01.09.2 Nasal Mucosa

The nasal mucosa is highly porous and permeable to drugs. The nasal mucosa is highly vascularised. The nasal mucosa also has a relatively large surface area as a result of microvilli on the epithelial cells, and this aids absorption from the nasal mucosa. One disadvantage to the nasal route is that the drug may be rapidly removed by a runny nose. Thus, it is an unreliable route of administration in subjects with a cold or hayfever.

Recently there has been an increased use of the intranasal route for the emergency/quick effect of drugs. For example, intranasal midazolam is used in the hospital setting to quickly stop an attack of status epilepticus.

Most of the drugs that are commonly administered intranasally are those with effects on the nose. For example, decongestants (such as pseudoephedrine) are administered into the nose, when it is congested in a cold.