di·clo·fen·ac potassium (d  kl -f n  k)n. A nonsteroidal anti-inflammatory drug used to treat pain. |
diclofenac potassium,
diclofenac potassium
Cataflam, Novo-Difenac-K (CA), Novo-Difenac-SR (CA)
Pharmacologic class: Cyclooxygenase inhibitor, nonsteroidal anti-inflammatory drug (NSAID)
Therapeutic class: Nonopioid analgesic, antiarthritic
Pregnancy risk category C
FDA Boxed Warning
• Drug may increase risk of serious cardiovascular thrombotic events, myocardial infarction, and stroke. Risk may increase with duration of use. Patients with cardiovascular disease or risk factors for it may be at greater risk.
• Drug increases risk of serious GI adverse events, including bleeding, ulcers, and stomach or intestinal perforation. These events can occur at any time during use and without warning. Elderly patients are at greater risk.
• Drug is contraindicated for treatment of perioperative pain in setting of coronary artery bypass graft surgery.
Action
Unclear. Thought to block activity of cyclooxygenase, thereby inhibiting inflammatory responses of vasodilation and swelling and blocking transmission of painful stimuli.
Availability
Tablets: 50 mg, 75 mg
Tablets (delayed-release): 25 mg, 50 mg, 75 mg
Tablets (extended-release): 100 mg
⊘Indications and dosages
➣ Analgesia; dysmenorrhea
Adults: Initially, 100 mg P.O., then 50 mg t.i.d. as needed
➣ Rheumatoid arthritis
Adults: Initially, 50 mg P.O. three to four times daily. After initial response, reduce to lowest dosage that controls symptoms. Usual maintenance dosage is 25 mg t.i.d.
➣ Osteoarthritis
Adults: Initially, 50 mg P.O. two to three times daily. After initial response, reduce to lowest dosage that controls symptoms.
➣ Ankylosing spondylitis
Adults: 25 mg P.O. four to five times daily. After initial response, reduce to lowest dosage that controls symptoms.
Dosage adjustment
• Renal impairment
• Elderly patients
Off-label uses
• Post-radial keratotomy symptoms
• Dental pain
Contraindications
• Hypersensitivity to drug or its components, other NSAIDs, or aspirin
• Active GI bleeding or ulcer disease
Precautions
Use cautiously in:
• severe cardiovascular, renal, or hepatic disease; bleeding tendency
• history of porphyria or asthma
• concurrent anticoagulant use
• elderly patients
• pregnant or breastfeeding patients
• children.
Administration
• Give on empty stomach 1 hour before or after a meal.
• If drug causes GI upset, give with milk or meals.
• Make sure patient swallows extended-release form whole without chewing or crushing.
| Route | Onset | Peak | Duration |
| P.O. | 10 min | 1 hr | 8 hr |
| P.O. (delayed) | 30 min | 2-3 hr | 8 hr |
| P.O. (extended) | Unknown | 5-6 hr | Unknown |
Adverse reactions
CNS: dizziness, drowsiness, headache
CV: hypertension
EENT: tinnitus
GI: diarrhea, abdominal pain, dyspepsia, heartburn, peptic ulcer, GI bleeding, GI perforation
GU: dysuria, frequent urination, hematuria, proteinuria, nephritis, acute renal failure
Hematologic: prolonged bleeding time
Hepatic: hepatotoxicity
Skin: eczema, photosensitivity, rash, contact dermatitis, dry skin, exfoliation
Other: allergic reactions (including edema), anaphylaxis
Interactions
Drug-drug. Anticoagulants, antiplatelet agents, cephalosporins, plicamycin, thrombolytics: increased risk of bleeding
Antihypertensives, diuretics: decreased efficacy of these drugs
Antineoplastics: increased risk of hematologic adverse reactions
Colchicine, corticosteroids, other NSAIDs: additive adverse GI effects
Cyclosporine, probenecid: increased risk of diclofenac toxicity
Digoxin, lithium, methotrexate, phenytoin, theophylline: increased levels of these drugs, greater risk of toxicity
Potassium-sparing diuretics: increased risk of hyperkalemia
Drug-diagnostic tests. Alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, blood urea nitrogen, creatinine, electrolytes, lactate dehydrogenase, urine uric acid: increased values
Bleeding time: prolonged
Hematocrit, hemoglobin, platelets, serum uric acid, urine electrolytes, white blood cells: decreased values
Drug-herbs. Anise, arnica, chamomile, clove, dong quai, fenugreek, feverfew, garlic, ginger, ginkgo, ginseng, and others: increased risk of bleeding
Drug-behaviors. Alcohol use: increased risk of adverse GI effects
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 potassium-sparing diuretics.
• 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 drug, to minimize esophageal irritation.
• Instruct patient to stop taking drug and contact prescriber promptly if he experiences ringing or buzzing in ears, dizziness, GI discomfort, or bleeding.
• Caution patient not to take over-the-counter analgesics during diclofenac therapy.
• 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.
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