Brief Answer:
Yes. You can take Excerdin for Headache.

Detailed Answer:
Hello,
Welcome to XXXXXXX

I have gone through your query and understand your concern.

Mucinex fast XXXXXXX contain dextromethorphan, guaifenesin, and phenylephrine.

Dextromethorphan is a cough suppressant.
Guaifenesin is an expectorant.
Phenylephrine is a decongestant.

Claritin contains Loratidine.

Loratidine is an antihistamine.

Excedrin contains a combination of acetaminophen, aspirin, and caffeine.

All these tablets are recommended in a prescribed dose.
There is no major interaction between these drugs.

You can take Excerdin Now for for your Headache.

Hope this helps.
Please reply for further queries.
Wishing you good health.

---