Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
ACULAR vs P.A.S. SODIUM
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Nonsteroidal anti-inflammatory drug (NSAID) that inhibits cyclooxygenase (COX) enzymes, reducing prostaglandin synthesis, which decreases inflammation, pain, and fever.
P. A. S. (p-aminosalicylic acid) sodium is a bacteriostatic agent that competitively inhibits the synthesis of folic acid in Mycobacterium tuberculosis by antagonizing the incorporation of p-aminobenzoic acid (PABA) into dihydrofolate. It is selective for mycobacterial folate synthase.
Treatment of postoperative inflammation in patients who have undergone cataract extraction,Relief of ocular itching due to seasonal allergic conjunctivitis
Treatment of tuberculosis (TB) in combination with other antituberculosis agents, particularly in multidrug-resistant TB (FDA-approved).,Off-label: Used as a second-line agent in atypical mycobacterial infections and in Crohn's disease (though not FDA-approved for these indications).
One drop of 0.5% ophthalmic solution into the affected eye(s) four times daily.
Oral: 4 g three times daily (total daily dose 12 g); IV: 12 g daily in 2-4 divided doses.
Terminal half-life: 1.8 hours (ketorolac tromethamine); clinical context: short half-life supports dosing every 6 hours for acute pain, but prolonged in elderly or renal impairment (↑ to 5-6 hours, thus dose reduction required).
1 hour (normal renal function); prolonged to 5-7 hours in anuria or severe renal impairment; clinical context: requires frequent dosing or renal dose adjustment
Hepatic metabolism primarily via cytochrome P450 2C9 (CYP2C9).
Primarily metabolized by hepatic acetylation via N-acetyltransferase (NAT); minor pathways include glycine conjugation and renal excretion of unchanged drug.
Renal: ~80% as unchanged drug and glucuronide conjugates; biliary/fecal: ~20%
Renal (80% as active drug and metabolites, primarily acetylated form); fecal (minor; <10%)
99% bound; primary binding protein: albumin.
50-60% (primarily to albumin)
0.11-0.25 L/kg; clinical meaning: low Vd indicates primarily confined to extracellular compartment (plasma and interstitial fluid), minimal tissue penetration.
0.5-0.6 L/kg (indicates distribution into total body water, with some tissue binding)
Ophthalmic: ~2% systemic absorption after topical instillation (due to corneal permeability and nasolacrimal drainage); oral formulation not used for Acular (ophthalmic only).
Oral: approximately 90% (well absorbed from GI tract)
No dosage adjustment required for renal impairment.
Cr Cl <50 m L/min: reduce dose by 50%; Cr Cl <10 m L/min: avoid use or reduce to 25% of normal dose.
No dosage adjustment required for hepatic impairment.
Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: avoid use.
Safety and efficacy in pediatric patients have not been established; use not recommended.
Oral: 200-300 mg/kg/day in 3-4 divided doses, maximum 12 g/day.
No specific dosage adjustment required; use same dosing as for younger adults.
Start at lower end of dosing range; monitor renal function and adjust based on Cr Cl; typical initial dose 4 g twice daily.
No FDA boxed warning.
None explicitly stated in current FDA labeling; however, caution is advised in hepatic impairment due to risk of hepatitis.
May increase bleeding time due to inhibition of platelet aggregation; use with caution in patients with known bleeding tendencies or those receiving other medications that may prolong bleeding time.,May cause corneal effects including keratitis and corneal thinning; discontinue if corneal epithelial breakdown occurs.,Use with caution in patients with prior sensitivity to aspirin, phenylacetic acid derivatives, or other NSAIDs.,May delay wound healing or exacerbate infections; avoid use in patients with active epithelial herpes simplex keratitis.
May cause severe hypersensitivity reactions (e.g., fever, rash, lymphadenopathy).,Hepatic toxicity: risk of hepatitis, especially with prolonged use; monitor liver function.,Renal impairment: dose adjustment required in severe renal disease.,Gastrointestinal intolerance: nausea, vomiting, diarrhea common.,Development of resistance if used as monotherapy.,May induce hemolytic anemia in G6PD deficiency.
Hypersensitivity to ketorolac tromethamine or any component of the formulation,History of asthma, urticaria, or allergic-type reactions after taking aspirin or other NSAIDs,Active epithelial herpes simplex keratitis,Late pregnancy (third trimester) due to risk of premature closure of ductus arteriosus
Hypersensitivity to p-aminosalicylic acid or any component.,Severe hepatic impairment.,Severe renal failure (unless dose-adjusted).,Contraindicated in patients with active peptic ulcer disease.
No known food interactions. Avoid alcohol if concomitant oral NSAIDs are used due to increased risk of gastrointestinal bleeding, but this is not specific to ophthalmic use.
Take with food, especially acidic foods (e.g., applesauce, yogurt) to improve taste and reduce gastrointestinal irritation. Avoid alkaline foods (e.g., milk, antacids) as they may decrease absorption. Avoid alcohol due to increased risk of hepatotoxicity.
Pregnancy Category C. No adequate studies in pregnant women. Ketorolac tromethamine, like other NSAIDs, may cause premature closure of the ductus arteriosus and fetal renal impairment in the third trimester. First and second trimester use should be avoided unless clearly needed. The potential benefits should be weighed against the risks.
First trimester: No evidence of teratogenicity in human studies; limited animal data show no adverse effects. Second trimester: No specific risks identified. Third trimester: No known adverse fetal effects; use only if clearly needed.
Ketorolac is excreted in human milk at low levels. The M/P ratio is not well defined. Due to potential adverse effects in nursing infants, caution is advised. Use only if clearly indicated and consider alternative agents.
Excreted into breast milk in low amounts; M/P ratio not determined. Considered compatible with breastfeeding; monitor infant for diarrhea or rash.
No specific dose adjustments are recommended for pregnancy; however, use the lowest effective dose for the shortest duration due to potential fetal risks. Physiological changes in pregnancy (increased volume of distribution, renal clearance) may alter pharmacokinetics, but no formal studies justify dose modification.
No pharmacokinetic changes requiring dose adjustment in pregnancy; use standard dosing but monitor for hepatotoxicity, which may be increased.
ACULAR (ketorolac tromethamine ophthalmic solution) is a nonsteroidal anti-inflammatory drug (NSAID) used for ocular inflammation. Avoid concomitant use with other NSAIDs or corticosteroids due to increased risk of corneal adverse events. Use with caution in patients with bleeding disorders or those on anticoagulants, as it may increase bleeding tendency. Monitor for corneal toxicity, especially in patients with compromised corneal integrity. Ensure proper storage at room temperature and discard if solution changes color or becomes cloudy.
Sodium aminosalicylate (PAS sodium) is a second-line antituberculosis agent used in multidrug-resistant TB (MDR-TB). It is bacteriostatic against Mycobacterium tuberculosis by inhibiting folate synthesis. Must be administered with other antitubercular drugs to prevent resistance. Monitor for hepatotoxicity, hypersensitivity reactions (fever, rash, eosinophilia), and gastrointestinal intolerance. Can cause hypothyroidism; monitor thyroid function. Drug interactions: may increase phenytoin levels; avoid concurrent probenecid (increases PAS levels). PAS granules should be sprinkled on soft acidic food to reduce GI upset.
Do not touch the dropper tip to any surface to avoid contamination.,Remove contact lenses before instillation and wait at least 15 minutes before reinserting.,Apply pressure to the inner corner of the eye (nasolacrimal occlusion) for 1 minute after instillation to reduce systemic absorption.,Do not use while wearing soft contact lenses, as the preservative may be absorbed.,Report any signs of corneal problems such as pain, redness, or vision changes immediately.,Use exactly as prescribed and do not share the medication with others.
Take this medication exactly as prescribed, usually twice daily with food to reduce stomach upset.,Do not skip doses; complete the full course to prevent drug resistance.,Report any signs of liver problems: yellowing of skin/eyes, dark urine, severe abdominal pain.,Notify your doctor if you develop fever, rash, or unusual tiredness.,You may need regular blood tests to monitor thyroid and liver function.,Avoid alcohol while taking this medication.,Keep all appointments for TB treatment monitoring.
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about ACULAR vs P.A.S. SODIUM, answered by our medical review team.
ACULAR is a NSAID Ophthalmic that works by Nonsteroidal anti-inflammatory drug (NSAID) that inhibits cyclooxygenase (COX) enzymes, reducing prostaglandin synthesis, which decreases inflammation, pain, and fever.. P.A.S. SODIUM is a Antitubercular Agent that works by P. A. S. (p-aminosalicylic acid) sodium is a bacteriostatic agent that competitively inhibits the synthesis of folic acid in Mycobacterium tuberculosis by antagonizing the incorporation of p-aminobenzoic acid (PABA) into dihydrofolate. It is selective for mycobacterial folate synthase.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between ACULAR and P.A.S. SODIUM depend on the specific clinical indication. These are agents from distinct pharmacological classes and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of ACULAR is: One drop of 0.5% ophthalmic solution into the affected eye(s) four times daily.. The standard adult dose of P.A.S. SODIUM is: Oral: 4 g three times daily (total daily dose 12 g); IV: 12 g daily in 2-4 divided doses.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between ACULAR and P.A.S. SODIUM in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. ACULAR is classified as Category C. Pregnancy Category C. No adequate studies in pregnant women. Ketorolac tromethamine, like other NSAIDs, may cause premature closure of the ductus arteriosus and fetal renal impairm. P.A.S. SODIUM is classified as Category C. First trimester: No evidence of teratogenicity in human studies; limited animal data show no adverse effects. Second trimester: No specific risks identified. Third trimester: No kn. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.