Compounds of general structure in which X and Y are each N or C with at least one of X and Y being N; Z is a single bond or an optionally substituted linking group R1 is hydrogen or a substituent group; R2 is amino or a substituent group; N* is amino when RI is hydrogen or ═NH when R1 is a substituent group; or N* is a group NRaRb where Ra and Rb are independently H or an alkyl group; or N* is an optionally substituted piperazinyl ring; and A is an optionally substituted heterocyclic or carbocyclic ring system which may be linked to the triazo/diazo ring through R2 to form a fused multicyclic ring; are indicated as suitable for treatment of disorders in mammals that are susceptible to sodium channel blockers and antifolates, and particularly disorders such epilepsy, multiple sclerosis, glaucoma and uevitis, cerebral traumas and cerebral ischaemias, stroke, head injury, spinal cord injury, surgical trauma, neurodegenerative disorders, motorneurone disease, Alzheimer's disease, Parkinson's disease, chronic inflammatory pain, neuropathic pain, migraine, bipolar disorder, mood, anxiety and cognitive disorders, schizophrenia and trigeminal autonomic cephalalgias; for treatment of mammalian cancers; and for treatment of malaria.