immune suppressant drug

NOUN
23 LETTERS · STARTS WITH I

immune suppressant drug is a valid 23-letter word worth 31 points in Scrabble and 41 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
I1M3M3U1N1E1S1U1P3P3R1E1S1S1A1N1T1D2R1U1G2
1 + 3 + 3 + 1 + 1 + 1 + 0 + 1 + 1 + 3 + 3 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 0 + 2 + 1 + 1 + 2 =31 PTS
DOUBLE WORD → 62TRIPLE WORD → 93
MEANING

What does immune suppressant drug mean?