Diclofenac

diclofenac (dye kloe' fen ak)

diclofenac potassium Cataflam, Voltaren Rapide (CAN)

diclofenac sodium Novo-Difenac (CAN), Nu-Diclo (CAN), Solaraze, Voltaren, Voltaren Ophtha (CAN), Voltaren-XR Pregnancy Category B Drug classes

Anti-inflammatory NSAID Therapeutic actions

Inhibits prostaglandin synthetase to cause antipyretic and anti-inflammatory effects; the exact mechanism is unknown. Indications

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Acute or long-term treatment of mild to moderate pain, including dysmenorrhea Rheumatoid arthritis Osteoarthritis Ankylosing spondylitis Treatment of actinic keratosis in conjunction with sun avoidance Ophthalmic: Postoperative inflammation from cataract extraction

Contraindications and cautions

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Contraindicated with allergy to NSAIDs, significant renal impairment, pregnancy, lactation. Use cautiously with impaired hearing, allergies, hepatic, cardiovascular, and GI conditions.

Available forms

Tablets—50 mg; DR tablets—25, 50, 75 mg; ER tablets—100 mg; topical gel—30 mg/g; ophthalmic solution—0.1% Dosages ADULTS Oral

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Pain, including dysmenorrhea: 50 mg tid PO; initial dose of 100 mg may help some patients (Cataflam). Osteoarthritis: 100–150 mg/day PO in divided doses (Voltaren); 50 mg bid–tid PO (Cataflam).

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Rheumatoid arthritis: 150–200 mg/day PO in divided doses (Voltaren); 50 mg bid–tid PO (Cataflam). Ankylosing spondylitis: 100–125 mg/day PO. Give as 25 mg qid, with an extra 25-mg dose hs (Voltaren); 25 mg qid PO with an additional 25 mg hs if needed (Cataflam).

Topical

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Actinic keratosis: Cover lesion with gel and smooth into skin; do not cover with dressings or cosmetics.

Ophthalmic

1 drop to affected eye qid starting 24 hr post-op for 2 wk PEDIATRIC PATIENTS

Safety and efficacy not established. Pharmacokinetics Route Oral (sodium) Oral (potassium)

Onset Varies Rapid

Peak 2–3 hr 20–120 min

Duration 12–15 hr 12–15 hr

Metabolism: Hepatic; T1/2: 1.5–2 hr Distribution: Crosses placenta; enters breast milk Excretion: Urine and feces Adverse effects

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CNS: Headache, dizziness, somnolence, insomnia, fatigue, tiredness, tinnitus, ophthamologic effects Dermatologic: Rash, pruritus, sweating, dry mucous membranes, stomatitis GI: Nausea, dyspepsia, GI pain, diarrhea, vomiting, constipation, flatulence GU: Dysuria, renal impairment Hematologic: Bleeding, platelet inhibition with higher doses Other: Peripheral edema, anaphylactoid reactions to fatal anaphylactic shock

Interactions

Drug-drug • Increased serum levels and increased risk of lithium toxicity • Increased risk of bleeding with anticoagulants; monitor patient closely Nursing considerations Assessment

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History: Renal impairment; impaired hearing; allergies; hepatic, CV, and GI conditions; lactation Physical: Skin color and lesions; orientation, reflexes, ophthalmologic and audiometric evaluation, peripheral sensation; P, edema; R, adventitious sounds; liver evaluation; CBC, clotting times, renal and liver function tests; serum electrolytes, stool guaiac

Interventions

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Administer drug with food or after meals if GI upset occurs. Arrange for periodic ophthalmologic exam during long-term therapy. Institute emergency procedures if overdose occurs (gastric lavage, induction of emesis, supportive therapy).

Teaching points

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Take drug with food or meals if GI upset occurs. Take only the prescribed dosage. These side effects may occur: Dizziness, drowsiness (avoid driving or using dangerous machinery while using this drug). Report sore throat, fever, rash, itching, weight gain, swelling in ankles or fingers, changes in vision; black, tarry stools.

Adverse effects in Italic are most common; those in Bold are life-threatening.