Substance abuse propoxyphene

Propoxyphene is chemically related to methadone but has low analgesic activity. Various studies have reported its potency at levels ranging from no better than placebo to half as potent as codeine, ie, 120 mg propoxyphene = 60 mg codeine. Its true potency probably lies somewhere between these extremes, and its analgesic effect is additive to that of an optimal dose of aspirin. However, its low efficacy makes it unsuitable, even in combination with aspirin, for severe pain. Although propoxyphene has a low abuse liability, the increasing incidence of deaths associated with its misuse has caused it to be scheduled as a controlled substance with low potential for abuse. 

Fetal microcephaly has been attributed to cocaine abuse during pregnancy (323). Urine toxicology confirmed the presence of morphine, benzoylecgonine, barbiturates, paracetamol, and propoxyphene. Analyses of amniotic fluid, placenta, and fetal serum and urine were also positive for these substances. The authors suggested that vascular disruption was the likely major mechanism of anomalies, both behavioral and malformative, due to prolonged exposure to cocaine in utero. 

Heroin was first synthesized from morphine over a century ago. Since then, it has become one of the most abused substances. Research into why it produces such powerful effects has led to the discovery of specific opiate receptors and endogenous opioids (enkephalins and endorphins). These peptides appear to be neurotransmitters involved with the sensation of pain and pleasure. A number of opiates and synthetic opioids are available and can lead to dependency, including morphine, heroin, propoxyphene (Darvon), methadone, meperidine (Demerol), pentazocine (Talwin), hy-dromorphone (Dilaudid), oxycodone (Percodan), and hydrocodone (Vicodin, Damason-P), and codeine. 

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