Yes, HYDRALAZINE is a Scrabble word!

Letter values in Scrabble US: H 4, Y 4, D 2, R 1, A 1, L 1, A 1, Z 10, I 1, N 1, E 1.

Is it a valid word?

HYDRALAZINE is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

an antihypertensive drug (trade name Apresoline) that dilates blood vessels; used (often with a diuretic) to treat hypertension and congestive heart failure

Not playable in Scrabble US: APRESOLINE.