it is contraindicated in patients with asthma.

Question 5

A patient's profile lists a severe, documented allergy to sulfonamides. The pharmacy receives a prescription for celecoxib (Celebrex) for arthritis pain.

Use of celecoxib is contraindicated in this patient because it:

  1. is a known P-glycoprotein inhibitor.
  2. contains a sulfonamide chemical group. (correct answer)
  3. is also a potent anticoagulant.
  4. can cause significant hyperkalemia.
Explanation: Celecoxib, although a COX-2 inhibitor, contains a sulfonamide moiety in its chemical structure. Therefore, it is contraindicated in patients with a known sulfa allergy due to the risk of a cross-reactivity allergic reaction, which can range from a rash to life-threatening anaphylaxis.

Question 6

A 25-year-old female patient with severe acne is prescribed isotretinoin. Her medical history indicates she is currently trying to conceive.

Isotretinoin is absolutely contraindicated in this patient because it:

  1. causes severe liver damage.
  2. is a potent teratogen. (correct answer)
  3. can lead to premature menopause.
  4. interacts with hormonal contraceptives.
Explanation: Isotretinoin is a known human teratogen, meaning it can cause severe birth defects if taken during pregnancy. It is absolutely contraindicated in patients who are pregnant or may become pregnant. Patients must be enrolled in the iPLEDGE REMS program, which requires strict pregnancy prevention measures before, during, and after therapy.

Question 7

A patient is admitted to the hospital with a deep vein thrombosis (DVT) and is found to be 12 weeks pregnant. A physician considers starting warfarin therapy.

Why is warfarin contraindicated in this pregnant patient?

  1. It can cause maternal hypertension.
  2. It is not effective for treating DVT during pregnancy.
  3. It crosses the placenta and can cause fetal harm. (correct answer)
  4. It significantly increases the risk of maternal bleeding.
Explanation: Warfarin is contraindicated during pregnancy (Pregnancy Category X) because it is a small molecule that can cross the placental barrier and act as a teratogen, causing fetal bleeding and birth defects (fetal warfarin syndrome). Low-molecular-weight heparin (LMWH) is the preferred anticoagulant in pregnancy.

Question 8

An elderly patient with chronic kidney disease (CKD) Stage 4 asks to purchase a large bottle of high-strength ibuprofen for arthritis pain.

Regular use of ibuprofen is contraindicated in this patient because NSAIDs can:

  1. increase the risk of blood clots.
  2. worsen kidney function. (correct answer)
  3. cause significant drowsiness.
  4. lead to medication dependence.
Explanation: Nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen can cause renal damage by constricting the afferent arterioles of the kidneys, thereby reducing blood flow. In a patient with pre-existing chronic kidney disease, this can lead to acute kidney injury or progression of their CKD. Therefore, their use is relatively or absolutely contraindicated depending on the severity of the disease.

Question 9

A patient with a history of gout is being treated with allopurinol. They are newly diagnosed with an autoimmune condition and prescribed azathioprine.

The concurrent use of allopurinol and azathioprine is contraindicated because allopurinol:

  1. decreases the absorption of azathioprine.
  2. blocks the metabolism of azathioprine, leading to toxicity. (correct answer)
  3. inactivates azathioprine, causing treatment failure.
  4. increases the risk of a gout flare.
Explanation: Allopurinol inhibits xanthine oxidase, an enzyme that is critical for the metabolism of azathioprine. Taking them together can lead to dangerously high levels of azathioprine's active metabolites, causing severe, life-threatening myelosuppression (bone marrow suppression). If co-administration is necessary, the azathioprine dose must be drastically reduced.

Question 10

A patient with active liver disease and elevated liver enzymes (AST/ALT) is given a new prescription for atorvastatin.

Atorvastatin is contraindicated in this patient due to their:

  1. high cholesterol levels.
  2. active liver disease. (correct answer)
  3. age over 65.
  4. history of diabetes.
Explanation: Statins, including atorvastatin, are contraindicated in patients with active liver disease or unexplained persistent elevations of serum transaminases. The liver is the primary site of action and metabolism for statins, and their use could exacerbate existing liver injury.

Question 11

A patient with narrow-angle glaucoma is looking for an over-the-counter medication for motion sickness and asks about dimenhydrinate.

Dimenhydrinate is contraindicated in this patient because its anticholinergic properties can:

  1. decrease tear production.
  2. cause sedation.
  3. increase intraocular pressure. (correct answer)
  4. lead to urinary retention.
Explanation: Drugs with anticholinergic effects, like dimenhydrinate, can cause pupillary dilation (mydriasis). In a patient with narrow-angle glaucoma, this can block the drainage of aqueous humor from the eye, leading to a sudden and dangerous increase in intraocular pressure, potentially causing vision loss.

Question 12

A patient taking amiodarone for atrial fibrillation is prescribed a new medication, sofosbuvir/velpatasvir (Epclusa), for Hepatitis C.

This combination is contraindicated without close monitoring due to the risk of:

  1. severe hepatotoxicity.
  2. QTc prolongation.
  3. symptomatic bradycardia. (correct answer)
  4. pulmonary fibrosis.
Explanation: Co-administration of amiodarone with certain direct-acting antiviral drugs for Hepatitis C, such as sofosbuvir, has been associated with cases of serious symptomatic bradycardia (a very slow heart rate), some requiring pacemaker intervention or leading to death. This combination carries a specific warning and is often considered a contraindication.

Question 13

A patient taking spironolactone for heart failure is prescribed a potassium chloride supplement for low potassium levels found on a recent lab test.

Administering these two medications together is contraindicated due to the high risk of developing:

  1. severe hyponatremia.
  2. life-threatening hyperkalemia. (correct answer)
  3. acute kidney failure.
  4. metabolic acidosis.
Explanation: Spironolactone is a potassium-sparing diuretic, meaning it works by blocking aldosterone, which causes the body to retain potassium. Administering a potassium supplement concurrently is contraindicated because the combination can lead to dangerously high levels of potassium in the blood (hyperkalemia), which can cause fatal cardiac arrhythmias.

Question 14

A patient with Class IV heart failure presents a new prescription for pioglitazone to manage their type 2 diabetes.

This medication is contraindicated for this patient because it can cause or worsen heart failure by:

  1. increasing blood glucose.
  2. causing fluid retention. (correct answer)
  3. decreasing heart rate.
  4. raising cholesterol levels.
Explanation: Thiazolidinediones (TZDs) like pioglitazone have a black box warning for causing or exacerbating congestive heart failure. They can cause fluid retention (edema), which increases the workload on the heart. For a patient with severe (Class III or IV) heart failure, this is an absolute contraindication.

Question 15

A patient is prescribed clozapine for treatment-resistant schizophrenia. The patient's absolute neutrophil count (ANC) from a recent blood test is 1,200/µL.

Initiating clozapine is contraindicated in this patient because of the:

  1. high risk of metabolic syndrome.
  2. potential for severe constipation.
  3. low absolute neutrophil count. (correct answer)
  4. risk of myocarditis.
Explanation: Clozapine carries a black box warning for severe neutropenia (agranulocytosis), a sharp drop in white blood cells that fight infection. Treatment initiation is contraindicated if the patient's baseline absolute neutrophil count (ANC) is less than 1,500/µL due to the risk of life-threatening infections.

Question 16

A patient with type 2 diabetes has lab results indicating severe renal impairment (eGFR < 30 mL/min/1.73m²). They have been taking metformin for several years.

The continued use of metformin is contraindicated in this patient due to the increased risk of:

  1. hypoglycemia.
  2. lactic acidosis. (correct answer)
  3. hyperkalemia.
  4. liver damage.
Explanation: Metformin is cleared by the kidneys. In patients with severe renal impairment, the drug can accumulate, increasing the risk of a rare but life-threatening side effect called lactic acidosis. Therefore, metformin is contraindicated in patients with an eGFR below 30.

Question 17

A pharmacy receives a request for an over-the-counter product containing pseudoephedrine for a patient with a medical history of uncontrolled hypertension.

Why is pseudoephedrine contraindicated for this patient?

  1. It can cause rebound congestion.
  2. It can further increase blood pressure. (correct answer)
  3. It interacts with common allergy medications.
  4. It can lead to drowsiness.
Explanation: Pseudoephedrine is a sympathomimetic agent that causes vasoconstriction, which can significantly increase blood pressure and heart rate. In a patient with already uncontrolled hypertension, this can be dangerous and is therefore contraindicated.

Question 18

A patient taking phenelzine, a monoamine oxidase inhibitor (MAOI), for depression is prescribed sertraline, a selective serotonin reuptake inhibitor (SSRI), by a new provider.

The concurrent use of these two medications is contraindicated due to the high risk of developing:

  1. neuroleptic malignant syndrome.
  2. serotonin syndrome. (correct answer)
  3. a hypertensive crisis.
  4. extrapyramidal symptoms.
Explanation: Combining an MAOI with an SSRI is contraindicated because both medications increase serotonin levels in the brain. Their combined effect can lead to dangerously high serotonin levels, causing serotonin syndrome, a potentially fatal condition characterized by confusion, agitation, rapid heart rate, and high blood pressure.

Question 19

A patient profile shows a new prescription for simvastatin and an existing prescription for itraconazole, an antifungal agent.

Concurrent use of these two medications is contraindicated because it significantly increases the risk of:

  1. liver failure.
  2. gastrointestinal bleeding.
  3. serotonin syndrome.
  4. rhabdomyolysis. (correct answer)
Explanation: Itraconazole is a strong inhibitor of the CYP3A4 enzyme, which is responsible for metabolizing simvastatin. Co-administration leads to very high levels of simvastatin in the blood, drastically increasing the risk of myopathy and its severe form, rhabdomyolysis (muscle breakdown), which can cause kidney failure.

Question 20

A patient with myasthenia gravis, a neuromuscular disease, is prescribed ciprofloxacin for a urinary tract infection.

Fluoroquinolone antibiotics like ciprofloxacin are contraindicated in this patient because they have a black box warning for:

  1. causing tendon rupture.
  2. exacerbating muscle weakness. (correct answer)
  3. inducing peripheral neuropathy.
  4. leading to mental status changes.
Explanation: Fluoroquinolones have a black box warning stating they may exacerbate muscle weakness in persons with myasthenia gravis. This is a serious contraindication, and alternative antibiotics should be used for patients with this condition.