Methamphetamine drug interactions

Ephedra has been closely linked to methamphetamine production. There are movements In many localities to outlaw the herb. There are many drug interactions with Ma huang. )9-BI(K kcrs may enhance the sympathetic effect and cause hypertentiion. MAOIs may interact with ephedra to cause hypertensive cri.si.s. Phcnothiaz.ines might block the or effects of ephedra, causing hypotension and tachycardia. Simultaneous use of theophylline may cau.se GI and CNS effects. In pregnancy, ephedra is absolutely contraindicated (uterine stimulation). Persons with heart disease, hypertension, and diabetes should not take ephedra. 

Much remains unknown about melatonin s interaction with many other drugs and substances. However, it is known that melatonin does interact with, and may limit the effectiveness of, benzodiazepines, methamphetamines, dehydroepiandrosterone, magnesium, zinc, corticosteroids, and succinylcholine. People who are being treated with these drugs should not take melatonin. 

Many recreational drugs such as benzodiazepines, amphetamines, and opioids are also metabolized by the liver. Although information is scant about the clinical significance and interactions between these drugs and antiretroviral agents, unintentional overdoses with methamphetamine and gamma hydroxybutyrate have been reported in patients using Pis, particularly ritonavir. Pis and NRTIs may alter metabohsm of methadone and precipitate opioid withdrawal (McCance-Katz et al., 2003). 

The stereochemistry of drugs and precursors can be vital in determining synthetic routes. Horvever, since enantiomers are nearly chemically identical, standard chromatographic methods cannot separate them. To effect a chromatographic separation of enantiomers, stereospecific interactions have to be incorporated. As described in Chapter 5, the use of chiral stationary phases is one method of discriminating enantiomers while capillary electrokinetic chromatography (MEKC) using chiral cy-clodextrins is another. Both of these protocols have been applied to methamphetamine and related compounds and precursors, substances that will be discussed in detail later in the chapter. 

Three stationary phases were evaluated for the UHPLC separation of fourteen illicit and licit drugs (Figure 9.1). A polar endcapped C18 phase did not resolve the early eluting compounds, including amphetamine, methamphetamine, hydrocodone, oxycodone, caffeine, and MDMA, due to secondary interactions with the polar analytes. A C18 phase showed improved selectivity for all analytes except caffeine (peak 1) and oxycodone (peak 7). A pentafluorophenyl (PFP) phase produced the optimal separation of all fourteen drugs, dramatically improving the resolution of the earlier eluting compounds. 

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