Analgesic. A container with capsules of the analgesic (painkilling) drug Tylex. Tylex is known as a compound analgesic preparation. This is where the capsules contain a mixture of paracetamol and codeine. Paracetamol is a painkiller used to treat mild pain (for example toothache or headache) and to reduce fever. Codeine is an analgesic opiate (derived from the opium poppy plant). Although codeine has amongst the weakest effect of the opiates, it is stronger than paracetamol. Tylex is therefore used to treat mild to moderate pain, coughs and diarrhoea.