Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
ACUVAIL vs FLOWTUSS
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Ketorolac tromethamine, a nonsteroidal anti-inflammatory drug (NSAID), inhibits prostaglandin synthesis by blocking cyclooxygenase (COX-1 and COX-2) enzymes. This reduces ocular inflammation and pain.
FLOWTUSS (guaifenesin) is an expectorant that increases respiratory tract fluid secretions, reducing mucus viscosity and facilitating clearance.
Reduction of ocular pain and inflammation following cataract surgery,Treatment of ocular itching associated with seasonal allergic conjunctivitis
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 4 times daily.
10 mg orally every 4-6 hours as needed for cough; maximum 60 mg/day.
Terminal elimination half-life is approximately 46 minutes in the aqueous humor following ocular administration in humans.
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 conjugation with glucuronic acid; minor role of cytochrome P450 enzymes. Approximately 50% is excreted as parent drug and metabolites in urine.
Hepatic metabolism via oxidation and demethylation; primarily excreted renally as metabolites.
Primarily renal excretion of metabolites; less than 1% excreted unchanged. Biliary/fecal elimination accounts for <10%.
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%).
>99% bound to plasma proteins, primarily albumin.
85–90% bound to albumin and alpha-1-acid glycoprotein.
Intravenous administration in animals suggests Vd ~0.15 L/kg, indicating limited distribution; clinically, it distributes into aqueous humor after topical dosing.
1.5–2.0 L/kg; indicates extensive tissue distribution (e.g., lungs, liver).
Ocular bioavailability is dependent on formulation; systemic bioavailability after topical ocular administration is extremely low (<1%).
Oral: 75–85% (first-pass metabolism accounts for 15–25% loss).
No adjustment required. Drug is minimally systemically absorbed.
e GFR 30-60 m L/min: 5 mg every 6 hours; e GFR <30 m L/min: 5 mg every 8 hours.
No adjustment required. Drug is minimally systemically absorbed.
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 have not been established.
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 dosage adjustment is recommended; use same dose as younger adults.
Initial dose 5 mg every 6 hours; increase cautiously due to increased risk of dizziness and sedation.
No black box warning for ophthalmic use; however, systemic NSAIDs carry risk of serious cardiovascular and gastrointestinal events. Ophthalmic use rarely associated with corneal adverse events.
None.
Use with caution in patients with bleeding disorders or those on anticoagulants; may prolong bleeding time. Avoid in patients with known hypersensitivities to NSAIDs or aspirin. Can cause corneal keratopathy; discontinue if corneal epithelial breakdown occurs.
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 any component of the formulation. Active corneal epithelial defect. Patients with aspirin-sensitive asthma.
Hypersensitivity to guaifenesin or any component; concurrent use with other expectorants.
No specific food interactions; systemic absorption is minimal with ophthalmic use. Avoid concurrent use of other NSAID eye drops due to additive irritation.
No specific food interactions. Alcohol may increase CNS depressant effects (dizziness, sedation).
Acuvail (ketorolac tromethamine ophthalmic solution) is classified as FDA Pregnancy Category C. Systemic exposure after ocular administration is minimal; however, NSAIDs may cause premature closure of the ductus arteriosus and oligohydramnios in the third trimester. Use during the first and second trimesters should be limited to cases where potential benefit outweighs risk; avoid during the third trimester due to risk of fetal harm.
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.
Ketorolac is excreted in human milk following systemic administration, but ocular doses produce negligible systemic levels. The M/P ratio is not determined for ophthalmic use. Use with caution in nursing mothers, as the clinical significance is likely low due to minimal systemic absorption.
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 dosage adjustment is required for ophthalmic use during pregnancy, as systemic exposure is negligible. However, avoid use in third trimester due to risks. Pharmacokinetic changes in pregnancy do not significantly alter ocular delivery.
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).
Acuvail (ketorolac tromethamine ophthalmic solution 0.45%) is a nonsteroidal anti-inflammatory drug (NSAID) for ocular use. It is preserved with sodium chloride and not benzalkonium chloride, reducing corneal epithelial toxicity. Administer 1 drop twice daily for ocular pain and inflammation following cataract surgery. Use caution in patients with bleeding tendencies or those on anticoagulants due to risk of increased ocular bleeding. Monitor for corneal epithelial defects and keratitis, especially with prolonged use.
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.
Wash hands before each use; do not touch tip of bottle to eye or any surface to avoid contamination.,Remove contact lenses before instillation and wait at least 15 minutes before reinserting.,Contact your doctor if you experience eye pain, redness, vision changes, or if symptoms worsen.,Do not use this medication while wearing contact lenses unless directed by your doctor.,Store at room temperature, keep bottle tightly closed when not in use, and discard within 28 days of opening.
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 ACUVAIL vs FLOWTUSS, answered by our medical review team.
ACUVAIL is a NSAID Ophthalmic that works by Ketorolac tromethamine, a nonsteroidal anti-inflammatory drug (NSAID), inhibits prostaglandin synthesis by blocking cyclooxygenase (COX-1 and COX-2) enzymes. This reduces 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 ACUVAIL 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 ACUVAIL is: 1 drop in the affected eye 4 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 ACUVAIL 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. ACUVAIL is classified as Category C. Acuvail (ketorolac tromethamine ophthalmic solution) is classified as FDA Pregnancy Category C. Systemic exposure after ocular administration is minimal; however, NSAIDs may cause . 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.