The present invention relates to the delivery of opioids through an inhalation route. Specifically, it relates to aerosols containing opioids that are used in inhalation therapy. In a method aspect of the present invention, an opioid is delivered to a patient through an inhalation route. The method comprises: a) heating a composition, wherein the composition comprises an opioid, to form a vapor; and, b) allowing the vapor to cool, thereby forming a condensation aerosol comprising particles with less than 5% opioid degradation products. In a kit aspect of the present invention, a kit for delivering an opioid through an inhalation route is provided which comprises: a) a thin coating of an opioid composition and b) a device for dispensing said thin coating as a condensation aerosol.