Adult: Initially, 1,000 mg followed by 500 mg 8-12 hrly, depending on severity. Max: 1,500 mg daily. Some patients may require lower initial dose of 500 mg, followed by 250 mg 8-12 hrly. Elderly: Initially, 500 mg followed by 250 mg 8-12 hrly. Max: 1,500 mg daily.
Oral Osteoarthritis, Rheumatoid arthritis
Adult: 500-1,000 mg daily in 2 divided doses, adjusted according to response. Max: 1,500 mg daily.
Renal Impairment
Dose adjustment may be needed. Severe: Avoid use.
Administration
Should be taken with food.
Contraindications
Hypersensitivity to diflunisal. Patients in whom asthma, urticaria or other sensitivity reactions are precipitated by aspirin or other NSAIDS. Treatment of perioperative pain in the setting of CABG surgery; Severe renal impairment. Concomitant use w/ indometacin.
Special Precautions
Patient w/ HTN, heart failure, fluid retention, asthma, history of GI disease. Renal or hepatic impairment. Elderly. Pregnancy and lactation.
Adverse Reactions
Nausea, vomiting, dyspepsia, GI pain, bleeding or perforation; diarrhoea, constipation, flatulence, somnolence, insomnia, dizziness, tinnitus, rash, headache, fatigue, erythema multiforme, exfoliative dermatitis, Stevens-Johnson syndrome, toxic epidermal necrolysis, urticaria, pruritus, sweating, dry mucous membranes, stomatitis, photosensitivity, peptic ulcer, anorexia, eructation, gastritis, liver function abnormalities, jaundice, fever, cholestasis, hepatitis, thrombocytopenia; agranulocytosis; haemolytic anaemia, nervousness, depression, hallucinations, confusion, disorientation, vertigo; light-headedness; paraesthesias, dyspnoea, palpitation, syncope, muscle cramps, nephrotic syndrome, hearing loss, chest pain. Potentially Fatal: Serious CV thrombotic reactions, including MI and stroke; serious GI adverse events (e.g. bleeding, ulceration, and perforation of the stomach or intestines); hypersensitivity syndrome. Rarely, fulminant hepatitis, hepatic failure.
PO: C, Z (NSAIDs caused foetal ductus arteriosus premature closure, foetal renal impairment and persistent pulmonary hypertension. Avoid near term, else use lowest dose for shortest time.)
Patient Counseling Information
This drug may cause drowsiness, dizziness, blurred vision and other neurologic effects, if affected, do not drive or operate machinery.
Monitoring Parameters
Evaluate cardiac risk and potential GI bleeding. Monitor CBC, chemistry profile, BP and ophth evaluation during long-term therapy.
Overdosage
Symptoms: Drowsiness, nausea, vomiting, diarrhoea, decreased urinary output, hyperventilation, tachycardia, sweating, tinnitus, disorientation, stupor, coma and cardiorespiratory arrest. Management: Supportive and symptomatic treatment. Perform gastric lavage or emesis.
Drug Interactions
Increased risk of GI bleeding w/ warfarin. Decreased absorption w/ antacids. Decreased plasma concentration w/ aspirin. Increases plasma concentration of paracetamol. Increased risk of convulsion when used w/ quinolones. Potentially Fatal: May cause fatal GI haemorrhage w/ indometacin.
Lab Interference
May cause false increase in serum salicylate levels.
Action
Description: Mechanism of Action: Diflunisal exhibits analgesic, anti-inflammatory and antipyretic activity. Though the exact mechanism have not been clearly established, the action is associated w/ the inhibition of cyclooxygenase-1 and -2 (COX-1 and -2) enzymes, resulting in decreased formation of prostaglandin precursors. Onset: Analgesic: Approx 1 hr. Duration: 8-12 hr. Pharmacokinetics: Absorption: Well absorbed from the GI tract. Time to peak plasma concentration: Approx 2-3 hr. Distribution: Distributed into breast milk. Volume of distribution: 7.53 L. Plasma protein binding: >99%. Metabolism: Extensively metabolised in the liver to glucuronide conjugates. Excretion: Via urine (approx 90% as glucuronide conjugates) and faeces (<5%). Plasma half-life: Approx 8-12 hr.
Chemical Structure
Source: National Center for Biotechnology Information. PubChem Database. Diflunisal, CID=3059, https://pubchem.ncbi.nlm.nih.gov/compound/Diflunisal (accessed on Jan. 21, 2020)
N02BA11 - diflunisal ; Belongs to the class of salicylic acids and derivatives agents. Used to relieve pain and fever.
References
Anon. Diflunisal. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 25/05/2016.Buckingham R (ed). Diflunisal. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 25/05/2016.Diflunisal Tablet, Film-Coated (Teva Pharmaceuticals USA Inc). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 25/05/2016.McEvoy GK, Snow EK, Miller J et al (eds). Diflunisal. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 25/05/2016.
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