Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
ACULAR vs DIMETANE-DX
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.
Dimetane-DX contains brompheniramine (first-generation antihistamine) and dextromethorphan (NMDA receptor antagonist and sigma-1 agonist). Brompheniramine antagonizes histamine at H1 receptors, reducing allergic symptoms; dextromethorphan suppresses cough by acting on the cough center in the medulla oblongata via NMDA receptor antagonism and sigma-1 receptor activation.
Treatment of postoperative inflammation in patients who have undergone cataract extraction,Relief of ocular itching due to seasonal allergic conjunctivitis
Relief of cough and upper respiratory symptoms associated with allergy or common cold (FDA-approved OTC use)
One drop of 0.5% ophthalmic solution into the affected eye(s) four times daily.
Adults and children ≥12 years: One tablet (brompheniramine 4 mg, dextromethorphan 10 mg, phenylephrine 10 mg) orally every 4 hours as needed, not to exceed 4 doses in 24 hours.
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).
Brompheniramine: 25-30 hours; guaifenesin: 1 hour; dextromethorphan: 2-4 hours (CYP2D6 extensive metabolizers) or 20-40 hours (poor metabolizers).
Hepatic metabolism primarily via cytochrome P450 2C9 (CYP2C9).
Brompheniramine is hepatically metabolized via CYP450 enzymes (primarily CYP2D6). Dextromethorphan is extensively metabolized by CYP2D6 to dextrorphan (active metabolite).
Renal: ~80% as unchanged drug and glucuronide conjugates; biliary/fecal: ~20%
Renal: 50-70% (brompheniramine) as metabolites and unchanged drug; guaifenesin metabolites primarily renal; dextromethorphan and metabolites renal. Biliary/fecal: minor.
99% bound; primary binding protein: albumin.
Brompheniramine: 50-60% to albumin; guaifenesin: <5%; dextromethorphan: 60-70% 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.
Brompheniramine: 1.5-2.0 L/kg; guaifenesin: 0.5-1.0 L/kg; dextromethorphan: 5-10 L/kg.
Ophthalmic: ~2% systemic absorption after topical instillation (due to corneal permeability and nasolacrimal drainage); oral formulation not used for Acular (ophthalmic only).
Oral: brompheniramine 50-70%, guaifenesin 70-90%, dextromethorphan 40-60% (first-pass metabolism).
No dosage adjustment required for renal impairment.
e GFR 30–59 m L/min: Administer with caution and reduce frequency to every 6 hours. e GFR <30 m L/min: Avoid use due to risk of accumulation of dextromethorphan and phenylephrine.
No dosage adjustment required for hepatic impairment.
Child-Pugh Class A: No adjustment. Child-Pugh Class B: Reduce dosing interval to every 8 hours; use with caution. Child-Pugh Class C: Contraindicated due to extensive first-pass metabolism.
Safety and efficacy in pediatric patients have not been established; use not recommended.
Children 6–11 years: 5 m L (half the adult dose) of liquid formulation (brompheniramine 2 mg, dextromethorphan 5 mg, phenylephrine 5 mg per 5 m L) orally every 4 hours, max 4 doses/day. Children 2–5 years: 2.5 m L orally every 4 hours, max 4 doses/day. Children <2 years: Contraindicated.
No specific dosage adjustment required; use same dosing as for younger adults.
Age ≥65 years: Initiate at half the adult dose (e.g., one tablet every 8 hours) due to increased anticholinergic effects and risk of urinary retention, constipation, and dizziness. Avoid in frail elderly or those with cognitive impairment.
No FDA boxed warning.
None.
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.
Do not use with MAOIs or for 2 weeks after stopping MAOIs due to risk of serotonin syndrome (dextromethorphan).,Avoid use in patients with asthma, chronic bronchitis, emphysema, or persistent cough (may suppress cough reflex).,Use with caution in patients with glaucoma, prostatic hyperplasia, urinary retention, or hypertension (brompheniramine anticholinergic effects).,CNS depression risk: may cause drowsiness; avoid alcohol or other sedatives.
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
Concurrent MAOI therapy or within 14 days,Neonates or premature infants (brompheniramine),Breastfeeding (may suppress lactation; dextromethorphan safety not established),Severe hypertension or coronary artery disease (brompheniramine may increase heart rate)
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.
Avoid concurrent use of tyramine-rich foods (e.g., aged cheeses, cured meats, soy sauce, fermented foods) due to risk of hypertensive crisis with sympathomimetic (phenylephrine). Grapefruit juice may increase dextromethorphan levels; avoid large amounts.
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.
Dimetane-DX contains brompheniramine (antihistamine) and dextromethorphan (antitussive). First trimester: Limited human data; animal studies show no teratogenicity at therapeutic doses. Second and third trimesters: Avoid due to risk of neonatal respiratory depression, withdrawal symptoms, and anticholinergic effects. Dextromethorphan: No clear teratogenic risk, but avoid use. Overall: Contraindicated in pregnancy unless benefit outweighs risk.
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.
Brompheniramine may suppress lactation and cause irritability in infants. Dextromethorphan is excreted in breast milk in small amounts (M/P ratio not well defined). Use with caution; consider alternative therapy.
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 specific dose adjustments are recommended for Dimetane-DX in pregnancy due to limited data. However, increased plasma volume and altered drug metabolism may reduce efficacy; clinicians should consider lowest effective dose and shortest duration. Avoid near delivery.
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.
DIMETANE-DX combines brompheniramine (first-generation antihistamine), phenylephrine (decongestant), and dextromethorphan (antitussive). Avoid in hypertension, MAOI use, or asthma. Monitor for CNS depression and anticholinergic effects.
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.
Do not drive or operate machinery until you know how this medication affects you; it may cause drowsiness or dizziness.,Avoid alcohol and other sedatives; they increase sedation and CNS depression.,Do not exceed recommended dosage or use for more than 7 days for cough.,Stop use and consult a doctor if symptoms persist or worsen, or if you develop fever, rash, or persistent headache.,Inform your healthcare provider if you have high blood pressure, heart disease, glaucoma, or urinary retention.
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 DIMETANE-DX, 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.. DIMETANE-DX is a Antitussive Combination that works by Dimetane-DX contains brompheniramine (first-generation antihistamine) and dextromethorphan (NMDA receptor antagonist and sigma-1 agonist). Brompheniramine antagonizes histamine at H1 receptors, reducing allergic symptoms; dextromethorphan suppresses cough by acting on the cough center in the medulla oblongata via NMDA receptor antagonism and sigma-1 receptor activation.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between ACULAR and DIMETANE-DX 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 DIMETANE-DX is: Adults and children ≥12 years: One tablet (brompheniramine 4 mg, dextromethorphan 10 mg, phenylephrine 10 mg) orally every 4 hours as needed, not to exceed 4 doses in 24 hours.. 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 DIMETANE-DX 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. DIMETANE-DX is classified as Category C. Dimetane-DX contains brompheniramine (antihistamine) and dextromethorphan (antitussive). First trimester: Limited human data; animal studies show no teratogenicity at therapeutic d. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.