Not Medical Advice: The white pill with M2A4 57344 imprint has been identified as Acetaminophen 500 mg.
Acetaminophen is a pain reliever and a fever reducer, it belongs to the drug class miscellaneous analgesics.
Acetaminophen is a generic for Tylenol, an analgesic (pain relievers) and antipyretic (fever reducer). It is used in the treatment of pain associated with many conditions such as headache, muscle aches, arthritis, backache, toothaches, colds, sciatica, plantar fasciitis, fevers and more.
If used appropriately, side effects with acetaminophen are not common. The most serious side effect is liver damage due to large doses.
Check out some tips for living with chronic pain at WebMD.