Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
ACULAR PRESERVATIVE FREE vs ALAWAY
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Ketorolac tromethamine is a nonsteroidal anti-inflammatory drug (NSAID) that inhibits cyclooxygenase (COX-1 and COX-2) enzymes, thereby reducing prostaglandin synthesis. It produces anti-inflammatory and analgesic effects.
ALAWAY (cetirizine ophthalmic solution) is a selective histamine H1-receptor antagonist that inhibits histamine release from mast cells, reducing ocular itching and allergic conjunctivitis symptoms.
FDA-approved: Treatment of ocular inflammation and pain following cataract surgery and corneal refractive surgery.,Off-label: Relief of seasonal allergic conjunctivitis symptoms, management of cystoid macular edema, and treatment of postoperative inflammation in other ocular procedures.
Treatment of ocular itching associated with allergic conjunctivitis
1 drop into affected eye(s) four times daily (every 6 hours). Instill into conjunctival sac. Shake well before use.
2 doses (each dose = 2 sprays) per nostril, repeated every 12 hours as needed. Each spray delivers 50 mg of sodium cromoglicate. Route: intranasal. Maximum: 2 doses per nostril per day.
Terminal elimination half-life is approximately 5-6 hours in adults, but can be prolonged in elderly patients (up to 8-9 hours) and in patients with renal impairment (up to 13-19 hours).
Terminal elimination half-life of 3-4 hours in healthy adults; extended to 10-15 hours in severe renal impairment (Cr Cl <30 m L/min). Clinical context: Twice-daily dosing is standard; dose adjustment required in renal insufficiency.
Ketorolac undergoes hepatic metabolism via hydroxylation and conjugation (glucuronidation) to inactive metabolites. It is primarily metabolized by CYP2D6 and CYP3A4 isoenzymes, with renal excretion of metabolites and unchanged drug.
Not extensively metabolized in the eye; systemic metabolism by hepatic CYP450 enzymes is minimal due to low systemic absorption.
Primarily renal excretion of metabolites and unchanged drug; approximately 80% of a dose is excreted in urine as ketorolac and its hydroxy metabolites, with about 6% excreted in feces.
Primarily renal excretion (80-90% unchanged drug) via glomerular filtration and active tubular secretion; 10-20% fecal excretion. Minimal biliary elimination.
99% bound to plasma proteins, primarily albumin.
Approximately 65-75% bound primarily to albumin; minor binding to alpha-1-acid glycoprotein.
0.15-0.25 L/kg after oral administration; for ophthalmic use, systemic absorption is minimal, so Vd is not clinically meaningful.
Vd: 1.0-1.5 L/kg, indicating extensive distribution into total body water and tissues; high penetration into ocular tissues and respiratory mucosa.
Ophthalmic administration: Systemic bioavailability is approximately 0.5-1% after ocular instillation due to low corneal penetration and rapid clearance; oral bioavailability is 100%.
Oral: ~50% due to first-pass metabolism (CYP3A4 and P-glycoprotein). Ophthalmic solution: negligible systemic absorption (<0.5% of topical dose). Intravenous: 100%.
No dosage adjustment required for renal impairment. Drug is minimally absorbed systemically.
No dosage adjustment required. Sodium cromoglicate is primarily excreted unchanged in urine, but no specific GFR-based adjustments are recommended due to wide safety margin.
No dosage adjustment required for hepatic impairment. Drug is minimally absorbed systemically.
No dosage adjustment required. Sodium cromoglicate is minimally metabolized and undergoes biliary excretion; however, no specific Child-Pugh based modifications are established.
Children ≥3 years: 1 drop into affected eye(s) four times daily. Safety and efficacy in children <3 years not established.
Children 2-5 years: 1 spray per nostril every 6-8 hours as needed. Children 6 years and older: same as adult (2 sprays per nostril every 12 hours). Maximum 2 doses per nostril per day in all age groups. Weight-based dosing not established.
No specific dosage adjustment required. Use same dose as adults; monitor for tolerability.
No specific dose adjustment required; use same adult dose. Caution in elderly with renal impairment due to potential accumulation, though clinical significance is minimal.
NSAIDs may increase the risk of serious cardiovascular events (e.g., myocardial infarction, stroke) and gastrointestinal events (e.g., bleeding, ulceration, perforation). However, due to low systemic absorption with ophthalmic use, this boxed warning is less clinically relevant but still applies.
None
Use with caution in patients with compromised ocular surface, history of herpes simplex keratitis, bleeding tendencies, or those on anticoagulants. Prolonged use may delay wound healing. Monitor for signs of corneal epithelial breakdown or infection.
For topical ophthalmic use only,Do not inject,Contact lens wearers should remove lenses before instillation and wait at least 10 minutes before reinserting,May cause temporary blurred vision,Avoid touching dropper tip to any surface to prevent contamination
Hypersensitivity to ketorolac or any component of the formulation; patients with active ocular infection or advanced dry eye; history of asthma, urticaria, or allergic-type reactions to aspirin or other NSAIDs.
Hypersensitivity to cetirizine or any component of the formulation
No known food interactions. No dietary restrictions required.
No specific food interactions with Alaway ophthalmic solution. Take as directed, regardless of meals. Avoid rubbing eyes after application.
FDA Pregnancy Category C. No adequate studies in pregnant women. In animal studies, ketorolac tromethamine (active ingredient) was not teratogenic in rats or rabbits at doses up to 1.5-3 times the human exposure. However, because NSAIDs can cause premature closure of the ductus arteriosus and oligohydramnios in the third trimester, use is contraindicated after 30 weeks gestation. In first and second trimesters, use only if potential benefit justifies potential fetal risk.
ALAWAY (azelastine) is classified as FDA Pregnancy Category C. In animal studies, azelastine administered orally during organogenesis produced fetal malformations (cleft palate, skeletal abnormalities) at maternally toxic doses (≥ 30 mg/kg/day in rats, 68 times the maximum recommended human intranasal dose). There are no adequate and well-controlled studies in pregnant women. First trimester: Risk cannot be ruled out; use only if potential benefit justifies potential risk to fetus. Second and third trimesters: Limited data; avoid use unless necessary due to lack of safety evidence.
Ketorolac is excreted in human milk following oral administration. After a single intramuscular dose of 10 mg, the milk-to-plasma (M/P) ratio was 0.037. Low levels are expected in breastmilk; however, due to potential adverse effects of NSAIDs on neonates, caution is advised. Use is generally avoided in nursing mothers, especially with premature infants or those with thrombocytopenia or renal impairment.
Azelastine is excreted in human breast milk; the milk-to-plasma ratio (M/P) is unknown. In a study of intranasal azelastine (2 sprays per nostril twice daily), the estimated daily infant dose via breast milk is 0.7% of the maternal dose, which is considered low. However, due to the potential for adverse effects in nursing infants (e.g., somnolence, irritability), caution is advised. Use only if clearly needed and benefit outweighs risk. Consider alternative therapies with more safety data.
No specific pharmacokinetic studies in pregnancy. Dosing should be at the lowest effective dose for the shortest duration. Avoid use after 30 weeks gestation. No adjustment for first or second trimester unless renal function changes.
No specific dose adjustments are recommended for pregnancy. However, pharmacokinetic changes during pregnancy (e.g., increased plasma volume, altered hepatic metabolism) may reduce azelastine systemic exposure; the clinical significance is unknown. Use the lowest effective dose for the shortest duration. Maximum recommended intranasal dose: 2 sprays per nostril twice daily (total 548 mcg/day). Avoid exceeding this dose.
ACULAR (ketorolac tromethamine ophthalmic solution) is an NSAID for ocular use. Preservative-free formulation is indicated for single-use to avoid corneal toxicity. Apply with caution in patients with bleeding disorders or those on anticoagulants due to risk of ocular bleeding. Prolonged use may delay corneal healing. Monitor for signs of keratitis or conjunctival hyperemia.
Alaway (ketotifen fumarate ophthalmic solution) is used for prevention of itching associated with allergic conjunctivitis. It is a mast cell stabilizer with antihistamine properties. Onset of action occurs within minutes, but may require several days of use for full effect. Advise patients to avoid wearing contact lenses if eyes are red. Remove contacts before instillation and wait at least 10 minutes before reinserting.
Use exactly as prescribed; do not touch the dropper tip to any surface to avoid contamination.,Each single-use vial is for one dose only; discard after use to prevent infection.,Remove contact lenses before instillation and wait 10 minutes before reinserting.,Do not drive or operate machinery if vision is blurry after application.,Report eye pain, increased redness, or vision changes to your doctor immediately.
Do not touch the dropper tip to any surface to avoid contamination.,Remove contact lenses before using this medication; wait at least 10 minutes after using drops before reinserting.,Use as directed, typically one drop in each affected eye twice daily, with at least 6-8 hours between doses.,Do not use while wearing contact lenses if eyes are red or irritated.,Temporary burning or stinging may occur upon instillation.
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 PRESERVATIVE FREE vs ALAWAY, answered by our medical review team.
ACULAR PRESERVATIVE FREE is a NSAID Ophthalmic that works by Ketorolac tromethamine is a nonsteroidal anti-inflammatory drug (NSAID) that inhibits cyclooxygenase (COX-1 and COX-2) enzymes, thereby reducing prostaglandin synthesis. It produces anti-inflammatory and analgesic effects.. ALAWAY is a Ophthalmic Antihistamine that works by ALAWAY (cetirizine ophthalmic solution) is a selective histamine H1-receptor antagonist that inhibits histamine release from mast cells, reducing ocular itching and allergic conjunctivitis symptoms.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between ACULAR PRESERVATIVE FREE and ALAWAY 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 PRESERVATIVE FREE is: 1 drop into affected eye(s) four times daily (every 6 hours). Instill into conjunctival sac. Shake well before use.. The standard adult dose of ALAWAY is: 2 doses (each dose = 2 sprays) per nostril, repeated every 12 hours as needed. Each spray delivers 50 mg of sodium cromoglicate. Route: intranasal. Maximum: 2 doses per nostril per 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 PRESERVATIVE FREE and ALAWAY 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 PRESERVATIVE FREE is classified as Category C. FDA Pregnancy Category C. No adequate studies in pregnant women. In animal studies, ketorolac tromethamine (active ingredient) was not teratogenic in rats or rabbits at doses up to. ALAWAY is classified as Category C. ALAWAY (azelastine) is classified as FDA Pregnancy Category C. In animal studies, azelastine administered orally during organogenesis produced fetal malformations (cleft palate, sk. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.