Because inhalant abuse may lead to the development of life-threatening symptoms, close attention should be directed to the stability of vital signs over time Patients with depressed levels of consciousness may require airway support and ventilation Because of the risk of cardiac arrhythmias when halogenated hydrocarbons are abused, vascular access should be established early Dysrhythmias should be treated according to the standard protocol; however, the use of epinephrine is relatively contraindicated because it may worsen rhythm disturbances As a part of the evaluation, obtain a complete metabolic panel that includes electrolyte levels, with calcium, phosphate, and magnesium; amylase level; liver function tests; creatine phosphokinase level; and urinalysis Treatment of methemoglobinemia is discussed in Chapter 93 Hematologic Emergencies OTHER EMERGING DRUGS OF ABUSE Current Evidence In recent years, use of the so-called “designer drugs” or synthetic drugs of abuse has markedly increased, in part due to the fact that many of these substances were originally sold at head shops, convenience stores, and over the internet as “legal highs.” The Synthetic Drug Abuse Prevention Act of 2012 placed many of the most commonly identified compounds into Schedule I status, though new derivatives and formulations continue to be produced and distributed Staying up to date with these emerging substances of abuse can be challenging for providers Your local poison control center and public health department can be helpful resources when caring for a patient with possible exposure to one of these agents Given their particular popularity, the synthetic cathinones are described in further detail below, and synthetic cannabinoids in the section on cannabis Other important classes of these so-called designer drugs include the 2C class of drugs (phenylethylamine derivatives with sympathomimetic, hallucinogenic, and serotonergic features) and piperazines (sympathomimetic features predominate) Cathinones Cathinones are naturally occurring substances found in the leaves of the khat (Catha edulis) plant For centuries, people have chewed the leaves of this plant for the euphoric and stimulant effects Synthetic cathinone derivatives were first synthesized in the 1920s, but use among recreational drug users noticeably escalated in 2010–2011 These substances were initially sold as bath salts or plant food and labeled as “not for human consumption.” Nasal insufflation and