intranasale

Intranasal administration is a route for delivering drugs through the nasal cavity. It is used for both local nasal therapy and systemic effects, offering a non-invasive and relatively rapid method of drug delivery. Absorption occurs across the nasal mucosa, which is richly supplied with blood vessels and can allow quick entry into the systemic circulation.

Common formulations include nasal sprays, drops, gels, and powders. Metered-dose nasal sprays are widely used for systemic medications. Intranasal vaccines, such as certain live attenuated influenza vaccines, stimulate immunity via the nasal mucosa. Other examples include naloxone nasal spray for opioid overdose and sumatriptan nasal spray for migraine attacks.

Pharmacokinetics involve absorption across the nasal epithelium, with potential systemic exposure or local action within the nasal passages. The nasal mucosa’s high vascularity can support rapid onset, and some agents may reach the brain via olfactory or trigeminal pathways. Bioavailability is highly variable and depends on the drug’s properties, formulation, and the condition of the nasal passages.

Advantages of intranasal delivery include avoidance of first-pass metabolism in the liver and bypassing the gastrointestinal tract, ease of self-administration, usefulness for patients who cannot swallow, and the potential for rapid relief in acute situations.

Limitations and considerations include reduced absorption due to nasal congestion, inflammation, or structural abnormalities. Drug suitability depends on molecular properties for mucosal permeation. Local adverse effects can include irritation, burning, sneezing, or nosebleeds. Proper device use, hygiene, and patient selection are important, and regulatory status varies by product.