Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
ACTRON vs ACULAR LS
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Acetaminophen (paracetamol) is a non-opioid analgesic and antipyretic. Its mechanism is not fully understood but involves inhibition of cyclooxygenase (COX) enzymes in the central nervous system, reducing prostaglandin synthesis. It also modulates the endocannabinoid system and serotonergic pathways.
Selective COX-2 inhibitor; inhibits prostaglandin synthesis, reducing ocular inflammation and pain.
Mild to moderate pain,Fever
FDA: Treatment of postoperative inflammation in patients who have undergone cataract surgery,Off-label: Relief of ocular pain, photophobia, and inflammation associated with corneal abrasion or refractive surgery
Oral: 400 mg every 4-6 hours as needed for pain; maximum 1200 mg/day.
1 drop in the affected eye(s) four times daily
Terminal elimination half-life 2-4 hours; prolonged to 6-12 hours in elderly or renal impairment (Cr Cl <30 m L/min).
The terminal elimination half-life is approximately 1.8 hours (range 1.2–2.5 hours) following topical ocular administration. This short half-life is consistent with rapid clearance from the systemic circulation.
Primarily metabolized in the liver via glucuronidation (UGT1A1, UGT1A6, UGT1A9), sulfation (SULT1A1, SULT1A3), and oxidation (CYP2E1, CYP3A4) to form the toxic metabolite N-acetyl-p-benzoquinone imine (NAPQI), which is detoxified by glutathione.
Primarily hepatic via CYP2C9; undergoes glucuronidation and oxidation to inactive metabolites.
Renal: 90% as unchanged drug; biliary/fecal: 10% as metabolites.
Renal excretion of metabolites and unchanged drug accounts for approximately 26% of the dose. Fecal excretion accounts for approximately 74% of the dose, primarily as metabolites.
>99% bound to albumin.
Ketorolac is highly protein bound, approximately 99% bound to plasma proteins, primarily albumin.
0.1-0.2 L/kg; indicates limited extravascular distribution.
The volume of distribution is approximately 0.12 L/kg, indicating distribution primarily into extracellular fluid with limited tissue penetration.
Oral: 70-90% (first-pass metabolism minimal); IV: 100%.
Ophthalmic bioavailability is approximately 2% of the administered dose due to extensive nasolacrimal drainage and systemic absorption. Oral bioavailability of ketorolac is approximately 80-100%, but this route is not used for ophthalmic formulations.
GFR <30 m L/min: Avoid use. GFR 30-50 m L/min: Reduce dose to 50% of normal, maximum 600 mg/day.
No dosage adjustment required for renal impairment
Child-Pugh Class B: Reduce dose by 50%; maximum 600 mg/day. Child-Pugh Class C: Contraindicated.
No dosage adjustment required for hepatic impairment but use with caution in severe hepatic disease due to potential for increased systemic exposure
Children ≥12 years: 400 mg orally every 6-8 hours as needed; maximum 1200 mg/day. Children <12 years: Not recommended.
Safety and efficacy in pediatric patients below 2 years of age have not been established; for children 2 years and older, same as adult dosing
Initiate at 200 mg every 6-8 hours; maximum 600 mg/day due to increased risk of gastrointestinal bleeding and renal impairment.
No specific dose adjustment recommended; use with caution due to increased incidence of age-related ocular conditions
Acetaminophen has been associated with cases of acute liver failure, sometimes resulting in liver transplant and death. Most cases involve use of acetaminophen at doses exceeding 4000 mg per day, often involving more than one acetaminophen-containing product.
None
Hepatotoxicity: risk increased with chronic alcohol use, liver disease, or use of other acetaminophen-containing products. Avoid exceeding 4000 mg/day. Severe skin reactions: Stevens-Johnson syndrome, toxic epidermal necrolysis, acute generalized exanthematous pustulosis. Hypersensitivity reactions: anaphylaxis.
Increased risk of bleeding and bleeding-related adverse events due to platelet inhibition,May prolong bleeding time,Cross-sensitivity with aspirin and other NSAIDs,Caution in patients with prior history of corneal epithelial defects or ocular surgery,Not for intraocular injection
Severe hepatic impairment or active liver disease. Known hypersensitivity to acetaminophen or any component of the formulation.
Hypersensitivity to ketorolac tromethamine or any component of the formulation,Patients with active peptic ulcer disease, recent GI bleeding, or perforation,Patients with advanced renal disease or at risk for renal failure,Patients with known history of asthma, urticaria, or allergic-type reactions after taking aspirin or other NSAIDs
Avoid alcohol; may increase risk of GI bleeding. No specific food restrictions, but taking with food can reduce gastrointestinal irritation. Maintain adequate hydration to prevent renal impairment.
No known food interactions for ophthalmic ketorolac. However, maintain good hydration and nutrition to support corneal healing.
First trimester: Based on animal studies and limited human data, possible increased risk of cardiovascular and neural tube defects. Second/third trimester: Risk of premature closure of ductus arteriosus and oligohydramnios with prolonged use. Avoid after 30 weeks gestation.
Ketorolac tromethamine, the active ingredient in ACULAR LS, is a nonsteroidal anti-inflammatory drug (NSAID). In animal reproduction studies, administration of ketorolac during organogenesis resulted in increased embryofetal mortality, delayed ossification, and increased incidence of skeletal abnormalities at doses less than the maximum recommended human ophthalmic dose. However, systemic exposure following ocular administration is very low. NSAIDs are generally avoided during pregnancy, especially in the third trimester, due to the risk of premature closure of the ductus arteriosus and oligohydramnios. The risk is considered low for ophthalmic use but should be used only if clearly needed.
Excreted in breast milk; M/P ratio 0.15. Low oral bioavailability to infant; considered compatible with breastfeeding. Monitor infant for sedation or feeding problems.
It is not known whether ketorolac is excreted in human milk after ophthalmic administration. Systemic levels are low, and following oral administration, ketorolac is excreted in breast milk at low concentrations (M/P ratio approximately 0.37). Due to the potential for adverse effects on the nursing infant, caution should be exercised. The low systemic absorption likely poses minimal risk.
Dose adjustment not typically required; however, due to increased renal clearance and volume of distribution in pregnancy, higher doses may be needed to achieve therapeutic effect. Use lowest effective dose for shortest duration.
No dosing adjustments are necessary for ophthalmic use during pregnancy due to negligible systemic absorption. Standard dosing (1 drop in the affected eye(s) four times daily) is recommended. Systemic NSAIDs may require dose adjustment due to increased volume of distribution and renal changes, but this does not apply to topical ocular ketorolac.
ACTRON (ketorolac tromethamine) is a nonsteroidal anti-inflammatory drug (NSAID) for short-term management of moderate to severe acute pain, typically not exceeding 5 days due to risk of GI bleeding, renal impairment, and cardiovascular events. Avoid in patients with active peptic ulcer disease, bleeding diathesis, or advanced renal disease. Monitor renal function and signs of bleeding. Use lowest effective dose for shortest duration. May cause bronchospasm in aspirin-sensitive asthma.
ACULAR LS (ketorolac tromethamine ophthalmic solution 0.4%) is a nonsteroidal anti-inflammatory drug (NSAID) indicated for the reduction of ocular pain and photophobia following corneal refractive surgery. Use with caution in patients with known bleeding tendencies or those on anticoagulants due to increased risk of ocular bleeding. Avoid concurrent use with other NSAIDs or steroids to minimize corneal adverse effects. Monitor for corneal epithelial breakdown or delayed healing.
Take with food or milk to reduce stomach upset.,Do not take for more than 5 days as prescribed; longer use increases risk of serious side effects.,Avoid alcohol while taking this medication to lower risk of stomach bleeding.,Report any signs of bleeding (e.g., black stools, vomiting blood), unusual bruising, or decreased urination.,Do not take with other NSAIDs (e.g., ibuprofen, naproxen) or aspirin without consulting your doctor.,Inform your doctor about all medications, especially blood thinners (e.g., warfarin) and diuretics.,If you have asthma, be aware of potential bronchospasm; seek immediate help if you have breathing trouble.,Not recommended during pregnancy, especially in the third trimester.
Do not touch the dropper tip to any surface to avoid contamination.,Remove contact lenses before instillation and wait at least 10 minutes before reinserting.,Use only in the affected eye(s) as prescribed; do not use for longer than directed.,Temporary stinging or burning may occur upon instillation.,Report any persistent pain, redness, or visual changes to your doctor immediately.,Avoid driving or operating machinery if vision is blurred after use.
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 ACTRON vs ACULAR LS, answered by our medical review team.
ACTRON is a NSAID that works by Acetaminophen (paracetamol) is a non-opioid analgesic and antipyretic. Its mechanism is not fully understood but involves inhibition of cyclooxygenase (COX) enzymes in the central nervous system, reducing prostaglandin synthesis. It also modulates the endocannabinoid system and serotonergic pathways.. ACULAR LS is a NSAID Ophthalmic that works by Selective COX-2 inhibitor; inhibits prostaglandin synthesis, reducing ocular inflammation and pain.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between ACTRON and ACULAR LS 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 ACTRON is: Oral: 400 mg every 4-6 hours as needed for pain; maximum 1200 mg/day.. The standard adult dose of ACULAR LS is: 1 drop in the affected eye(s) four times daily. 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 ACTRON and ACULAR LS 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. ACTRON is classified as Category C. First trimester: Based on animal studies and limited human data, possible increased risk of cardiovascular and neural tube defects. Second/third trimester: Risk of premature closur. ACULAR LS is classified as Category C. Ketorolac tromethamine, the active ingredient in ACULAR LS, is a nonsteroidal anti-inflammatory drug (NSAID). In animal reproduction studies, administration of ketorolac during org. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.