COX-2 Inhibitors: Uses, Action & Risks

• Second-generation NSAIDs like COX-2 inhibitors are used to treat mild to moderate pain.
• COX-2 inhibitors also reduce fever and inflammation, and alleviate dysmenorrhea pain.
• Celecoxib is the prototype COX-2 inhibitor.

Pharmacologic Action

• COX-2 inhibitors were created to minimize COX-1 related adverse reactions affecting the stomach, kidneys, and platelets.
• COX-2 inhibitors lessen gastric adverse reactions, have similar renal impairment adverse reactions to COX-1 and COX-2 inhibitors, and increase the risk of cardiovascular events through vasoconstriction and platelet aggregation.
• COX-2 inhibitors continue to be effective at reducing inflammation and suppressing pain.

Adverse Drug Reactions

• Celecoxib can cause gastric upset, diarrhea, heartburn, nausea, and gastric ulceration, but to a lesser extent than COX-1 inhibitors.
• Renal dysfunction, cardiovascular, and cerebrovascular events remain potential adverse reactions.

Interventions

• Monitor and report gastric upset, heartburn, nausea, diarrhea, and GI bleeding in clients taking celecoxib.
• Test for and treat Helicobacter pylori infection before starting long-term NSAID therapy.
• For clients at high risk of gastric bleeding, consider a concurrent prescription of a proton pump inhibitor.
• Monitor intake/output, watch for low urine output/fluid retention, and monitor for increased BUN and creatinine levels.
• Prescribe the medication for short periods and in low doses to minimize adverse drug reactions.
• Monitor for myocardial infarction and cerebrovascular accident manifestations.
• Recommend low-dose aspirin to prevent thromboembolic events during long-term therapy.

Administration

• Administer celecoxib 2 hours before or after magnesium or aluminum-based antacids.
• Monitor for therapeutic effects throughout therapy.

Client Instructions

• Reinforce the daily use of low-dose aspirin to lower the risk of heart attack and stroke for clients on long-term NSAID therapy with a COX-2 inhibitor.
• Clients should take celecoxib with food, milk, or 8 ounces of water, and avoid alcohol, to minimize gastrointestinal effects.
• Advise clients to report persistent gastric irritation, manifestations of gastrointestinal bleeding, changes in urine output, weight gain, or fluid retention.
• Emphasize the need to report chest pain or heaviness, shortness of breath, sudden/severe headache, numbness, weakness, visual disturbances, or confusion.

Safety Alert

• The risk of gastrointestinal complications may be related to the duration of medication use, the client’s age, alcohol consumption, or smoking.
• The risk of thromboembolic events may be related to the duration of celecoxib use or a history of heart disease.
• Clients taking a COX-2 inhibitor should be aware of early manifestations of gastrointestinal bleeding (coffee-ground emesis, black tarry stools), myocardial infarction (chest heaviness, shortness of breath), and stroke (one-sided numbness/weakness, confusion).

Contraindications and Precautions

• Celecoxib is contraindicated in pregnant clients, especially during the third trimester (teratogenic effects on the ductus arteriosus).
• Contraindications also include severe hepatic or kidney impairment, age younger than 18, gastrointestinal bleeding, anemia, pain from coronary artery bypass grafting, and allergy to celecoxib, sulfa, and/or sulfonamides.
• Use celecoxib with caution in clients who have alcohol use disorder, heart failure, cardiovascular disease, hypertension, diabetes mellitus, asthma, a history of GI bleeding or peptic ulcer disease, mild or moderate liver and/or renal impairment, and cerebrovascular accident.

Interactions

• Celecoxib decreases the diuretic effects of furosemide.
• Fluconazole may increase celecoxib levels.
• Celecoxib increases the anticoagulant effects of warfarin.
• Glucocorticoids and alcohol increase the risk of bleeding.
• Celecoxib decreases the antihypertensive effects of ACE inhibitors and increases the risk of lithium carbonate toxicity.

Question Answer

• The correct answer is a: Black, tarry stools