Use of Low Dose Olanzapine for the Control of Nausea and Vomiting in Patients Receiving Highly Emetogenic Chemotherapy in a Rural Medical College in Etawah District, Uttar Pradesh, India

BACKGROUND Chemotherapy-induced nausea and vomiting (CINV) is a frequent and feared adverse effect of cancer chemotherapy. International guidelines recommend combinations of 5-hydroxytryptamine type 3 (5-HT3) receptor antagonists, dexamethasone, and/or neurokinin-1 (NK1) receptor antagonists for the control of CINV in patients receiving highly emetogenic chemotherapy (HEC) as a part of their treatment. Even though, nausea in delayed period is less controlled and poses a major concern for these patients. METHODS This open label, prospective study was conducted in a rural medical college in Etawah District in Uttar Pradesh, India from November 2017 to November 2018 over a period of 1 year to observe the efficacy of low dose (5 mg OD) olanzapine in combination with standard anti-emetic regimen for the prevention of CINV. Olanzapine is a food and drug administration (FDA) approved antipsychotic drug that has anti-emetic activity and has shown to improve CINV. Low dose olanzapine along with a standard combination of ondansetron, dexamethasone and aprepitant was given to patients receiving highly emetogenic chemotherapy (Cisplatin >70 mg/m2 or doxorubicin-cyclophosphamide combination). CINV was assessed using common toxicity criteria of adverse events (CTCAE) version 5.0. RESULTS Complete response to nausea was observed in 90.90 %, 60.60 % and 54.54 % in acute, delayed and overall period respectively. Complete response to vomiting was observed in 96.96 %, 69.69 % and 66.66 % in acute, delayed and overall period respectively. Complete response to Grade-2 (or above) nausea was observed in 96.96 %, 93.93 % and 90.90 % in acute, delayed and overall period, respectively. Daytime Grade -3 somnolence which was seen in 2/33 patients (6.06 %) was attributable to olanzapine. Patients receiving olanzapine were more likely to have complete response of nausea and emesis in the early, late, and overall assessment periods especially of higher grade (G2 and G3). CONCLUSIONS The authors concluded that low dose olanzapine 5 mg OD combined with an NK1- receptor antagonist, a 5-HT3–receptor antagonist, and dexamethasone is safe and efficacious in the prevention of CINV in patients receiving HEC. KEYWORDS Olanzapine, Low Dose, CINV, HEC

NK1 antagonists attenuate tau phosphorylation after blast and repeated concussive injury

Exposure to repeated concussive traumatic brain injury (TBI) and to blast-induced TBI has been associated with the potential development of the neurodegenerative condition known as chronic traumatic encephalopathy (CTE). CTE is characterized by the accumulation of hyperphosphorylated tau protein, with the resultant tau tangles thought to initiate the cognitive and behavioral manifestations that appear as the condition progresses. However, the mechanisms linking concussive and blast TBI with tau hyperphosphorylation are unknown. Here we show that single moderate TBI, repeated concussive TBI and blast-induced mild TBI all result in hyperphosphorylation of tau via a substance P mediated mechanism. Post-injury administration of a substance P, NK1 receptor antagonist attenuated the injury-induced phosphorylation of tau by modulating the activity of several key kinases including Akt, ERK1/2 and JNK, and was associated with improvement in neurological outcome. We also demonstrate that inhibition of the TRPV1 mechanoreceptor, which is linked to substance P release, attenuated injury-associated tau hyperphosphorylation, but only when it was administered prior to injury. Our results demonstrate that TBI-mediated stimulation of brain mechanoreceptors is associated with substance P release and consequent tau hyperphosphorylation, with administration of an NK1 receptor antagonist attenuating tau phosphorylation and associated neurological deficits. NK1 antagonists may thus represent a pharmacological approach to attenuate the potential development of CTE following concussive and blast TBI.

Medial septum neurokinin- and somatostatin-sensitive mechanisms mediate sensorimotor and nociceptive behaviours

The forebrain medial septum (MS), implicated in affective-motivational behaviours, is enriched in substance P (SP) sensitive neurokinin-1 receptors (NK1R) and somatostatin (SST) receptors (SSTR) that are located almost exclusively on cholinergic and GABAergic neurons, respectively. However, the physiological function of these receptors is poorly understood. This study characterized the actions of intraseptal SP on electrophysiological indices of septo-hippocampal activation, then utilised NK1 receptor antagonist, L-733,060, and SST to investigate the physiological role of endogenous neurotransmission at NK1R, and SST-sensitive mechanisms, in novel open field and formalin test of inflammatory pain. The findings showed that neurotransmission at NK1R mediates formalin-induced electrophysiological responses in the septo-hippocampus in anaesthetized and behaving animals. Furthermore, parallel NK1R- and SST-sensitive mechanisms affect different aspects of animal behaviours in both tests, collectively modulating attention and habituation in open field and driving formalin-induced nociception. This brings out a newer peptidergic dimension of septal physiology in nociception.

Endokinin A/B stimulates rat gastric motility through myogenic NK1 receptors located in the fundus

Endokinin A/B (EKA/B), the common C-terminal decapeptide in endokinins A and B, is a preferred ligand of the NK1 receptor and regulates pain and itch. The study focused on the effects of EKA/B on rat gastric motility in vivo and in vitro. Gastric emptying was measured to evaluate gastric motility in vivo. Intragastric pressure and the contraction of gastric muscle strips were measured to evaluate gastric motility in vitro. Moreover, various neural blocking agents and neurokinin receptor antagonists were applied to explore the mechanisms. TAC4 and TACR1 mRNAs were expressed throughout rat stomach. EKA/B promoted gastric emptying by intraperitoneal injection in vivo. Correspondingly, EKA/B also increased intragastric pressure in vitro. Additionally, EKA/B contracted the gastric muscle strips from the fundus but not from the corpus or antrum. Further studies revealed that the contraction induced by EKA/B on muscle strips from the fundus could be significantly reduced by NK1 receptor antagonist SR140333 but not by NK2 receptor antagonist, NK3 receptor antagonist, or the neural blocking agents used. Our results suggested that EKA/B might stimulate gastric motility mainly through the direct activation of myogenic NK1 receptors located in the fundus.

Motion Sifnos: A randomized, double-blind, placebo-controlled study demonstrating the effectiveness of tradipitant in the treatment of motion sickness

BackgroundNovel therapies are needed for the treatment of motion sickness given the inadequate relief, and bothersome and dangerous adverse effects of currently approved therapies. Neurokinin-1 (NK1) receptor antagonists have the potential to be effective in improving the symptoms of motion sickness, given the involvement of Substance P in nauseogenic and emetic pathways and the expression of NK1 receptors in the gastrointestinal system. Here, we evaluated the efficacy of tradipitant, a novel NK1 receptor antagonist, in preventing motion sickness in variable sea conditions.MethodsA total of 126 adults participated in the Motion Sifnos Study. Groups of participants were assigned to one of seven boat trips lasting approximately four hours on the Pacific Ocean. Participants were randomized 1:1 to tradipitant 170 mg or placebo and completed the Motion Sickness Severity Scale (MSSS) every 30 minutes, in addition to other assessments. Severity of motion sickness was assessed with the incidence of vomiting and the MSSS.ResultsParticipants on tradipitant had a significantly lower incidence of vomiting as compared to those on placebo across all boat trips (tradipitant=17.5%, placebo=39.7%, p=0.0039). For trips exposed to rough sea conditions, the difference in the incidence of vomiting between the groups was more dramatic (tradipitant=15.79%, placebo=72.22%, p=0.0009). Across these trips, motion sickness symptoms were significantly lower in the tradipitant group compared to the placebo group (tradipitant=3.19, placebo=4.57, p=0.0235).DiscussionTradipitant has the potential to be an effective therapy for the prevention of vomiting and treatment of nausea in people with motion sickness.