For Allergic Rhinitis I was prescribed Claritin by my ENT. I was told to take it every morning, which I did, but after a few hours of taking it, I would get the worst neck pain/head aches. On Jul 28, 2000. Yes my kids have been on zyrtec under the age of two.as far as dosage I can't remember. All three take 10 mg. of it daily now, they used to take 5, but due to their high grass allergy they need a higher dosage of the 10 mg. User Reviews for Zyrtec. The following information is NOT intended to endorse drugs or recommend therapy. While these reviews might be helpful, they are not a substitute for the expertise, skill, knowledge and judgement of healthcare practitioners in patient care. Per the US FDA package insert for Zyrtec (cetirizine hcl) 10mg tablets: adults and children 12 years and older should not take more than the 24hr recommended maximum dose of 10mg. Cetirizine is an allergy medication that you can buy over-the-counter at a pharmacy. That is, you don’t need a prescription. The medication comes in capsules, tablets, and a syrup. Doctors give trusted answers on uses, effects, side-effects, and cautions: Dr. Menchell on can i take claritin and dayquil: DayQuil contains PHENYLEPHRINE a DECONGESTION similar to SUDAPHED! Rapid heart beat and a number of other symptoms are possible! Hope this helps! Dr Z To the people that took zyrtec, did you have a hard time getting off of Zyrtec? Atarax works well for me, but I decided to take Zyrtec because you don't need a prescription. Horrible recommendation. Do not take extra doses of the antihistamine if you've already experienced terrible effects of withdrawal. You are in the 1% of the population that likely experiences these effects, but they won't go away -- you'll be addicted to Zyrtec for life. Doctors give trusted answers on uses, effects, side-effects, and cautions: Dr. Singla on can you take 2 claritin: If your symptoms are not controlled with a normal dose, you should be evaluated for other causes and treatments. 2nd-generation antihistamines like Claritin (loratadine) are usually very safe, and we sometimes recommend doses higher. I think Zyrtec is blocking it off as much as it can. I was thinking about taking flonase, I did some research and what I found out was that it's a steriod.