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

·        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

·        Contraindicated with allergy to NSAIDs, significant renal impairment, pregnancy, lactation.

·        Use cautiously with impaired hearing, allergies, hepatic, CV, GI conditions, and in elderly patients.

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

·        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).

·        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

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

Ophthalmic

1 drop to affected eye qid starting 24 hr after surgery for 2 wk

PEDIATRIC PATIENTS

Safety and efficacy not established.

Pharmacokinetics

Route	Onset	Peak	Duration
Oral (sodium)	Varies	2–3 hr	12–15 hr
Oral (potassium)	Rapid	20–120 min	12–15 hr

Metabolism: Hepatic; T_1/2: 1.5–2 hr

Distribution: Crosses placenta; enters breast milk

Excretion: Feces, urine

Adverse effects

·        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

·        History: Renal impairment; impaired hearing; allergies; hepatic, CV, and GI conditions; lactation, pregnancy

·        Physical: Skin color and lesions; orientation, reflexes, ophthalmologic and audiometric evaluation, peripheral sensation; P, edema; R, adventitious sounds; liver evaluation; CBC, clotting times, LFTs, renal function tests; serum electrolytes, stool guaiac

Interventions

·        Administer drug with food or after meals if GI upset occurs.

·        Arrange for periodic ophthalmologic examination during long-term therapy.

·        WARNING: Institute emergency procedures if overdose occurs (gastric lavage, induction of emesis, supportive therapy).

Teaching points

·        Take drug with food or meals if GI upset occurs.

·        Take only the prescribed dosage.

·        You may experience these side effects: 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.