Medicines to Japan

My son is coming soon to Tokyo, Narita.
He has asthma and allergies and I'm worried about him bringing his medicines.
I understand it is not possible to bring sinus medicines.
Is he able to bring his:
-Asthma inhalers
-Allergy tablets - Benadryl(acravastine) NOT the old diphenhydramine type.
-Paracetamol
-Imodium
-Lansoprosil
-Nasal saline solutions (Neilmed)
Does he need to declare them on a customs form?
thank you

Travelers entering to Japan, are allowed as a special case has brought the medicine only if personal use.
http://japan.usembassy.gov/e/acs/tacs-medimport.html

thank you for your reply but we are uk

It is still prohibited to bring medicine which contains illegal substances in Japan, even for personal use. Also, it depends how much time he plans to stay in Japan (for long stays, you need to obtain permission before leaving your country, for any type of medication). If you are unsure whether a substance is permitted or not, you should contact the Health Ministry.

thank you for your reply but we are uk

That doesn't matter, the rules don't differ by country.

I will agree that Firas says. The immigrants from overseas (including UK) to Japan, bringing the drug for personal use, are allowed in restricted. External medicine for up to 24 pieces per item. Prescription drugs is up to that amount required for one month.
http://www.mhlw.go.jp/english/policy/health-medical/pharmaceuticals/01...
Your son, it is necessary to fill in the Customs Declaration Form, the name and quantity of medicine to bring entry into Japan at the time, tell the customs officials, that then they are for personal use.
http://www.customs.go.jp/english/passenger/index.htm

I'm travelling with my family to Japan in July and it never crossed my mind that I need to make a declaration on some of the medications (for precaution/own use)which I intend to bring along. Is the following medications available in pharmacy :- Paracetemol, imodium, controloc, gaviscon and some other sinus medications. Do I need a doctor's prescription to get those medicines?

I was bringing some medicine into Japan as well in my earlier visit. As long as you bring your doctor's prescription along, it should really be smooth, as everything they need to know is on it.

Actually, I didn't encounter any problems or questions when entering Japan, more of when I was leaving.