Effects of enhancement and antagonism of 5-hydroxytryptamine activity on the influence of metoclopramide on gastric emptying

Identification of in vitro-in vivo components of Caoguo using accelerated solvent extraction combined with gas chromatography-mass spectrometry integrated with network pharmacology on indigestion

Background

Caoguo (Tsaoko Fructus), a traditional Chinese medicine, is widely used as medicine and dietary spices. Volatile components are among its important bioactive constituents used to treatment of abdominal distension and pain, but the mechanism is not clear up to now. The purpose of this study was to develop a simple, sensitive, and accurate method to analyze and identify components of Caoguo in vitro and in vivo, and further investigate the therapeutic mechanism of Caoguo on indigestion using network pharmacology.

Methods

Caoguo were extracted by accelerated solvent extraction (ASE) and n-hexane:ethyl acetate (1:1, v/v) was selected as the extraction solvent. Gas chromatography-mass spectrometry (GC-MS) was adopted to analyze and identify the volatile components in vitro and in vivo. Network pharmacology including protein-protein network construction, Gene Ontology (GO) enrichment and pathway enrichment analysis and component-target-pathway network construction was applied.

Results

By comparing the retention times and mass spectrometry data, as well as retrieving the reference literature, a total of 169 components were tentatively identified in Caoguo extract and 43 components were identified in rats plasma samples for the first time. The results of network pharmacology analysis indicated that the potential mechanism was mainly associated with regulation of lipolysis in adipocytes and serotonergic synapse signaling pathway, which might be responsible for the effect of indigestion.

Conclusions

Caoguo was first extracted by ASE and the volatile chemical components in vivo were first identified by GC-MS. Coupled with network pharmacology analysis, a network of component-target-pathway was constructed to reveal the possible mechanism of Caoguo in treatment of indigestion. This study provided a new reference method for the extraction and analysis of Caoguo, laid a chemical basis for in-depth studies on pharmacodynamics and pharmacology, and revealed an updated understanding of the therapeutic effects of Caoguo on indigestion.

Off-label prescribing patterns of antiemetics in children: a multicenter study in Italy

Acute gastroenteritis (AG) represents both the main cause of acute vomiting in children under 3 years old and a major cause of access to the emergency department. Even if several drugs may be able to reduce the emesis, the pharmacological treatment of vomiting in children remains a controversial issue, and several drugs are prescribed outside their authorized drug label with respect dosage, age, indication, or route of administration and are named as off-label. The aim of present study was to assess the off-label use of antiemetic drugs in patients less than 18 years with vomiting related to AG. This study was carried out in eight pediatric emergency departments in Italy. The following data were obtained crossing the pharmacy distribution records with emergency departments' patient data: sex and age of the patients and detailed information for each drug used (indication, dose, frequency, and route of administration). We recorded that antiemetic drugs were prescribed in every year, particularly in children up to 2 years old, and compared with both literature data and data sheet; 30 % of the administered antiemetics were used off-label. In particular, domperidone was the only antiemetic used labeled for AG treatment in pediatric patients, while metoclopramide and ondansetron have been off-label for both age and indications (i.e., AG treatment).

CONCLUSIONS

In conclusion, we documented an off-label use of antiemetics in children, and this could represents a problem of safety for the patient and a legal risk for the prescribing physician if patients have an unwanted or bad outcome from treatment.

Pharmacokinetics and interactions of headache medications, part I: introduction, pharmacokinetics, metabolism and acute treatments

Recent progress in the treatment of primary headaches has made available specific, effective and safe medications for these disorders, which are widely spread among the general population. One of the negative consequences of this undoubtedly positive progress is the risk of drug-drug interactions. This review is the first in a two-part series on pharmacokinetic drug-drug interactions of headache medications. Part I addresses acute treatments. Part II focuses on prophylactic treatments. The overall aim of this series is to increase the awareness of physicians, either primary care providers or specialists, regarding this topic. Pharmacokinetic drug-drug interactions of major severity involving acute medications are a minority among those reported in literature. The main drug combinations to avoid are: i) NSAIDs plus drugs with a narrow therapeutic range (i.e., digoxin, methotrexate, etc.); ii) sumatriptan, rizatriptan or zolmitriptan plus monoamine oxidase inhibitors; iii) substrates and inhibitors of CYP2D6 (i.e., chlorpromazine, metoclopramide, etc.) and -3A4 (i.e., ergot derivatives, eletriptan, etc.), as well as other substrates or inhibitors of the same CYP isoenzymes. The risk of having clinically significant pharmacokinetic drug-drug interactions seems to be limited in patients with low frequency headaches, but could be higher in chronic headache sufferers with medication overuse.

Evaluation of the potential pharmacokinetic interaction between almotriptan and fluoxetine in healthy volunteers

This study was designed to assess the pharmacokinetics of almotriptan, a 5HT1B/1D agonist used to treat migraine attacks, when administered in the presence and absence of fluoxetine. Healthy male (n = 3) and female (n = 11) volunteers received (1) 60 mg fluoxetine daily for 8 days and 12.5 mg almotriptan on Day 8 and (2) 12.5 mg almotriptan on Day 8, according to a two-way crossover design. Plasma and urinary almotriptan concentrations were measured by HPLC methods. Treatment effects on pharmacokinetic parameters were assessed by analysis of variance. Mean almotriptan Cmax was significantly higher following combination treatment with fluoxetine (52.5 +/- 11.9 ng/ml vs. 44.3 +/- 10.9 ng/ml, p = 0.023). Mean AUC0-infinity was not significantly affected by fluoxetine coadministration (353 +/- 55.7 ng.h/ml vs. 333 +/- 33.6 ng.h/ml, p = 0.059). Confidence interval analysis (90%) of log-transformed pharmacokinetic parameters showed that the confidence interval for AUC0-infinity was within the 80% to 125% limit for equivalence, but Cmax was not (90% CI 106%-134% of the reference mean). Adverse events were mild to moderate in intensity, and no clinically significant treatment effects on vital signs or ECGs were observed. The results show that fluoxetine has only a modest effect on almotriptan Cmax. Concomitant administration of the two drugs is well tolerated, and no adjustment of the almotriptan dose is warranted.

Efeito do tratamento da depressão sobre o esvaziamento gástrico

O esvaziamento gástrico foi medido por meio de refeição sólida marcada com 99mTc em 11 pacientes que atendiam os critérios de "depressão maior" do DSM-III-R antes e após o tratamento com fluoxetina (20 a 40mg por dia) durante nove semanas. Após o tratamento não se observou redução no tempo para o esvaziamento gástrico de metade da refeição de prova (T1/2) em relação a antes do tratamento. Pode-se, no entanto, separar os pacientes em dois subgrupos: 1) Os que exibiram resposta ao antidepressivo (redução do escore da Escala de Depressão de Hamilton >50%) e apresentaram redução significativa do T1/2 (p<0,001) e 2) Os pacientes que, sem resposta ao tratamento (redução do escore da Escala de Depressão de Hamilton £50%), não apresentaram redução do T1/2 (p>0,10). Concluímos que a alteração da velocidade do esvaziamento gástrico pode estar correlacionada à resposta ao tratamento antidepressivo e que sua redução ou aumento não pode ser atribuída à ação farmacológica da fluoxetina sobre o estômago, mas antes ao efeito da melhoria da depressão sobre a motilidade gástrica.

Role of nitric oxide in fasting gastric fundus tone and in 5-HT1 receptor-mediated relaxation of gastric fundus

Fasting gastric fundus tone is maintained by continuous cholinergic input. 5-Hydroxytryptamine-1 (5-HT1) receptor activation decreases gastric fundus tone in humans. Whether this fundus-relaxing effect is mediated via inhibition of cholinergic input or via activation of a nitrergic pathway is unknown. The aim of the present study was to determine the effect of nitrergic inhibition on feline gastric fundus tone and on 5-HT1 receptor-mediated relaxation of the fundus. Administration of Nomega-nitro-L-arginine methyl ester (L-NAME) alone caused a significant decrease of the mean baseline volume (P < 0.005), which was restored completely by addition of L-arginine. Sumatriptan caused a dose-dependent relaxation of the gastric fundus (P < 0.0005). This relaxation was inhibited by L-NAME (P < 0.02) and was restored by prior administration of L-arginine. Buspirone did not cause any change in mean baseline volume, whereas the sumatriptan-induced relaxation was not affected by prior administration of NAN-190. Our data indicate that fasting fundus tone relies not only on continuous cholinergic input but also on continuous nitrergic input, implying that fasting fundus tone is maintained by the balance of a cholinergic and nitrergic drive. Furthermore, fundus relaxation via 5-HT1 receptor activation is mediated through activation of a nitrergic pathway.

Metoclopramide increases the bioavailability of dantrolene in spinal cord injury

A study was conducted to determine the effect of metoclopramide on the disposition of dantrolene in patients with spinal cord injury (SCI) and in neurologically intact, able-bodied volunteers. Fifteen serum samples each were collected from 6 able-bodied volunteers and 13 patients with SCI (7 paraplegics, 6 quadriplegics) in a prospective, open-label, pharmacokinetic study of a single 100-mg oral dose of dantrolene. After a washout period, a single 10-mg intravenous dose of metoclopramide was given along with dantrolene to the patients with SCI only, and the study was repeated in sequential, crossover fashion. Concentrations of dantrolene were measured by a high-performance liquid chromatography (HPLC) assay. Numerical integration was used to calculate area under the curve (AUC) and mean residence time (MRT). Differences were studied using paired and two-sample, nonparametric tests, with 0.05 as the significance level. Without metoclopramide, the AUC of dantrolene was larger in able-bodied volunteers than in patients with SCI, and the MRT of dantrolene was similar both groups. When patients with SCI received metoclopramide before treatment with dantrolene, the median increase in the AUC for dantrolene was 57%, with no change in MRT. This pharmacokinetic interaction is probably attributable to augmented absorption and could alter the pharmacologic action of dantrolene. Concurrent treatment of patients with SCI with metoclopramide and dantrolene should be accompanied by careful surveillance to avoid toxicity and preserve efficacy.