Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
ACULAR LS vs FLOWTUSS
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Selective COX-2 inhibitor; inhibits prostaglandin synthesis, reducing ocular inflammation and pain.
FLOWTUSS (guaifenesin) is an expectorant that increases respiratory tract fluid secretions, reducing mucus viscosity and facilitating clearance.
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
Relief of productive cough associated with respiratory tract infections,Chronic obstructive pulmonary disease (COPD) exacerbations,Cystic fibrosis (off-label)
1 drop in the affected eye(s) four times daily
10 mg orally every 4-6 hours as needed for cough; maximum 60 mg/day.
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.
Terminal elimination half-life is 4–6 hours in adults with normal renal function; prolonged to 8–12 hours in moderate renal impairment (Cr Cl 30–50 m L/min).
Primarily hepatic via CYP2C9; undergoes glucuronidation and oxidation to inactive metabolites.
Hepatic metabolism via oxidation and demethylation; primarily excreted renally 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.
Renal elimination of unchanged drug accounts for 60–70%; hepatic metabolism (30–40%) with fecal excretion of metabolites via bile (20–25%) and urine (10–15%).
Ketorolac is highly protein bound, approximately 99% bound to plasma proteins, primarily albumin.
85–90% bound to albumin and alpha-1-acid glycoprotein.
The volume of distribution is approximately 0.12 L/kg, indicating distribution primarily into extracellular fluid with limited tissue penetration.
1.5–2.0 L/kg; indicates extensive tissue distribution (e.g., lungs, liver).
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.
Oral: 75–85% (first-pass metabolism accounts for 15–25% loss).
No dosage adjustment required for renal impairment
e GFR 30-60 m L/min: 5 mg every 6 hours; e GFR <30 m L/min: 5 mg every 8 hours.
No dosage adjustment required for hepatic impairment but use with caution in severe hepatic disease due to potential for increased systemic exposure
Child-Pugh Class B: 5 mg every 6 hours; Child-Pugh Class C: 2.5 mg every 8 hours.
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
Children 2-6 years: 2.5 mg orally every 6 hours; 6-12 years: 5 mg orally every 6 hours; >12 years: same as adult.
No specific dose adjustment recommended; use with caution due to increased incidence of age-related ocular conditions
Initial dose 5 mg every 6 hours; increase cautiously due to increased risk of dizziness and sedation.
None
None.
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
Avoid use with persistent or chronic cough (e.g., smoking, asthma, COPD) unless directed by a physician. Use caution in patients with renal impairment.
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
Hypersensitivity to guaifenesin or any component; concurrent use with other expectorants.
No known food interactions for ophthalmic ketorolac. However, maintain good hydration and nutrition to support corneal healing.
No specific food interactions. Alcohol may increase CNS depressant effects (dizziness, sedation).
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.
FLOWTUSS contains guaifenesin and dextromethorphan. Guaifenesin is FDA pregnancy category C; animal studies show fetal abnormalities at high doses, but human data insufficient. Dextromethorphan is category C; limited human studies show no clear teratogenic risk, but high doses may cause fetal toxicity. Avoid in first trimester; use only if benefit outweighs risk in second and third trimesters.
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.
Guaifenesin and dextromethorphan are excreted in breast milk in low amounts. M/P ratio not established for either. Use with caution; monitor infant for sedation or respiratory depression.
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.
No standard dose adjustment recommended during pregnancy. Use lowest effective dose for shortest duration. Consider pharmacokinetic changes in pregnancy (increased clearance of dextromethorphan may require higher doses for efficacy, but safety limits apply).
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.
FLOWTUSS (guaifenesin) is an expectorant that increases respiratory tract fluid secretion, reducing mucus viscosity. Onset of action is 30-60 minutes. Maximum effect requires adequate hydration (8-10 glasses of water daily). Not recommended for chronic cough due to smoking, asthma, or emphysema. Avoid use in patients with persistent cough lasting >1 week or accompanied by fever, rash, or headache. May cause dizziness; caution when driving.
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.
Drink plenty of water to help loosen mucus.,Do not take more than 6 doses in 24 hours.,Discontinue and consult doctor if cough persists >7 days or if fever, rash, or headache develop.,Avoid alcohol; may increase dizziness.,Do not use for chronic cough from smoking or asthma without medical advice.
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 LS vs FLOWTUSS, answered by our medical review team.
ACULAR LS is a NSAID Ophthalmic that works by Selective COX-2 inhibitor; inhibits prostaglandin synthesis, reducing ocular inflammation and pain.. FLOWTUSS is a Expectorant that works by FLOWTUSS (guaifenesin) is an expectorant that increases respiratory tract fluid secretions, reducing mucus viscosity and facilitating clearance.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between ACULAR LS and FLOWTUSS 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 LS is: 1 drop in the affected eye(s) four times daily. The standard adult dose of FLOWTUSS is: 10 mg orally every 4-6 hours as needed for cough; maximum 60 mg/day.. 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 LS and FLOWTUSS 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 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. FLOWTUSS is classified as Category C. FLOWTUSS contains guaifenesin and dextromethorphan. Guaifenesin is FDA pregnancy category C; animal studies show fetal abnormalities at high doses, but human data insufficient. Dex. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.