DrugindexOnline^{2nd edition}

Pronouncation: (ox-uh-PRO-zin)
Class: NSAID

Trade Names:
Daypro
- Caplets 600 mg

Apo-Oxaprozin (Canada)
Rhoxal-oxaprozin (Canada)

Mechanism of Action

Pharmacology

Decreases inflammation, pain and fever, probably through inhibition of cyclooxygenase activity and prostaglandin synthesis.

Pharmacokinetics

Absorption

Bioavailability is 95%. T _max is 3 to 5 hr.

Distribution

99% is protein bound (plasma). Vd is 10 to 12.5 L.

Metabolism

Metabolized in the liver by microsomal oxidation (65%) and glucuronic acid conjugation (35%). 5% of active phenolic metabolites.

Elimination

65% glucuronide metabolites are eliminated in the urine and 35% in the feces. The t _½ is 42 to 50 hr. Clearance is 0.25 to 0.34 L/hr.

Special Populations

Renal Function Impairment

Alters binding and reduces unbound clearance and unbound volume of distribution. Dosage reduction is recommended.

Indications and Usage

Relief of symptoms of rheumatoid arthritis and osteoarthritis.

Contraindications

Hypersensitivity to aspirin, iodides, or any other NSAID.

Dosage and Administration

Adults

PO 1,200 mg once a day (max, 1,800 mg/day or 26 mg/kg, whichever is lower).

Storage/Stability

Store less than 86°F in a tight, light-resistant container.

Drug Interactions

Beta-blockers

Antihypertensive effects may be decreased.

Lithium

May increase lithium levels.

Loop diuretics

Diuretic effects may be decreased.

Methotrexate

May increase methotrexate levels.

Warfarin

May increase risk of gastric erosion and bleeding.

Laboratory Test Interactions

False-positive urine immunoassay screening tests for benzodiazepines have been reported in patients taking oxaprozin.

Adverse Reactions

Cardiovascular

Edema; blood pressure changes; worsening or precipitation of CHF.

CNS

Depression; sedation; somnolence; confusion; disturbed sleep.

Dermatologic

Rash; pruritus; erythema; photosensitivity; ecchymosis.

EENT

Visual disturbances; tinnitus.

GI

Gastric distress; peptic ulcers; occult blood loss; diarrhea; constipation; vomiting; nausea; dyspepsia; flatulence; anorexia; abdominal distress/cramps/pain; stomatitis.

Genitourinary

Difficult or painful urination; urinary frequency; decreased menstrual flow.

Hematologic

Anemia; neutropenia; thrombocytopenia; leukopenia.

Hepatic

Hepatitis.

Precautions

Pregnancy

Category C .

Lactation

Undetermined.

Children

Safety and efficacy not established.

Elderly

Increased risk of adverse reactions.

Renal Function

May need to reduce dose.

Hepatic Function

Exercise caution when administering to patients with impaired hepatic function or history of liver disease.

GI effects

Serious GI toxicity (eg, bleeding, ulceration, perforation) can occur at any time, with or without warning symptoms.

Platelet aggregation

Can inhibit platelet aggregation; use with caution in patients with intrinsic coagulation defects or those on anticoagulant therapy.

Overdosage

Symptoms

Drowsiness, nausea, heartburn, vomiting, indigestion, seizures.

Patient Information

• Instruct patient to take medication as prescribed and not to make up missed doses.
• Inform patient that analgesic effects are usually achieved after a single dose, but that it requires several days of dosing to reach the maximum effect.
• Inform patient concerning the expected therapeutic effects of the medication, which include analgesic, antipyretic and anti-inflammatory benefits.
• Instruct patient to inform the health care provider of symptom relief so that the dosage is individualized to the lowest effective dose to minimize adverse effects.
• Instruct patient to take the dose exactly as prescribed about the same time each day with a full glass of water.
• Caution patient to avoid taking other NSAIDs, aspirin, alcohol, or other otc medications unless advised to do so by the health care provider.
• Instruct patient concerning drug/drug interactions as applicable to their situation.
• Advise patient to discontinue drug and notify health care provider if any of the following occurs: persistent GI upset or headache, skin rash, itching, visual disturbances, black stools, weight gain or edema, changes in urine pattern, joint pain, fever, or blood in urine.
• Caution patient regarding the serious GI, renal, hepatic, hematologic and dermatologic adverse effects that can occur at any time, with or without warning symptoms.
• Advise patient on long-term therapy that lab tests may be required and to keep appointments.
• Caution patient to inform dentist or surgeon oxaprozin use prior to any procedure.
• Advise elderly or debilitated patients regarding their increased risk of adverse reactions.
• Caution patient regarding possibility of photosensitivity and to use protective measures until tolerance is determined.
• Advise patient that medication may cause drowsiness, and to use caution while driving or performing other tasks requiring mental alertness.