APHTHASOL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for APHTHASOL (APHTHASOL).
Aphthasol (amlexanox) is an anti-inflammatory agent that inhibits the formation and release of inflammatory mediators such as histamine and leukotrienes from mast cells, neutrophils, and other inflammatory cells. It also inhibits the activation of eosinophils and neutrophils, and reduces cytokine production, thereby suppressing the immune response involved in aphthous ulcer formation.
| Metabolism | Amlexanox is primarily metabolized via glucuronidation and sulfation; oxidative metabolism is minimal. The exact enzymes have not been fully characterized, but it is not significantly metabolized by cytochrome P450 (CYP) enzymes. |
| Excretion | Renal excretion of unchanged drug and metabolites accounts for approximately 50-60% of the administered dose, with the remainder eliminated via biliary/fecal routes as metabolites and unchanged drug. Biliary excretion constitutes about 20-30%. |
| Half-life | Terminal elimination half-life is 1.5 to 2.5 hours. This short half-life supports multiple daily dosing for local therapeutic effect with minimal systemic accumulation. |
| Protein binding | Approximately 10% bound to serum proteins, primarily albumin. |
| Volume of Distribution | 0.5 to 1.0 L/kg, indicating distribution primarily into extracellular fluid and minimal tissue binding, consistent with low systemic exposure after topical use. |
| Bioavailability | Topical: Bioavailability is negligible (<1%) due to limited systemic absorption through oral mucosa. Oral (if swallowed): Bioavailability is low (around 5%) due to extensive first-pass metabolism, but this route is not clinically used. |
| Onset of Action | Topical application: Onset of pain relief and reduction of inflammation occurs within 2-5 minutes after application to oral mucosa. |
| Duration of Action | Duration of clinical effect is approximately 2-4 hours after a single topical application. Repeated applications are needed for sustained effect during the day. |
Adults: 5 mg orally three times daily for 5 days.
| Dosage form | PASTE |
| Renal impairment | No adjustment required for mild to moderate renal impairment. Severe impairment (CrCl <30 mL/min): Use with caution; no specific dose adjustment established. |
| Liver impairment | No formal studies. Use with caution in severe hepatic impairment (Child-Pugh C). No specific dose adjustment recommended. |
| Pediatric use | Children <12 years: Not recommended. Children ≥12 years: Same as adult dosing (5 mg three times daily for 5 days). |
| Geriatric use | No specific adjustment required; consider age-related renal function decline. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for APHTHASOL (APHTHASOL).
| Breastfeeding | It is not known whether amlexanox is excreted in human breast milk. The M/P ratio has not been determined. Due to minimal systemic absorption from topical oral application, risk to nursing infant is likely low. Caution is advised; use only if clearly needed and monitor infant for adverse effects. |
| Teratogenic Risk | APHTHASOL (amlexanox) is classified as FDA Pregnancy Category B. Animal studies have not demonstrated teratogenic effects, but no adequate and well-controlled studies exist in pregnant women. Risk cannot be ruled out. First trimester: limited data; avoid unless clearly needed. Second and third trimesters: systemic absorption is minimal from topical oral use; theoretical fetal risk low, but use only if potential benefit justifies risk. |
■ FDA Black Box Warning
None
| Serious Effects |
["Known hypersensitivity to amlexanox or any ingredient in the formulation"]
| Precautions | ["Not for systemic use; apply only to oral mucosa.","Do not use in patients with known hypersensitivity to amlexanox or any component of the formulation.","If irritation or sensitization occurs, discontinue use.","For topical oral use only; avoid contact with eyes."] |
| Food/Dietary | Avoid hot, spicy, acidic, or abrasive foods (e.g., citrus, tomatoes, nuts) that may irritate ulcers. Rinse mouth after meals before applying paste. No known systemic food interactions. |
| Clinical Pearls |
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| Fetal Monitoring | No specific maternal or fetal monitoring is required for topical use of APHTHASOL, given negligible systemic absorption. However, standard prenatal care should continue. In case of accidental ingestion or prolonged use, consider monitoring for maternal and fetal systemic effects (none expected). |
| Fertility Effects | No human or animal studies have evaluated the effect of amlexanox on fertility. Based on the drug's minimal systemic absorption and lack of hormonal or gonadotoxic activity, significant impact on fertility is unlikely. |
| APHTHASOL (amlexanox oral paste 5%) is a topical anti-inflammatory and antiallergic agent for aphthous ulcers. Apply promptly at prodrome or early lesion stage to reduce pain and healing time. Avoid application to intact mucosa outside ulcers. Use four times daily after meals and at bedtime. Not for cutaneous or ophthalmic use. |
| Patient Advice | Apply a small dab directly to each ulcer after brushing teeth or eating. · Do not rub or spread; paste will adhere. Wash hands after application. · Use 4 times daily: after breakfast, lunch, dinner, and at bedtime. · Do not use for more than 10 days unless directed by healthcare provider. · Avoid eating or drinking for at least 30 minutes after application. · Do not share the tube with others. |