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Drug abuse in pregnancy: Marijuana, LSD, cocaine, amphetamines, alcohol, and opiates
Published in Hung N. Winn, Frank A. Chervenak, Roberto Romero, Clinical Maternal-Fetal Medicine Online, 2021
Jacquelyn C. Howitt, Anita Bublik-Anderson
The care of the pregnant opioid abuser during labor can be quite complicated. Specific recommendations include continuation of usual maintenance doses of methadone or buprenorphine in labor. (Methadone is used only to prevent withdrawal; it will not provide adequate analgesia.) Metha-done or other opiates (e.g., morphine) should be given when evidence of maternal withdrawal exists. Agonist-antagonist combinations should not be given, as they will provoke withdrawal. Similarly, naloxone should not be given to infants of opiate addicts in the delivery room, as it may provoke neonatal withdrawal.
Pharmacology of Opioids
Published in Pamela E. Macintyre, Stephan A. Schug, Acute Pain Management, 2021
Pamela E. Macintyre, Stephan A. Schug
Agonist–antagonist drugs derive their analgesic actions principally from the activation of one opioid receptor while acting as antagonists at another. All behave as partial agonists, meaning that they do not have the intrinsic activity of full agonists (Ogura & Egan, 2019). There is therefore a “ceiling” to both their analgesic and adverse effects (including OIVI), and once a certain dose level is reached administration of further doses will not improve analgesia or worsen side effects.
Endocrine Therapies
Published in David E. Thurston, Ilona Pysz, Chemistry and Pharmacology of Anticancer Drugs, 2021
Tamoxifen, previously marketed as NolvadexTM but generic since 2002, is a nonsteroidal antiestrogen that induces gonadotrophin release by occupying estrogen receptors in the hypothalamus, thus interfering with feedback mechanisms. It is antagonistic toward estrogen receptors in breast tissue via its active metabolite, 4-hydroxytamoxifen (Figure 8.4). However, in other tissues such as the endometrium (i.e., uterus) and bone it behaves as an agonist and so is often categorized as a mixed agonist/antagonist. Tamoxifen is on the World Health Organization’s “List of Essential Medicines”. Structure of tamoxifen and its 4-hydroxy and N-desmethy-4-hydroxy metabolites (i.e., Afimoxifene and Endoxifene, respectively).
Latest generation estrogen receptor degraders for the treatment of hormone receptor-positive breast cancer
Published in Expert Opinion on Investigational Drugs, 2022
Ya-Chi Chen, Jiajie Yu, Ciara Metcalfe, Tom De Bruyn, Thomas Gelzleichter, Vikram Malhi, Pablo D. Perez-Moreno, Xiaojing Wang
Elacestrant at dose ranges between 0.3 and 100 mg/kg was reported not to affect uterine wet weight or epithelial thickness in rats significantly [81]. However, in mouse uterine wet weight assessments, a statistically significant increase in uterine weight was observed with a single low dose (0.3 mg/kg) but not at doses above 1 mg/kg [74]. The latter observation suggested that elacestrant may exhibit dose-dependent agonist/antagonist activity, with antagonist activity manifesting at the higher dose levels [74]. Indeed, in an MCF-7 xenograft model, a similar magnitude of tumor growth stimulation was observed following treatment with lower doses of elacestrant (1 mg/kg or 3 mg/kg) to that previously reported for partial ER agonists, but this was not observed at the higher 10 mg/kg dose [74]. It remains to be seen how this complex pharmacology will impact the clinical use of elacestrant.
Extended-release morphine sulfate and naltrexone hydrochloride (EMBEDA): naltrexone-associated withdrawal and abuse-related effects in patients with chronic pain and recreational opioid users
Published in Current Medical Research and Opinion, 2019
Beatrice Setnik, Kenneth W. Sommerville, Glenn C. Pixton, Lynn Webster
Although opioid receptor agonist/antagonist combinations such as buprenorphine/naloxone have been available for the treatment of opioid dependence for a number of years11,12, the use of an agonist/antagonist combination is a new option for many physicians when treating chronic pain. Knowledge of the potential interactions between the agonist and antagonist is essential for the optimal use of this type of formulation. The objective of this article is to examine the effects of naltrexone across MSN studies: (1) to review the incidence of withdrawal-related adverse events (AEs) with MSN in patients with chronic pain, as well as the circumstances where this occurred; (2) to review the ability of naltrexone to mitigate euphoric effects when MSN is manipulated by recreational opioid users; and (3) to explore the relationship between plasma concentration of naltrexone and 6-β-naltrexol, an active metabolite of naltrexone, and the onset of symptoms of withdrawal.
Morphine sulfate abuse-deterrent formulations for the treatment of chronic pain
Published in Expert Review of Clinical Pharmacology, 2018
Andrea Fanelli, Maria Cristina Sorella, Daniela Ghisi
Johnson et al. reviewed three studies that determined the quantity of naltrexone released upon tablet crushing, the ability of released naltrexone to reduce morphine effects, and whether intact morphine and naltrexone morphine withdrawal [28]. In these studies, sequestered naltrexone in the agonist/antagonist formulation met the bioavailability criteria when compared to naltrexone injection alone while drug-liking and addiction scores were significantly reduced in the combined formulation versus morphine alone. After administration, 77% of patients did not have a detectable naltrexone concentration in their blood. Patients with the highest detectable concentration failed to demonstrate opioid withdrawal based on the clinician opioid withdrawal scale. When not taken intact, morphine + naltrexone demonstrated moderate opioid withdrawal symptoms. In a study on healthy volunteers, bioequivalence between morphine and naltrexone and extended-release morphine was reported [29].