Doctors give trusted answers on uses, effects, side-effects, and cautions: Dr. Andrews on delsym and benadryl: Either the recommended amount based on weight through the directions on the box or following your doctors recommendations if the recommended dose they made is higher. looking for a good cough suppressant for my 29 year old daughter who is suffering with the latter stages of a bad cold….a hacking cough day and night. I appreciate this site and the good information I am finding here. Thank you kindly for the time invested in helping us. I used to take Zyrtec or Benadryl, but lately am feeling very bad when I do. Allegra and Zyrtec may cause mild side effects that tend to go away as your body gets used to the drug. Most of these don’t call for medical attention. At least once or twice a week the smallest thing, like drinking water, or soda, or even taking in a breath, will trigger a tickle in my throat which sends me into a coughing fit until my eyes water and usually end with sneezing. No locations found within 50 miles of selected location. Please double check your entry and try again. Both Xyzal and Zyrtec are effective over-the-counter allergy relief drugs with a very similar chemical makeup. Both are likely to make you less drowsy than alternatives such as Benadryl. Whether you have a cough due to a cold, the flu, allergies or dry winter air, the array of cough medicine options can be confusing. Upper-respiratory infections, like a cold or the flu, are the most common cause of cough. Helpful, trusted answers from doctors: Dr. Gani on how to dry up mucus in lungs: Add nebulize saline. Savings Alert: Mucinex d is available over-the-counter. You can use GoodRx coupons to save, but you will need to present a doctor’s prescription and purchase at the pharmacy counter.