Contraindications And Precautions - NAPLEX

1. Which drug class is contraindicated with any nitrate therapy due to profound hypotension risk?

   PDE5 inhibitors (e.g., sildenafil, tadalafil, vardenafil). These drugs potentiate the vasodilatory effects of nitrates through cGMP accumulation, risking severe cardiovascular collapse.

2. What is the major contraindication for isotretinoin related to patient factors?

   Pregnancy. Isotretinoin is highly teratogenic, causing severe birth defects such as craniofacial and cardiac abnormalities in exposed fetuses.

3. Which condition is a contraindication to using nonselective beta-blockers in asthma?

   Bronchospastic disease (e.g., asthma) for nonselective beta-blockers. Nonselective agents block beta-2 receptors in the lungs, potentially triggering bronchoconstriction and acute respiratory distress.

4. Which antibiotic class is contraindicated with tizanidine due to severe hypotension and sedation risk?

   Fluoroquinolones (especially ciprofloxacin). Fluoroquinolones inhibit CYP1A2, elevating tizanidine levels and intensifying its alpha-2 agonist effects on blood pressure and CNS.

5. What is the contraindication regarding nitrates and phosphodiesterase-5 inhibitors (PDE5 inhibitors)?

   Do not combine due to severe hypotension risk. Both agents cause vasodilation, leading to additive effects that can result in life-threatening drops in blood pressure.

6. Which antihypertensive class is contraindicated in pregnancy due to fetal renal toxicity?

   ACE inhibitors and ARBs. They cross the placenta and disrupt fetal kidney development, causing oligohydramnios, renal failure, and developmental anomalies.

7. Which migraine medication class is contraindicated in hemiplegic or basilar migraine?

   Triptans. These subtypes involve cerebral vasoconstriction risks, and triptans' serotonergic effects may worsen neurological complications.

8. Which medication is contraindicated in patients with severe hepatic impairment due to hepatotoxicity risk?

   Terbinafine (systemic) is contraindicated in chronic or active liver disease. Terbinafine undergoes hepatic metabolism and can cause idiosyncratic liver injury, worsening outcomes in pre-existing liver conditions.

9. What is the contraindication for combining an MAOI with an SSRI or SNRI?

   Do not combine due to serotonin syndrome risk. MAOIs inhibit serotonin breakdown, and combining with reuptake inhibitors leads to excessive serotonin accumulation and toxicity.

10. What is the contraindication for ACE inhibitors during pregnancy?

    Pregnancy (fetotoxicity, especially in $2^\text{nd}$ and $3^\text{rd}$ trimesters). These agents inhibit fetal renin-angiotensin system development, leading to renal agenesis, oligohydramnios, and skull hypoplasia.

11. What term describes a situation in which a drug should never be given due to high risk?

    Absolute contraindication. This term indicates scenarios where the potential harm from the drug far exceeds any therapeutic benefit, necessitating complete avoidance.

12. Which antidepressant is contraindicated in patients with seizure disorder or eating disorders?

    Bupropion. It lowers the seizure threshold and can exacerbate eating disorders by promoting weight loss or triggering binge-purge behaviors.

13. What is the contraindication for giving live vaccines to severely immunocompromised patients?

    Live vaccines are contraindicated in severe immunocompromise. These vaccines contain viable pathogens that can cause disseminated infection in patients with impaired immune responses.

14. Which opioid is contraindicated in patients taking MAOIs or within 14 days due to serotonin toxicity risk?

    Meperidine. Meperidine's metabolite inhibits serotonin reuptake, and MAOIs prevent serotonin degradation, causing potentially fatal serotonin syndrome.

15. Which antibiotic is contraindicated in infants due to risk of kernicterus?

    Sulfonamides (e.g., sulfamethoxazole) in infants. Sulfonamides displace bilirubin from albumin, leading to unbound bilirubin deposition in the brain and neurologic damage.

16. Which anticoagulant is contraindicated in patients with a history of heparin-induced thrombocytopenia (HIT)?

    Heparin (including LMWH). Prior exposure can trigger immune-mediated platelet destruction, risking severe thrombocytopenia and thrombosis upon re-exposure.

17. What is the contraindication for using a triptan in a patient with established coronary artery disease?

    Triptans are contraindicated in ischemic heart disease. Triptans cause vasoconstriction, which can exacerbate ischemia and precipitate myocardial infarction in vulnerable patients.

18. What is the contraindication for metformin related to acute clinical status?

    Acute metabolic acidosis (including diabetic ketoacidosis). Metformin impairs lactate clearance, exacerbating acidosis and increasing the risk of life-threatening lactic acidosis.

19. Which medication is contraindicated in patients with a known prolonged QT syndrome due to torsades risk?

    Dofetilide is contraindicated in congenital or marked QT prolongation. Dofetilide blocks potassium channels, further prolonging QT interval and increasing susceptibility to ventricular arrhythmias.

20. Which pregnancy category is absolutely contraindicated in pregnancy under the legacy FDA system?

    Category X. Studies in animals or humans demonstrate fetal abnormalities, with risks to the fetus outweighing any potential maternal benefits.

21. What is the contraindication for using NSAIDs in the setting of recent coronary artery bypass graft surgery?

    NSAIDs are contraindicated for perioperative pain in CABG surgery. NSAIDs inhibit prostaglandins, increasing cardiovascular events like myocardial infarction in the vulnerable post-surgical period.

22. What is the key difference between an absolute contraindication and a precaution?

    Contraindication: do not use; precaution: use with monitoring or adjustment. This distinction ensures patient safety by prohibiting drug use when risks outweigh benefits, while allowing cautious administration with oversight in less severe scenarios.

23. Which vaccine type is contraindicated during pregnancy in general (unless specific guidance exists)?

    Live attenuated vaccines. These vaccines pose a risk of fetal infection or harm due to potential replication of attenuated organisms across the placenta.

24. What is the contraindication for using clopidogrel with omeprazole or esomeprazole?

    Avoid combination due to reduced clopidogrel activation (CYP2C19 inhibition). These PPIs inhibit CYP2C19, impairing conversion of clopidogrel to its active metabolite and reducing antiplatelet efficacy.

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