A clear, colourless liquid with a penetrating ethereal odour, paraldehyde may be given by mouth, rectally, or occasionally in intramuscular injection. Used off licence, its prime function is as an anticonvulsant in STATUS EPILEPTICUS (after initial intravenous DIAZEPAM) and in TETANUS. Its unpleasant taste and the need to give the PARENTERAL version through a glass syringe as it dissolves plastic, restricts its use.

Adverse effects include CAUSALGIA and rashes; pain and sterile ABSCESS after intramuscular injection; and rectal irritation after ENEMA.