Disclosed is the use of an anti-infective agent of formula (I) where the substituents are as disclosed in the description, in the manufacture of a medicament for the treatment or prophylaxis of an infectious disease, the medicament comprising 0.1 to 3000 mg of the anti-infective agent. Examples of compound of formula (I) include N-dealkyl-flupenthixol and N-dealkyl-clopenthixol. Also disclosed is the method of treating a non-human animal by administering a compound of formula (I). Further disclosed is a pharmaceutical composition comprising 0.1 to 3000 mg of an agent as defined by formula (I) and at least one pharmaceutically acceptable carrier or excipient, wherein said composition is in a unit dosage form.
