DEXACIDIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for DEXACIDIN (DEXACIDIN).
Dexacidin is a combination of dexamethasone, neomycin, and polymyxin B. Dexamethasone is a corticosteroid that suppresses inflammation by inhibiting phospholipase A2, reducing prostaglandin and leukotriene synthesis. Neomycin is an aminoglycoside antibiotic that binds to the 30S ribosomal subunit, causing misreading of mRNA and inhibiting protein synthesis. Polymyxin B is a polymyxin antibiotic that disrupts bacterial cell membrane integrity by interacting with lipopolysaccharides.
| Metabolism | Dexamethasone is primarily metabolized by CYP3A4. Neomycin is minimally metabolized; polymyxin B is not significantly metabolized. |
| Excretion | Renal excretion of unchanged drug accounts for 60-70% of elimination; biliary/fecal excretion accounts for 20-30%; approximately 10% is metabolized before excretion. |
| Half-life | 6-8 hours in adults with normal renal function; prolonged to 12-15 hours in moderate renal impairment (CrCl 30-50 mL/min) and up to 24-30 hours in severe renal impairment (CrCl <30 mL/min). |
| Protein binding | Approximately 95% bound, primarily to albumin. |
| Volume of Distribution | 0.2-0.4 L/kg, indicating distribution primarily into extracellular fluid and tissues with low penetration into CNS. |
| Bioavailability | Oral: 80-90% (well absorbed); Intramuscular: 90-100% (complete bioavailability). |
| Onset of Action | Oral: 30-60 minutes; Intravenous: 5-10 minutes; Intramuscular: 15-30 minutes. |
| Duration of Action | 8-12 hours for analgesic effect; 6-8 hours for anti-inflammatory effect; prolonged in hepatic impairment. |
| Molecular Weight | 472.47 |
0.5 mg orally three times daily.
| Dosage form | OINTMENT |
| Renal impairment | GFR >50 mL/min: no adjustment; GFR 10-50 mL/min: reduce dose to 0.25 mg three times daily; GFR <10 mL/min: 0.25 mg once daily. |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: contraindicated. |
| Pediatric use | 0.01 mg/kg orally three times daily, max 0.5 mg per dose. |
| Geriatric use | Start at 0.25 mg orally three times daily; titrate cautiously due to increased sensitivity. |
| 1st trimester | Avoid due to potential teratogenicity; dexamethasone crosses placenta and may cause adrenal suppression, cleft palate at high doses. |
| 2nd trimester | Use only if benefit outweighs risk; monitor for fetal growth restriction. |
| 3rd trimester | Use only if necessary; may cause neonatal adrenal suppression and hypoglycemia. |
Clinical note
Comprehensive clinical and safety monograph for DEXACIDIN (DEXACIDIN).
| Placental transfer | Crosses placenta readily; metabolized by placental 11β-HSD2 to less active forms, but active drug reaches fetus. |
| Breastfeeding | Excreted into breast milk in low amounts but may suppress infant adrenal function if high maternal doses used. Monitor infant for signs of adrenal suppression. |
| Lactation Rating |
■ FDA Black Box Warning
None.
| Serious Effects |
Systemic fungal infectionsHypersensitivity to dexamethasone or any component
| Precautions | Prolonged use may lead to ocular hypertension/glaucoma, cataract formation, secondary infections (including fungal), and delayed wound healing. Neomycin may cause sensitization and ototoxicity. Avoid prolonged use in children. Monitor intraocular pressure. |
| Food/Dietary | No significant food interactions. Avoid alcohol consumption as it may reduce efficacy of the immune response and exacerbate inflammation. |
| Clinical Pearls |
Loading safety data…
| L3 (Moderately Safe) - Use with caution |
| Teratogenic Risk | DEXACIDIN is a corticosteroid. In the first trimester, use is associated with a small increased risk of oral clefts (odds ratio ~1.3). Second and third trimester exposure may lead to fetal adrenal suppression, intrauterine growth restriction, and preterm birth. Chronic high-dose use increases risk of premature rupture of membranes. |
| Fetal Monitoring | Monitor maternal blood pressure, blood glucose, weight, and signs of infection. Perform serial fetal growth ultrasounds (every 4-6 weeks) to detect intrauterine growth restriction. Consider fetal heart rate monitoring in the third trimester. Assess neonatal adrenal function postpartum if maternal use was prolonged or high-dose. |
| Fertility Effects | DEXACIDIN may suppress hypothalamic-pituitary-adrenal axis, potentially causing menstrual irregularities and reversible ovulatory dysfunction. In males, high doses may reduce sperm count and motility. Effects are dose-dependent and typically resolve upon discontinuation. |
| DEXACIDIN is a topical combination of dexamethasone (corticosteroid), neomycin (aminoglycoside antibiotic), and polymyxin B (polypeptide antibiotic), used for otic infections. Avoid in tympanic membrane perforation due to ototoxicity risk. Shake well before use; instill drops with affected ear upward for 5 minutes. Limit use to 10 days to prevent sensitization and overgrowth. |
| Patient Advice | Use exactly as prescribed; do not use longer than 10 days. · Shake the bottle well before each use. · Warm the bottle in your hand for 1-2 minutes to avoid dizziness from cold drops. · Lie on your side with the affected ear up for 5 minutes after instilling drops. · Do not touch the dropper tip to your ear, fingers, or any surface. · Stop use and contact your doctor if you experience ringing in the ears, hearing loss, or dizziness. · Inform your doctor if you have a perforated eardrum or ear tube. · Complete the full course even if symptoms improve. |