Diego Pinetti

Similarities and differences between chronic migraine and episodic migraine

Objective.—To quantify and characterize the similarities and the differences between chronic migraine (CM) patients with medication overuse and episodic migraine (EM) patients with only occasional analgesic use.

HPLC-DAD and HPLC-ESI-MS/MS methods for metabolite profiling of propolis extracts.

In this study, the composition of polyphenols (phenolic acids and flavonoids) in propolis extracts was investigated by HPLC-DAD and HPLC-ESI-MS/MS by comparing the performance of ion trap and triple quadrupole mass analyzers. The analyses were carried out on an Ascentis C(18) column (250mm×4.6mm I.D., 5μm), with a mobile phase composed by 0.1% formic acid in water and acetonitrile. Overall, the UV spectra, the MS and MS/MS data allowed the identification of 40 compounds. In the case of flavonoids, the triple quadrupole mass analyzer provided more collision energy if compared with the ion trap, originating product ions at best sensitivity. The HPLC method was validated in agreement with ICH guidelines: the correlation coefficients were >0.998; the limit of detection was in the range 1.6-4.6μg/ml; the recovery range was 96-105%; the intra- and inter-day %RSD values for retention times and peak areas were found to be <0.3 and 1.9%, respectively. The developed technique was applied to the analysis of hydroalcoholic extracts of propolis available on the Italian market. Although the chromatographic profile of the analyzed samples was similar, the quantitative analysis indicated that there is a great variability in the amount of the active compounds: the content of total phenolic acids ranged from 0.17 to 16.67mg/ml and the level of total flavonoids from 2.48 to 41.10mg/ml. The proposed method can be considered suitable for the phytochemical analysis of propolis extracts used in phytotherapy.

Quantitative analysis of acetylcholine in rat brain microdialysates by liquid chromatography coupled with electrospray ionization tandem mass spectrometry

A liquid chromatography tandem mass spectrometry (LC/MS/MS) method has been developed for the quantitative analysis of acetylcholine in rat brain dialysates. The separation of acetylcholine (ACh), choline (Ch), acetyl-β-methylcholine (IS) from endogenous compounds and Ringers salts was achieved with cation exchange chromatography. Optimization of chromatographic and mass spectrometry parameters were perfomed in order to improve sensitivity of the method. The limit of detection were 0.05 and 3.75 fmol on column with S/N ratio of 3:1 for ACh and Ch, respectively. The limit of quantitation (LOQ) for ACh and Ch measured in Ringers solution were 0.05 nM (0.25 fmol) and 3.75 nM (18.75 fmol), respectively at S/N ratio of 10:1. Linearity of the method has been evaluated in the concentrations range between 0.05 and 5.00 nM and 3.75 and 200 nM for ACh and Ch respectively. The correlation coefficients were 0.999 and 0.995 for ACh and Ch respectively, indicating very good linearity. The LC/MS/MS method developed has been applied to evaluate the effect of oral administration of 7-chloro-3-methyl-3,4-dihydro-2H-1,2,4-benzothiadiazine 1,1-dioxide (IDRA21), a positive modulators of AMPA receptor, on the release of ACh in the rat prefrontal cortex by microdialysis.

Pharmacokinetics of sumatriptan in non-respondent and in adverse drug reaction reporting migraine patients

Sumatriptan is a selective agonist of 5HT1 (1B/1D) receptors, which has proved to be effective and safe for the acute treatment of migraine attacks. Nevertheless, its use by migraine sufferers is still limited and some patients consider adverse reactions related to sumatriptan, especially chest symptoms, unacceptable even if not serious. Moreover, in clinical trials, almost one third and one sixth of patients, respectively, fail to experience headache relief either after oral or after subcutaneous sumatriptan administration. Our aim was to verify whether differencies in sumatriptan pharmacokinetics could explain non–response and/or adverse drug reactions. Sumatriptan levels were determined by HPLC with electrochemical detection. Pharmacokinetic parameters were calculated using a computer program (PK Solutions 2.0; non compartmental Pharmacokinetics Data Analysis). After oral administration, sumatriptan is rapidly absorbed and sometimes displays multiple peaks of plasma concentration. This “multiple peaking” gives rise to considerable inter–subject variability in the time of reaching maximum plasma concentration. Pharmacokinetic parameters of sumatriptan, both after oral and subcutaneous administration, were similar in the three patient groups. Blood pressure and heart rate did not show any significant differences between groups. Pharmacokinetic parameters and bioavailability of sumatriptan did not seem to be correlated either to the lack of efficacy or the appearance of side effects. These results could depend on the limited number of patients studied.

Simultaneous determination of pregnenolone sulphate, dehydroepiandrosterone and allopregnanolone in rat brain areas by liquid chromatography-electrospray tandem mass spectrometry.

Neurosteroids (NSs) are well known modulators of neuronal activity and by binding to different neuronal receptors are responsible for a broad spectrum of biological and pathophysiological conditions. Here, a sensitive liquid chromatographic-electrospray ionization-tandem mass spectrometric method (LC-ESI-MS/MS) has been developed and validated for the simultaneous determination in rat brain areas of three NSs, i.e. pregnenolone sulphate (PS), dehydroepiandrosterone (DHEA) and allopregnanolone (AP). NSs were extracted with methanol-formic acid, purified by Hybrid-SPE cartridges and subjected to LC-ESI-MS/MS without any preliminary derivatization or deconjugation procedure. Quantitation was performed by multiple reaction monitoring mode with the internal standard method, using deuterium-labelled analogues of the analyzed NSs. The proposed method provided for the first time a direct quantitative determination of PS without hydrolysis; in particular, PS concentrations were found significantly (p<0.01) higher in hippocampus, the brain area associated primarily with memory, than in cortical tissue of control rats, suggesting the important role of this NS in the process of memory formation. The developed method could be successfully applied to quantify simultaneously PS, DHEA and AP levels in brain tissue in order to study their changes during various neurodegenerative diseases and to investigate the role of PS in the brain.

A pilot study on the efficacy, pharmacokinetics and safety of atazanavir in patients with end-stage liver disease

OBJECTIVES Antiretroviral combinations including atazanavir are currently not recommended in HIV-infected patients with end-stage liver disease (ESLD). The objective of our study was to evaluate efficacy, pharmacokinetics and safety of unboosted atazanavir in HIV-infected patients with ESLD screened for orthotopic liver transplantation (OLT(x)). Patients and methods Single-arm, 24 week pilot study. Atazanavir-naive patients undergoing highly active antiretroviral therapy were switched to atazanavir 400 mg/day plus two non-thymidine nucleoside reverse transcriptase inhibitors. Results Fifteen patients (10 males and 5 females) were included. In the study period, 2 patients were transplanted and 10 completed 24 weeks of atazanavir treatment. Median area under the concentration-time curve at week 4 was 19 211 ng.h/mL (IQR = 8959-27 500). At week 24, median atazanavir trough concentrations (C(trough)) per patient calculated across the study were above the minimum effective concentration (MEC = 100 ng/mL) in 8 of 10 subjects. Atazanavir C(trough) time-point values were always above the MEC in five patients. The other three subjects experienced only one determination below the MEC, with median atazanavir C(trough) levels across the study being above the MEC in two of them. At 8 of 11 time-points when atazanavir and proton pump inhibitors (PPIs) were co-administered and at 16 of 19 time-points in which patients had a concomitant tenofovir association, atazanavir C(trough) was above the MEC. Conclusions Unboosted atazanavir showed a favourable pharmacokinetic profile and was able to maintain or gain immuno-virological eligibility for OLT(x) in all patients. Limited biochemical toxicities (including unconjugated hyperbilirubinaemia) and allowance of concomitant administration of tenofovir and PPIs were observed.

Differential dose adjustments of immunosuppressants after resuming boosted versus unboosted HIV-protease inhibitors postliver transplant.

Pharmacokinetic (PK) interactions between protease inhibitors (PIs) and immunosuppressive agents (IS) are critical elements in the management of HIV‐infected patients who undergo liver transplantation (LTx). The primary objective of this study was to evaluate the decreases in IS dosages necessary to maintain an appropriate therapeutic window (TW) after initiating PI‐based antiretroviral therapy regimens post‐LTx. Single‐center, PK cross‐sectional study of consecutive HIV‐infected adult patients who underwent LTx was done. Blood trough concentrations (Ct) of IS were obtained using a commercial MEIA test; plasma Ct of PIs were measured using HPLC. Twelve consecutive HIV‐infected adult patients (11 males, 1 female) were enrolled. More rapid increases in IS plasma Ct were observed 48 h after initiating ritonavir (RTV)‐boosted PI therapy post‐LTx than when using unboosted PIs. Seven patients developed acute renal failure. The median fold decrease in IS dosages required to regain IS concentrations that were in the TW was 7.5 (range 6–14) after resuming boosted PIs and 2.9 (range 2–4) after unboosted PIs. The overall median time necessary to reach IS TW after dose adjustment was 3.5 days (range 0–15). Unboosted PIs exhibited lesser PK interactions with IS than did RTV‐boosted PIs and were thus more amenable to use in the post‐LTx setting.

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.

Efficacy and Safety of Atazanavir in Patients with End-Stage Liver Disease

Background:No data are available on the use of atazanavir (ATV) in patients with end-stage liver disease (ESLD), and guidelines discourage its use in this setting. The objective of our study was to evaluate the efficacy and safety of unboosted ATV in patients infected with HIV and suffering from ESLD who had been screened for orthotopic liver transplantation (OLTx).Patients and Methods:This was a single-arm, 24-week pilot study. Atazanavir-naïve patients undergoing a highly active antiretroviral therapy were switched to ATV 400 mg daily plus two non-thymidine nucleoside reverse transcriptase inhibitors.Results:Fifteen patients (ten males and five females, age range 36–59 years) were enrolled in the study. Of these, 11 (73%) had a baseline CD4 cell count > 200 μl–1, and 12 had undetectable plasma HIV-RNA. 12 subjects (80%) were able to remain on ATV until week 24 (n = 10) or transplantation (n = 2). At the end of the study, the median CD4 cell count was 340 μl–1 , and nine of the ten patients had undetectable RNA. During the study period, two patients received a transplant, two died of intracerebral hemorrhage and lactic acidosis, respectively, and one discontinued ATV. Among the ten patients completing the 24-week study, no significant changes from baseline were observed for most of the liver function markers, with the exception of unconjugated bilirubin (from 1.15 mg/dl to 1.32 mg/dl, p = 0.047).Conclusions:Unboosted ATV treatment did not worsen liver disease and was able to maintain or gain immunovirological eligibility for OLTx in all patients, with a limited effect on unconjugated bilirubin. These results suggest that ATV is an easy-to-use drug in patients with ESLD.

Pharmacokinetics and interactions of headache medications, part II: prophylactic treatments.

The present part II review highlights pharmacokinetic drug–drug interactions (excluding those of minor severity) of medications used in prophylactic treatment of the main primary headaches (migraine, tension-type and cluster headache). The principles of pharmacokinetics and metabolism, and the interactions of medications for acute treatment are examined in part I. The overall goal of this series of two reviews is to increase the awareness of physicians, primary care providers and specialists regarding pharmacokinetic drug–drug interactions (DDIs) of headache medications. The aim of prophylactic treatment is to reduce the frequency of headache attacks using β-blockers, calcium-channel blockers, antidepressants, antiepileptics, lithium, serotonin antagonists, corticosteroids and muscle relaxants, which must be taken daily for long periods. During treatment the patient often continues to take symptomatic drugs for the attack, and may need other medications for associated or new-onset illnesses. DDIs can, therefore, occur. As a whole, DDIs of clinical relevance concerning prophylactic drugs are a limited number. Their effects can be prevented by starting the treatment with low dosages, which should be gradually increased depending on response and side effects, while frequently monitoring the patient and plasma levels of other possible coadministered drugs with a narrow therapeutic range. Most headache medications are substrates of CYP2D6 (e.g., β-blockers, antidepressants) or CYP3A4 (e.g., calcium-channel blockers, selective serotonin re-uptake inhibitors, corticosteroids). The inducers and, especially, the inhibitors of these isoenzymes should be carefully coadministered.