Pharmacol Rep
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Oxycodone is a valued opioid analgesic, which may be administered either as the first strong opioid or when other strong opioids are ineffective. In case of insufficient analgesia and/or intense adverse effects such as sedation, hallucinations and nausea/vomiting a switch from another opioid to oxycodone might be beneficial. Oxycodone is administered to opioid-naive patients with severe pain and to patients who were unsuccessfully treated with weak opioids, namely tramadol, codeine and dihydrocodeine. ⋯ Another new product that was launched recently is a combination of prolonged-release oxycodone with prolonged-release naloxone (oxycodone/naloxone tablets). The aim of this review is to outline the pharmacodynamic and pharmacokinetic properties, drug interactions, dosing rules, adverse effects, equianalgesic dose ratio with other opioids and clinical studies of oxycodone in patients with cancer pain. The potential role of oxycodone/naloxone in chronic pain management and its impact on the bowel function is also discussed.
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Randomized Controlled Trial
Pentazocine pretreatment suppresses fentanyl-induced cough.
This study evaluated the effect of pentazocine pretreatment on fentanyl-induced cough. With ethics committee approval, 277 ASA I-II patients, aged between 19 and 63 years, undergoing various elective surgeries during general anesthesia, were enrolled in this prospective, randomized, double-blind, placebo-controlled clinical trial. All patients were randomly assigned to one of three groups. ⋯ The incidence of cough was 0%, 22.6% and 4.3% in Group I, Group II and Group III, respectively. There was no significant difference in SpO(2) for the duration of the trial among the three groups. Premedication with intravenous pentazocine can minimize the incidence of fentanyl-induced cough and has no influence on blood pressure, heart rate, and SpO(2) compared with Group II.
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Receptors for 5-HT(1A) are widely distributed throughout the basal ganglia, and their activation results in an inhibition of dopamine (DA) release. This study aimed to investigate the effect of buspirone, as a partial agonist of 5-HT(1A) receptors, on 6-hydroxydopamine (6-OHDA)-induced catalepsy in male Wistar rats. Catalepsy was induced by unilateral infusion of 6-OH-DA (6 microg/2 microl/rat) into the central region of the substantia nigra pars compacta (SNc) and assayed by the bar-test method 60, 120 and 180 min after drug administration. ⋯ The effects of buspirone (7.5 mg/kg, ip) and 8-OH-DPAT (10 microg/rat, intra-SNc) were abolished by 1-(2-methoxyphenyl)-4-[4-(2-phthalimido) butyl]piperazine hydrobromide (NAN-190; 10 microg/rat, intra-SNc), a 5-HT(1A) receptor antagonist. Our study indicates that buspirone improves catalepsy in a 6-OHDA-induced animal model of Parkinson's disease through activation of nigral 5-HT(1A) receptors. However, further investigations should be undertaken to clarify the exact mechanism of interaction between 5-HT(1A) and DA receptors.
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Clinical trials with partial liquid ventilation demonstrate improvement in oxygenation, as well as some adverse side effects linked to the application of liquid perfluorocarbons (PFCs) during liquid ventilation. Thus, we examined the effects of systemic administration of PFC on acute lung injury (ALI) induced by lipopolysaccharide (LPS) and its effects on heme oxygenase-1 (HO-1), a compound that provides potent cytoprotection against lung injury. Rats were assigned to one of six groups (n = 8). ⋯ Furthermore, perfluorohexane increased HO-1 protein production and stimulated HO-1 activity in the lung tissue. Pre-treatment with Zinc protoporphyrin IX, an inhibitor of HO-1, decreased the protective effects of perfluorohexane in rats. In summary, systemic perfluorohexane alleviates LPS-induced lung injury in rats, and HO-1 may be involved in the mechanism of this reduction.
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Case Reports
Local pulmonary opioid network in patients with lung cancer: a putative modulator of respiratory function.
Recently, there has been growing interest in the opioid regulation of physiological respiratory function. However, evidence for a local opioid network that includes endogenous opioid peptides and their receptors is scarce. Tissue samples from patients with lung cancer were examined by immunohistochemistry to identify the components of the opioid network: beta-endorphin (END); its precursor, proopiomelanocortin (POMC); the key processing enzymes prohormone convertase 1 and 2; carboxypeptidase E; and END's corresponding opioid receptor, the mu-opioid receptor (MOR). ⋯ Furthermore, nebulized morphine improved pulmonary function parameters in advanced lung cancer. These findings provide evidence of a local opioid network in functionally important anatomical structures of the respiratory system; this network consists of all the machinery required for POMC processing into active peptides, such as END, and contains the receptors for END. Our findings indicate a need for further clinical trials to elucidate the modulatory function of peripheral endogenous opioids in the human lung.