- Concurrent use of these two medications is contraindicated because it significantly increases the risk of:
Answer: rhabdomyolysis.
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.
- The concurrent use of allopurinol and azathioprine is contraindicated because allopurinol:
Answer: blocks the metabolism of azathioprine, leading to toxicity.
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.
- Which of the following best explains why sildenafil is contraindicated for this patient?
Answer: The combination can cause severe, life-threatening hypotension.
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.
- Administering these two medications together is contraindicated due to the high risk of developing:
Answer: life-threatening hyperkalemia.
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.
- Dimenhydrinate is contraindicated in this patient because its anticholinergic properties can:
Answer: increase intraocular pressure.
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.
- The concurrent use of these two medications is contraindicated due to the high risk of developing:
Answer: serotonin syndrome.
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.
- Isotretinoin is absolutely contraindicated in this patient because it:
Answer: is a potent teratogen.
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.
- Why is warfarin contraindicated in this pregnant patient?
Answer: It crosses the placenta and can cause fetal harm.
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.
- Initiating clozapine is contraindicated in this patient because of the:
Answer: low absolute neutrophil count.
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.
- The continued use of metformin is contraindicated in this patient due to the increased risk of:
Answer: lactic acidosis.
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.
- Propranolol is contraindicated in this patient because it is a non-selective beta-blocker and can cause:
Answer: bronchoconstriction.
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.
- Why is pseudoephedrine contraindicated for this patient?
Answer: It can further increase blood pressure.
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.
- Regular use of ibuprofen is contraindicated in this patient because NSAIDs can:
Answer: worsen kidney function.
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.
- Use of doxycycline in this patient is generally contraindicated due to the risk of:
Answer: permanent tooth discoloration.
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.
- Atorvastatin is contraindicated in this patient due to their:
Answer: active liver disease.
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.
- Fluoroquinolone antibiotics like ciprofloxacin are contraindicated in this patient because they have a black box warning for:
Answer: exacerbating muscle weakness.
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.
- The use of lisinopril is contraindicated in this patient due to which information in their record?
Answer: A history of angioedema.
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.
- Use of celecoxib is contraindicated in this patient because it:
Answer: contains a sulfonamide chemical group.
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.
- This medication is contraindicated for this patient because it can cause or worsen heart failure by:
Answer: causing fluid retention.
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.
- This combination is contraindicated without close monitoring due to the risk of:
Answer: symptomatic bradycardia.
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.
