From the Research
Hydroxyzine should be used with caution or avoided in patients with hypercapnia (elevated CO2 levels of 43 mmHg). The standard adult dosage of hydroxyzine for anxiety is 25-100 mg 3-4 times daily, and for allergic conditions 25 mg 3-4 times daily, but these doses should be reduced by 30-50% in patients with respiratory compromise, as suggested by the need to balance efficacy with the potential for increased sedation and respiratory depression 1. Treatment duration should be limited to the shortest period necessary, typically not exceeding 2 weeks in hypercapnic patients. Hydroxyzine has sedative properties that can further depress respiratory drive, potentially worsening hypercapnia. Its anticholinergic effects may also thicken respiratory secretions, making clearance more difficult. Alternative non-sedating antihistamines like loratadine or cetirizine would be safer choices for these patients, given their lower risk of sedation and similar efficacy for allergic conditions 2. If hydroxyzine must be used, start with the lowest effective dose, monitor respiratory status closely, and consider pulmonology consultation. Underlying causes of hypercapnia should be addressed concurrently with any symptomatic treatment.
Some key points to consider when using hydroxyzine in patients with hypercapnia include:
- Monitoring for signs of respiratory depression or worsening hypercapnia
- Adjusting the dose to minimize sedative effects while still providing therapeutic benefit
- Considering alternative treatments that do not have the same level of sedation or respiratory risk
- Addressing the underlying cause of hypercapnia to prevent further complications
It's also important to note that while hydroxyzine has been studied for various conditions, including anxiety and allergic reactions 3, 4, its use in patients with hypercapnia requires careful consideration of the potential risks and benefits. A more recent study highlighting the risks of hydroxyzine, such as the potential to induce torsade de pointes in certain patients 5, further emphasizes the need for caution when prescribing this medication, especially in vulnerable populations.