Postoperative nausea and vomiting
Hemanshu Prabhakar, Charu Mahajan, Indu Kapoor in Manual of Neuroanesthesia, 2017
It can cause hyperglycemia that can be deleterious for neurosurgical patients. Hence, blood sugar should be closely monitored while using this drug. For those patients who are at moderate to high risk, combination therapy has shown to be more efficacious for PONV prophylaxis. Combination therapy should include drugs having different mechanisms and sites of action. As neurosurgeries are considered moderate to high risk, triple therapy regimens have been tried in various studies. Some antiemetics (anticholinergics, antihistamines, benzamides, and butyrophenones) can cause sedation and interfere with neurocognitive monitoring, which precludes the use of such drugs in neurosurgical patients. One of the triple therapy regimens studied in neurosurgery includes droperidol, promethazine, and dexamethasone, which allows smaller doses of each agent when used together. This practice was affected by the increased warnings and contraindications for droperidol issued by the Food and Drug Administration (FDA). Even though droperidol has been issued a black box warning, studies have shown that QTc prolongation is equal to ondansetron in clinically relevant dosage. Droperidol was replaced by transdermal scopolamine (TDS) in the triple therapy regimen along with dexamethasone and ondansetron. Scopolamine was found to be equally or more effective but was associated with certain undesirable side effects, such as dry mouth, dizziness, blurred vision, and disorientation. Recently, a new drug category, NK-1 receptor inhibitors, is being tried in neurosurgical patients. Tsutsumi et al. found that NK-1 receptor antagonists are more efficacious in preventing PONV in neurosurgical patients. Bergese et al included aprepitant in triple-drug therapy along with promethazine and dexamethasone, and compared it with the ondansetron, promethazine, and dexamethasone combination. The results of this trial are awaited. Certain nonpharmacological treatments, such as acupuncture, acupressure, and electrical stimulation at the P-6 point, were also found to be a good adjuvant with standard antiemetic treatment. Various mechanisms have been described through which P-6 stimulation prevents PONV. These are endogenous β-endorphin release in the CSF or a change in serotonin transmission via activation of serotonergic and noradrenergic fibers. The timing of stimulation has no effect on efficacy in preventing PONV. Ascertain the optimal approach to treatment of PONV: If the patient presents with PONV, look for the contributing factors first, including opioid patient-controlled analgesia (PCA) pumps, blood trickling down the throat, or an abdominal obstruction.After excluding the offending agents, rescue antiemetic therapy should be instituted.
Pharmacology of opioids
Pamela E. Macintyre, Stephan A. Schug in Acute Pain Management, 2014
Scopolamine (hyoscine) has also been used to treat nausea and vomiting (Gan et al., 2014). It is available as a transdermal patch and is particularly effective for movement-induced nausea and vomiting. It may be associated with significant anticholinergic side effects such as sedation, dry mouth, visual disturbances and confusion and is not widely used in the management of PONV.
Reproductive and Developmental Toxicity Studies by Cutaneous Administration
Rhoda G. M. Wang, James B. Knaak, Howard I. Maibach in Health Risk Assessment, 2017
Scopolamine is a prophylactic for motion sickness usually applied for therapeutic use by a transdermal patch system. There are no reports of potential adverse reproductive/developmental outcome in humans using scopolamine patches. A teratogenicity study in rabbits and fertility studies in rats, which achieved plasma levels approximately 100 to 500 times greater than those achieved in humans using a transdermal system, showed marginal embryotoxic effects and decreased maternal body weight, respectively. These animal studies suggest current usage of scopolamine in the transdermal system is not likely to produce adverse reproductive/developmental effects.
Microdialysis pharmacokinetic study of scopolamine in plasma, olfactory bulb and vestibule after intranasal administration
Published in Drug Delivery, 2016
Yan Wei, Mingzhen Ying, Shuai Xu, Feng Wang, Aifeng Zou, Shilei Cao, Xinguo Jiang, Yajie Wang
The purpose of this study was to investigate the microdialysis pharmacokinetic of scopolamine in plasma, olfactory bulb and vestibule after intranasal administration. The pharmacokinetic study of subcutaneous and oral administration was also performed in rats. From the in vivo results, scopolamine intranasal administration can avoid hepatic first-pass effect. Tmax plasma samples after intranasal administration were significantly faster than oral administration and subcutaneous injection. The relative bioavailability of intranasal administrations was 51.8–70% when compared with subcutaneous injection. Moreover, one can see that in comparison with scopolamine subcutaneous administration, scopolamine intranasal gel and solutions can increased drug target index (DTI) with olfactory bulb 1.69 and 2.05, vestibule 1.80 and 2.15, respectively. The results indicated that scopolamine can be absorbed directly through the olfactory mucosa into the olfactory bulb, and then transported to various brain tissue after intranasal administration, with the characteristics of brain drug delivery.
Scopolamine attenuates auditory cortex response
Published in Acta Oto-Laryngologica, 2015
Anchun Deng, Xiaojun Liang, Yuchen Sun, Yanghong Xiang, Junjie Yang, Jingjing Yan, Wei Sun
Conclusion: Scopolamine, a tropane alkaloid drug that mainly acts as an antagonist of muscarinic acetylcholine receptors, was found to reduce the local field potentials (LFP) of auditory cortex (AC) evoked by tone and gap-offsets whose effects may compensate the cortical hyperexcitability related to tinnitus. Objective: To study the effects of scopolamine on the AC and the inferior colliculus (IC) of awake rats in order to understand scopolamine’s effect on tinnitus and gap detection. Method: Silent gaps (duration varied from 2–100 ms) embedded in otherwise continuous noise were used to elicit AC and IC response. Gap evoked AC and IC field potentials were recorded from awake rats before and after treatment of scopolamine (3 mg/kg, i.m.). Results: Acute injection of scopolamine (3 mg/kg, i.m.) induced a significant reduction of the AC response, but not the IC response, to the offset of the gaps embedded in white noise. The results suggest that scopolamine may reduce AC neural synchrony.
Cocaine Addiction Treatment and Home Remedies: Use of the Scopolamine Transdermal Patch
Published in Substance Use & Misuse, 2014
Cristiana Gambelunghe, Mauro Bacci, Kyriaki Aroni, Filomena De Falco, Emira Maria Ayroldi
Recently, there has been an enormous increase in the number of people seeking treatment for cocaine addiction. Fifteen male cocaine users aged 20–30 years who requested hair analysis from our forensic toxicology laboratory (Perugia, Italy) from March to June 2012, reported using scopolamine without medical supervision to reduce the anxiety associated with cocaine withdrawal. Self-reports were verified with the results obtained from the hair analysis. We discuss whether the use of scopolamine in cocaine abusers could be supported by a neurobiological and pharmacological point of view.
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