Ollie asked
I've been prescribed 75 mg of Tamiflu and 200 mg of Tessalon (benzonate). Is it OK to take Zyrtec?
Answer
There are no drug interactions between Tamiflu (oseltamivir), benzonatate (Tessalon Perles), and cetirizine (Zyrtec). All are considered to be safe to take together. One thing that could be of theoretical concern is drowsiness. Both benzonatate and Zyrtec may cause drowsiness, although are generally well tolerated by most people.
Cetirizine is FDA approved for relief of symptoms related to allergies, but may have some beneficial effect on relief of runny nose, sneezing, and watery eyes in patients with the flu.
Information about Tamiflu
Tamiflu is an antiviral that helps to treat seasonal influenza virus A or B (common flu). The important thing to note about Tamiflu is that it must be initiated as soon as possible once symptoms begin. The first 48 hours are the most critical time to make sure that Tamiflu is started. After 48 hours, the effect is much less, but can sometimes still be used in complicated cases. Tamiflu has been shown to reduce the duration of flu-like symptoms by about 24-32 hours assuming it is started early enough. Common side effects of Tamiflu include headache, nausea, vomiting, and diarrhea.
Because of the severe flu season this year, there have been reported shortages of Tamiflu in the community. This has especially affected the supply of liquid Tamiflu, commonly used for children. Many patients have had to call several pharmacies to ensure they have supply. Tamiflu suspension can be compounded by using the capsules in emergent situations, but is not recommended if the commercial product is available.
Information about Tessalon Perles
Benzonatate is a non-opioid cough suppressant that essentially numbs the cough reflex. Benzonatate is similar in structure to anesthetics like tetracaine. Typically, this medication will start to work in about 15-20 minutes and lasts up to 8 hours. The brand name for benzonatate, Tessalon Perles, makes sense when noticing its resemblance to a pearl. Benzonatate is well tolerated, but may cause an allergic reaction, drowsiness, dizziness, and headache.
Information about Zyrtec
Zyrtec is a second-generation antihistamine and is thought to cause drowsiness in some patients and relatively more drowsiness than other second-generation antihistamines including Claritin (loratadine) and Allegra (fexofenadine). First-generation antihistamines including Benadryl (diphenhydramine) cross the blood-brain barrier and cause significantly more drowsiness than the second-generation antihistamines.
