Does order some medicine (4)
I believe the answer is:
dose
'medicine' is the definition.
(dosing is a kind of medicining)
'does order' is the wordplay.
'order' indicates an anagram.
'does' with letters rearranged gives 'DOSE'.
'some' acts as a link.
(Other definitions for dose that I've seen before include "Measure of drug" , "Prescribed amount of medicine" , "Measured quantity of medicine" , "Medicinal quantity" , "some Viagra, perhaps?" .)