There are no official guidelines to assist in answering this question. I will search for relevant research papers instead.
The FDA Drug Labels for fexofenadine (PO) do not address this question.
From the Research
Fexofenadine for Acute Sinusitis
- The provided studies do not directly address the use of fexofenadine for acute sinusitis, but rather its efficacy in treating allergic rhinitis and nasal congestion.
- Fexofenadine has been shown to be effective in reducing nasal congestion in patients with allergic rhinitis, as demonstrated in studies 1, 2, 3.
- A review of allergic rhinitis treatment options suggests that second-generation H1 antihistamines, such as fexofenadine, may be used as first-line treatment for mild intermittent or mild persistent allergic rhinitis 4.
- Fexofenadine has also been shown to have anti-inflammatory effects, reducing inflammatory mediators in nasal lavage fluid in patients with intermittent allergic rhinitis 5.
Nasal Congestion and Allergic Rhinitis
- Nasal congestion is a common symptom of allergic rhinitis, and fexofenadine has been shown to be effective in reducing nasal congestion in patients with allergic rhinitis 1, 2, 3.
- The mechanism of action of fexofenadine in reducing nasal congestion is thought to be related to its anti-inflammatory effects, as demonstrated in study 5.
Limitations
- The provided studies do not directly address the use of fexofenadine for acute sinusitis, and therefore the evidence is not directly relevant to this question.
- Further studies would be needed to determine the efficacy of fexofenadine in treating acute sinusitis.