Pill Identification by Imprints: M 1840 Home Pill Identification by Imprints: M 1840 1 result METHYLPHENIDATE ER 40 MG CAP Side 1: M 1840 Color: Yellow Side 2: 40 mg Shape: Oblong Other Popular Drug Imprint 471 WPI 3699 M1000 ZA-37 2632 44 113 P 400 499 GXL 5 RX 901 52H 52H AC356 SG 326 logo and 4356 83 80 mg PROCARDIA PFIZER 260 logo and 290 V267 W 1033 E 720 PTLA logo U03 85 54 551 TEMODAR 57 55 logo and 1000-40 S903 42 S592 PAC20 C43 382 PERCOCET 5 MSD 117 ED UB USL 8 P20