Morphine. 10mg tablets of slow release morphine sulphate (MST) tablets. The tablets outside of the blister pack show the front of the capsule. 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.