sleeping tablet vs sleeping capsule

sleeping tablet and sleeping capsule both are nouns.

Word	Noun	Adjective	Verb	Adverb
sleeping tablet	Yes	No	No	No
sleeping capsule	Yes	No	No	No

As nouns, sleeping tablet and sleeping capsule are synonyms defined as:

sleeping tablet and sleeping capsule: a soporific drug in the form of a pill (or tablet or capsule)

Other synonyms of sleeping tablet include sleeping draught, sleeping pill.

sleeping tablet (noun)	sleeping capsule (noun)
a soporific drug in the form of a pill (or tablet or capsule)	a soporific drug in the form of a pill (or tablet or capsule)