Non–steroidal anti-inflammatory drugs (NSAIDS)-Phenylacetic acid

Name of Phenylacetic acid non-steroidal anti-inflammatory drugs (NSAIDS)

1. Diclofenac

1.Diclofenac

Mechanism of Action

Blocks the activity of cyclooxygenase, the enzyme needed to synthesize prostaglandins, which mediate inflammatory response and cause local pain, swelling, and vasodilation. By blocking cyclooxygenase and inhibiting prostaglandins, diclofenac reduces inflammatory symptoms. This mechanism also relieves pain because prostaglandins promote pain transmission from periphery to spinal cord.

Pharmacokinetics

• Bioavailability: 55%
• Peak plasma time: 1 hr
• Protein bound: >99%
• Half-life: ~2 hr
• Excretion: Urine (~65%); bile (~35%)

Administration

• Give on empty stomach 1 hour before or after a meal.
• If drug causes GI upset, give with milk or meals. Mix and give oral powder with 30 to 60 ml of water only.
• Make sure patient swallows extended release and delayed-release forms whole without chewing or crushing.
• Know that oral powder isn’t indicated for prophylactic migraine therapy or cluster headaches.
•   Know that oral powder formulation isn’t interchangeable with other oral forms.
• Don’t apply patch to damaged or nonintact skin.
• Avoid contact of patch with eyes and mucosa. If eye contact occurs, immediately wash eyes with water or saline solution

Contraindications

• Hypersensitivity to drug or its components, other NSAIDs, or aspirin
• Active GI bleeding or ulcer disease
• Aspirin-sensitive asthma, urticaria
• Use as perioperative analgesia in coronary artery bypass graft surgery
• Use on nonintact or damaged skin (patch)

Precautions:

• Severe cardiovascular (including patients taking diuretics or ACE inhibitors, patients with fluid retention, hypertension, or congestive heart failure), renal, or hepatic disease; bleeding tendency; dehydration
• Advanced renal disease (not recommended)
• History of porphyria or preexisting asthma
• Concurrent methotrexate or anticoagulant use; concurrent use of drugs known to be potentially hepatotoxic (such as acetaminophen, anti-infectives, or antiepileptics)
• Concurrent use of aspirin (not recommended)
• Concurrent use with oral NSAIDs (avoid use)
• Elderly patients
• Pregnant or breastfeeding patients
• Children (safety and efficacy not established)

Adverse reactions

• CNS: dizziness, drowsiness, headache, paresthesia
• CV: hypertension, thrombosis
• EENT: tinnitus
• GI: dyspepsia, diarrhea, abdominal pain, dyspepsia, heartburn, peptic ulcer, GI bleeding, GI perforation
• GU: dysuria, frequent urination, hematuria, proteinuria, nephritis, acute renal failure
• Hepatic: liver failure
• Hematologic: prolonged bleeding time
• Hepatic: hepatotoxicity
• Skin: eczema, photosensitivity, rash, contact dermatitis, dry skin, exfoliation; application-site reactions, including pruritus, dermatitis, burning (with patch); exfoliative dermatitis, Stevens-Johnson syndrome, toxic epidermal necrolysis Other: dysgeusia, pain and redness allergic reactions (including edema), anaphylaxis

Patient monitoring

• Monitor hepatic and renal function.
• Observe for and report signs and symptoms of bleeding.
• Assess for hypertension.
• Monitor sodium and potassium levels in patients receiving potassiumsparing diuretics.
• Discontinue drug if rash or other signs of local skin reaction occur.
• Discontinue drug immediately if abnormal liver test values persist or worsen.
• Weigh patient to detect fluid retention. Report gain of more than 2 lb in 24 hours

Patient teaching

• Instruct patient to take drug on empty stomach 1 hour before or after a meal.
• Advise patient not to lie down for 15 to 30 minutes after taking oral drug, to minimize esophageal irritation.
• Instruct patient to mix oral powder in 1 to 2 ounces of water only before taking.
• Tell patient to measure proper amount of gel using measuring dosing card supplied and to gently massage gel into skin of entire affected foot, knee, or ankle.
• Instruct patient to apply 10 drops of topical solution to clean, dry skin and to spread evenly around front, back, and sides of knee; then repeat this procedure until 40 drops have been applied and knee is completely covered with solution.
• Instruct patient not to apply gel, patch, or topical solution to open wounds and to avoid contact with eyes and mucous membranes.
• Advise patient to avoid exposing treated sites to bath water and sunlight, external heat, occlusive dressings or clothing, sunscreens, cosmetics, lotions, moisturizers, insect repellants, or other topical drugs.
• Instruct patient to wash hands thoroughly after applying topical solution, patch, or gel except when gel is applied to the hand. If gel is applied to a hand, advise patient to avoid washing treated hands for at least 1 hour after application.
• Tell patient to discard used patches out of the reach of children and pets.
• Instruct patient to stop drug and immediately report wheezing and signs or symptoms of hypersensitivity reactions (rash, swelling of face or throat, shortness of breath) or liver impairment (unusual tiredness, weakness, nausea, yellowing of skin or eyes, tenderness on right upper side of abdomen, flulike symptoms).
• Instruct patient to stop taking drug and contact prescriber promptly if he experiences ringing or buzzing in ears, dizziness, GI discomfort, or bleeding.
• Inform patient that drug may cause serious CV side effects and to immediately report such signs and symptoms as unexplained weight gain, chest pain, shortness of breath, weakness, or slurred speech.
• Caution patient not to take over-thecounter analgesics during diclofenac therapy.
• Advise female patient to avoid pregnancy while taking this drug.
• Advise breastfeeding patient that she should decide whether to discontinue breastfeeding or discontinue drug, taking into account importance of drug for her treatment.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, herbs, and behaviors mentioned above

Nursing Considerations

• Use diclofenac with extreme caution and for shortest possible time in patients with a history of GI bleeding or ulcer disease because NSAIDs increase risk of GI bleeding and ulceration.
• Don’t substitute one form of oral diclofenac for another. Different formulations aren’t bioequivalent.
• Be aware that serious GI tract ulceration and bleeding, as well as perforation of stomach or intestine, can occur without warning or symptoms. Elderly patients are at greater risk. Monitor patient for signs of GI irritation and ulceration, especially if patient has a predisposing condition (such as a history of GI bleeding); takes an oral corticosteroid, anticoagulant, or NSAID (long-term); smokes; is an alcoholic; is over age 60; has poor general health; or tests positive for Helicobacter pylori. To minimize risk, give diclofenac with food. If patient develops GI distress, withhold drug and notify prescriber immediately.
• Use diclofenac cautiously in patients with hypertension, and monitor blood pressure closely; drug can cause or worsen hypertension.
• Assess patient for hypotension. If patient takes a potassium-sparing diuretic, check for elevated serum potassium level.
• Report signs of bleeding, such as bleeding gums, bloody or cloudy urine, ecchymoses, melena, and petechiae.
• Monitor BUN and serum creatinine levels in elderly patients, patients taking ACE inhibitors or diuretics, and patients with heart failure or impaired renal or hepatic function. These patients may have an increased risk of renal failure.
• Assess patient’s skin routinely for rash or other signs of hypersensitivity reaction; drug may cause serious skin reactions without warning. At first sign of reaction, stop drug and notify prescriber.
• Because severe hepatic reactions may occur during diclofenac therapy, monitor liver function test results and serum uric acid level. Liver enzyme elevations usually occur within 2 months of starting drug and should be reported promptly because dosage may need adjustment. Also monitor patient for evidence of hepatic dysfunction (diarrhea, fatigue, flulike symptoms, jaundice, lethargy, nausea, pruritus, right upper quadrant tenderness).
• Report weight gain of more than 1 kg (2 lb) in 24 hours because it suggests fluid retention

REFERENCES

1. Robert Kizior, Keith Hodgson, Saunders Nursing Drug handbook,1st edition 2024, Elsevier Publications. ISBN-9780443116070
2. McGraw Hill- Drug Handbook, Seventh Edition, 2013, McGraw Hill Education Publications,9780071799430.
3. April Hazard, Cynthia Sanoski, Davi’s Drug Guide for Nurses -Sixteenth Edition 2019, FA Davis Company Publications,9780803669451.
4. Jones and Bartlet, Pharmacology for Nurses, Second Edition, 2020, Jones and Bartlet Learning Publications, ISBN 9781284141986.
5. Nursebro.com, Search – Nursebro

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