A. Drugs that are used for the same or similar purpose or on/in the same part of the body are descr?

I'll break down the words for you but the rest you can do with Google. It's best you do this yourself anyway as OTC remedy names vary from country to country and there's no guarantee we are from the same country.

1. An algesic (without pain)
2. Anti pyretic (against fire or burning)
3. Anti histamine (against the action of histamine)
4. Anti tussive (against tussis, which is coughing)
5. De congestant (clearing congestion)
6. Broncho dilator (to open the bronchi/bronchioles)
7. Ant(i) acid (to neutralise acid)
8. Anti emetic (against being sick)
9. Lax ative (to make lax or unfirm)
10. Anti spasm odic (to prevent spasms)

11. Ant(i) helmintic (against helminths or worms)
12. Anti pruritic (against pruritis or itching)
13. E mollient (to mollify or - in the case of skin - to make it softer)
14. Anti septic (against sepsis or infection)
15. Anti fungal (against fungal infection)
16. Anti mycotic (against myco infections, which include bacteria and fungus)
17. Contraceptive (control conception, wrongly known as birth control)
18. Derma tological (of the dermis, or skin)
19. Ophthalmo logical (the study of the eye)
20. Oto logic (the study of the ear)