Effects of Intranasal Epinephrine on Cerebrospinal Fluid Epinephrine Pharmacokinetics, Nasal Mucosa, Plasma Epinephrine Pharmacokinetics, and Cardiovascular Changes.

PURPOSE: We aimed to assess intranasal (IN) epinephrine effects on cerebrospinal fluid (CSF) absorption, nasal mucosa quality, plasma epinephrine pharmacokinetics (PK), and cardiovascular changes in dogs. METHODS: CSF epinephrine concentration was measured and nasal mucosa quality was evaluated after IN epinephrine 4 mg and one or two 4 mg doses (21 min apart), respectively. Maximum plasma concentration [Cmax], time to Cmax [Tmax], area under the curve from 0 to 120 min [AUC0-120], and cardiovascular effects were evaluated after epinephrine IN (4 and 5 mg) and intramuscular (IM; 0.3 mg). Clinical observations were assessed. RESULTS: After epinephrine IN, there were no changes in CSF epinephrine or nasal mucosa. Cmax, Tmax, and AUC1-120 were similar following epinephrine IN and IM. Epinephrine IN versus IM increased plasma epinephrine at 1 min (mean ± SEM, 1.15 ± 0.48 for 4 mg IN and 1.7 ± 0.72 for 5 mg IN versus 0.47 ± 0.11 ng/mL for 0.3 mg IM). Epinephrine IN and IM produced similar heart rate and ECG results. Clinical observations included salivation and vomiting. CONCLUSIONS: Epinephrine IN did not alter CSF epinephrine or nasal tissue and had similar cardiovascular effects as epinephrine IM. Epinephrine IN rapidly increased plasma epinephrine concentration versus epinephrine IM.

Does inhaled pollen enter the sinus cavities?

BACKGROUND: While there is evidence of an increased incidence of sinusitis in patients with allergic rhinitis, it is unclear whether an allergic process occurs in the sinus tissues per se. OBJECTIVE: The purpose of this study was to determine whether inhaled pollen reaches the sinus mucosa. METHODS: Tc99m labeled ragweed pollen was inhaled by five non-atopic adults. Imaging studies of the sinuses were performed with a tomographic rotating gamma camera. To determine the sensitivity of the technique, the nose and the maxillary sinuses of cadaver heads were painted with varying amounts of Tc99m and then similarly scanned. RESULTS: Scans of the cadaver heads showed clear resolution between the nasal cavity and the maxillary sinus. It was determined that 20 microci was the smallest amount of Tc99m that could be resolved to be in the sinuses. Scans of subjects showed intense activity in the nasal cavity but none in the paranasal sinuses despite the delivery of a supraphysiologic dose of Tc99m ragweed pollen. CONCLUSION: Inhaled ragweed pollen does not appear to enter the paranasal sinuses. It is unlikely that an inhaled antigen-IgE antibody reaction occurs in the sinus mucosa.