NASAREL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for NASAREL (NASAREL).
Corticosteroid that binds to glucocorticoid receptors, inhibiting inflammatory mediators such as prostaglandins, leukotrienes, and cytokines, thereby reducing nasal inflammation.
| Metabolism | Primarily hepatic via CYP3A4 isoform; undergoes extensive first-pass metabolism. |
| Excretion | Primarily hepatic metabolism; renal excretion of metabolites accounts for <30% of dose. Fecal elimination minimal (<5%). |
| Half-life | Terminal half-life approximately 15-25 minutes for flunisolide (the active ingredient in NASAREL) in the systemic circulation after intranasal administration. Clinically, the half-life is short, reducing the risk of systemic accumulation but requiring twice-daily dosing for consistent effect. |
| Protein binding | Approximately 40-50% bound to plasma proteins, primarily albumin. |
| Volume of Distribution | Volume of distribution is approximately 1.4–2.0 L/kg after IV administration, indicating extensive tissue distribution. For intranasal use, the Vd is not directly applicable but reflects systemic exposure if absorbed. |
| Bioavailability | Intranasal: Systemic bioavailability is approximately 21% (range 10-50%) due to first-pass metabolism. Oral bioavailability is <1% due to extensive hepatic first-pass effect. The drug is administered intranasally for local effect with low systemic exposure. |
| Onset of Action | Intranasal: Symptom relief begins within 12-24 hours, with full therapeutic effect achieved after several days of regular use. |
| Duration of Action | Duration of clinical effect is approximately 12-24 hours, supporting twice-daily dosing (e.g., 2 sprays each nostril BID). Maximal benefit may take up to 2 weeks. |
2 sprays (50 mcg/spray) in each nostril once or twice daily; maximum 8 sprays/day.
| Dosage form | SPRAY, METERED |
| Renal impairment | No dose adjustment required for renal impairment. |
| Liver impairment | No dose adjustment required for hepatic impairment. |
| Pediatric use | Children 6-11 years: 1 spray in each nostril once daily; maximum 4 sprays/day. Children ≥12 years: same as adult. |
| Geriatric use | No specific dose adjustment; use lowest effective dose. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for NASAREL (NASAREL).
| Breastfeeding | It is not known whether flunisolide is excreted in human milk. Because many corticosteroids are excreted in human milk, caution should be exercised when Nasarel is administered to a nursing woman. M/P ratio not available. Use with caution; consider using lowest effective dose and monitoring infant for signs of adrenal suppression. |
| Teratogenic Risk | FDA Pregnancy Category C: In animal studies, corticosteroids have been shown to be teratogenic at high doses. No adequate and well-controlled studies in pregnant women. Nasarel (flunisolide) should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. First trimester: Theoretical risk of cleft palate; avoid systemic absorption by using minimal effective dose. Second and third trimesters: No specific risks reported; monitor for fetal adrenal suppression if used chronically at high doses. |
■ FDA Black Box Warning
None
| Serious Effects |
["Hypersensitivity to flunisolide or any component of the formulation","Untreated localized nasal infections (e.g., bacterial, fungal, viral)"]
| Precautions | ["May cause epistaxis, nasal septal perforation, or nasal mucosal ulceration","Potential for systemic corticosteroid effects with prolonged use","May suppress hypothalamic-pituitary-adrenal (HPA) axis, especially at higher doses","Increased susceptibility to infections; avoid in active untreated infections","Use with caution in patients with tuberculosis, ocular herpes simplex, or untreated fungal/bacterial infections"] |
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| Fetal Monitoring | Monitor maternal adrenal function if using high doses or long-term therapy. Assess fetal growth via ultrasound if used throughout pregnancy. Monitor infant for adrenal suppression postnatally if maternal use was prolonged. |
| Fertility Effects | No specific studies on fertility in humans. In animal studies, corticosteroids may impair fertility at high doses. Theoretical risk of reversible menstrual irregularities with systemic absorption; intranasal route minimizes systemic exposure. |