Morphine. Two 10mg tablets of slow release morphine sulphate (MST). One tablet is seen from the front and the other from the back. The opiate (derived from opium) morphine is an analgesic (painkilling) drug which is often used to numb pain during and after surgical procedures. It is also used to give pain relief to terminally ill patients. It may also be administered into the bloodstream from a syringe or through an intravenous drip.