Oral CBD-rich Cannabis Induces Clinical but Not Endoscopic Response in Patients with Crohn's Disease, a Randomised Controlled Trial.

AIMS: Despite reports that medical cannabis improves symptoms in Crohn's disease [CD], controlled studies evaluating disease response are lacking. This study assessed the effect of cannabidiol [CBD]-rich cannabis oil for induction of remission in CD. METHODS: In a double-blind, randomised, placebo-controlled, single-centre trial, patients received orally either cannabis oil containing160/40 mg/ml cannabidiol/tetrahydrocannabinol [CBD/THC] or placebo for 8 weeks. Disease parameters, including the CD activity index [CDAI], and simple endoscopic score for CD [SES-CD], were assessed before and after treatment. In a subgroup of patients, blood samples were collected for CBD and THC plasma levels. RESULTS: The study included 56 patients, age 34.5 ± 11 years, men/women 30/26 [54/46%],30 in cannabis and 26 in placebo groups. CDAI at recruitment and after 8 weeks was 282 (interquartile range [IQR] 243-342) and 166 [IQR 82-226], and 264 [IQR 234-320] and 237 [IQR 121-271] [p <0.05] in the cannabis and placebo groups, respectively. Median quality of life [QOL] score improved from 74 for both groups at baseline to 91 [IQR 85-102] and 75 [IQR 69-88] after 8 weeks in the cannabis and placebo groups, respectively [p = 0.004]. SES-CD was 10 [IQR 7-14] and 11 [IQR7-14], and 7 [4-14] and 8 [IQR 4-12] [p = 0.75] before and after treatment, in the cannabis and placebo groups, respectively. Inflammatory markers (C-reactive protein [CRP], calprotectin) remained unchanged. CONCLUSIONS: Eight weeks of CBD-rich cannabis treatment induced significant clinical and QOL improvement without significant changes in inflammatory parameters or endoscopic scores. The oral CBD-rich cannabis extract was well absorbed. Until further studies are available, cannabis treatment in Crohn's disease should be used only in the context of clinical trials.

The pharmacokinetics, efficacy, and safety of a novel selective-dose cannabis inhaler in patients with chronic pain: A randomized, double-blinded, placebo-controlled trial.

BACKGROUND: Precise cannabis treatment dosing remains a major challenge, leading to physicians' reluctance to prescribe medical cannabis. OBJECTIVE: To test the pharmacokinetics, analgesic effect, cognitive performance and safety effects of an innovative medical device that enables the delivery of inhaled therapeutic doses of Δ9 -Tetrahydrocannabinol (THC) in patients with chronic pain. METHODS: In a randomized, three-arms, double-blinded, placebo-controlled, cross-over trial, 27 patients received a single inhalation of Δ9 -THC: 0.5mg, 1mg, or a placebo. Δ9 -THC plasma levels were measured at baseline and up to 150-min post-inhalation. Pain intensity and safety parameters were recorded on a 10-cm visual analogue scale (VAS) at pre-defined time points. The cognitive performance was evaluated using the selective sub-tests of the Cambridge Neuropsychological Test Automated Battery (CANTAB). RESULTS: Following inhalation of 0.5 mg or 1mg, Δ9 -THC plasma Cmax  ± SD were 14.3 ± 7.7 and 33.8 ± 25.7 ng/ml. Tmax  ± SD were 3.7 ± 1.4 and 4.4 ± 2.1 min, and AUC0  â†’ infinity ±SD were 300 ± 144 and 769 ± 331 ng*min/ml, respectively. Both doses, but not the placebo, demonstrated a significant reduction in pain intensity compared with baseline and remained stable for 150-min. The 1-mg dose showed a significant pain decrease compared to the placebo. Adverse events were mostly mild and resolved spontaneously. There was no evidence of consistent impairments in cognitive performance. CONCLUSION: This feasibility trial demonstrated that a metered-dose cannabis inhaler delivered precise and low THC doses, produced a dose-dependent and safe analgesic effect in patients with neuropathic pain/ complex-regional pain syndrome (CRPS). Thus, it enables individualization of medical cannabis regimens that can be evaluated pharmacokinetically and pharmacodynamically by accepted pharmaceutical models. SIGNIFICANCE: Evidence suggests that cannabis-based medicines are an effective treatment for chronic pain in adults. The pharmacokinetics of THC varies as a function of its route of administration. Pulmonary assimilation of inhaled THC causes rapid onset of analgesia. However, currently used routes of cannabinoids delivery provide unknown doses, making it impossible to implement a pharmaceutical standard treatment plan. A novel selective-dose cannabis inhaler delivers significantly low and precise doses of THC, thus allowing the administration of inhaled cannabis-based medicines according to high pharmaceutical standards. These low doses of THC can produce safe and effective analgesia in patients with chronic pain.

The pharmacokinetics, efficacy, safety, and ease of use of a novel portable metered-dose cannabis inhaler in patients with chronic neuropathic pain: a phase 1a study.

Chronic neuropathic pain is often refractory to standard pharmacological treatments. Although growing evidence supports the use of inhaled cannabis for neuropathic pain, the lack of standard inhaled dosing plays a major obstacle in cannabis becoming a "main stream" pharmacological treatment for neuropathic pain. The objective of this study was to explore the pharmacokinetics, safety, tolerability, efficacy, and ease of use of a novel portable thermal-metered-dose inhaler (tMDI) for cannabis in a cohort of eight patients suffering from chronic neuropathic pain and on a stable analgesic regimen including medicinal cannabis. In a single-dose, open-label study, patients inhaled a single 15.1 ± 0.1 mg dose of cannabis using the Syqe Inhaler device. Blood samples for Δ(9)-tetrahydrocannabinol (THC) and 11-hydroxy-Δ(9)-THC were taken at baseline and up to 120 minutes. Pain intensity (0-10 VAS), adverse events, and satisfaction score were monitored following the inhalation. A uniform pharmacokinetic profile was exhibited across all participants (Δ(9)-THC plasma Cmax ± SD was 38 ± 10 ng/mL, Tmax ± SD was 3 ± 1 minutes, AUC0→infinity ± SD was 607 ± 200 ng·min/mL). Higher plasma Cmax increase per mg Δ(9)-THC administered (12.3 ng/mL/mg THC) and lower interindividual variability of Cmax (25.3%), compared with reported alternative modes of THC delivery, were measured. A significant 45% reduction in pain intensity was noted 20 minutes post inhalation (P = .001), turning back to baseline within 90 minutes. Tolerable, lightheadedness, lasting 15-30 minutes and requiring no intervention, was the only reported adverse event. This trial suggests the potential use of the Syqe Inhaler device as a smokeless delivery system of medicinal cannabis, producing a Δ(9)-THC pharmacokinetic profile with low interindividual variation of Cmax, achieving pharmaceutical standards for inhaled drugs.

Human biomonitoring in Israel: past, present, future.

The first human biomonitoring (HBM) studies in Israel in the 1970s and 80s focused on measuring exposure to polychlorinated biphenyls (PCBs) and organochlorine insecticides in the general population and organophosphate pesticides in agricultural workers. In the late 1990 s, a regional human biomonitoring study found differences in blood lead levels in children from Israel, Jordan, and the Palestinian Authority. Taken together with data on time trends in lead emissions in Israel, the study indicated the benefits from phasing out of leaded gasoline. More recently, a pilot study in pregnant women in Jerusalem, conducted in collaboration with the US-CDC, found widespread exposure to phthalates, organophosphate pesticides, and the carbamate bendiocarb. Creatinine-adjusted total dimethyl (DM) metabolite concentrations were between 4 and 6 times higher than populations of pregnant women in the United States. The Israel Ministry of Health is currently collaborating with the Hebrew University of Jerusalem and Al Quds University to study exposures to phthalates and organophosphates in pregnant women in Israel and the Palestinian Authority. The Israel Ministry of Health has also begun the first National Biomonitoring Study to measure exposures to bisphenol A, phthalates, organophosphates, polyaromatic hydrocarbons, the phytoestrogens genistein and daidzein, and cotinine in the Israeli adult population. This study is being carried out in collaboration with the University of Erlangen-Nuremberg in Germany. Until recently, HBM programs in Israel were targeted at selected occupational groups (workers potentially exposed to metals, volatile organic compounds (VOCs), and cholinesterase inhibitors) and naval divers potentially exposed to environmental contaminants. The future of HBM in Israel lies in extending such programs to measuring exposures in representative samples of the general population, increasing international collaboration in this field, developing analytical capacity and expertise, and increasing use of human biomonitoring studies in forming and evaluating environmental health policy.

Severe paramethoxymethamphetamine (PMMA) and paramethoxyamphetamine (PMA) outbreak in Israel.

CONTEXT: Paramethoxymethamphetamine (PMMA) is a hallucinogenic synthetic substituted amphetamine that was not included in the Israeli Controlled Substance Act (CSA). OBJECTIVE: To report a severe PMMA and paramethoxyamphetamine (PMA) outbreak. PATIENTS AND METHODS: The Israeli national forensic toxicology laboratory analyzes the body fluids of unnatural deaths by means of screening immunoassays and chromatographic confirmation and quantification. Samples are referred to this laboratory by the Israeli Forensic Medicine Institute and by hospitals following consultation with the Israel Poison Information Center. The forensic toxicology laboratory began determining PMMA and PMA in February 2007. In all fatal cases with a positive immunoassay screen for amphetamines, a chromatographic analysis of PMA and PMMA was performed. The laboratory and demographic data of consecutive patients in whom PMMA or PMA were detected, were collected during 1 year and subjected to descriptive analysis. RESULTS: Of 108 fatal cases with a positive screen for amphetamines, 32 were confirmed. Twenty-four of the 32 cases tested positive for PMMA and PMA--age 27 ± 5 years, 79.2% males, post mortem whole blood PMMA and PMA concentrations 0.35 ± 0.24 and 2.72 ± 1.67 mcg/mL, respectively. Co-exposures were detected in 17 (70.8%) fatalities; including methylenedioxymethamphetamine, methylenedioxyamphetamine, cocaine, cannabinoids, cathinone derivatives, ephedrine/pseudoephedrine, opiates, and ethanol. In addition, five non-fatal male cases were identified; age 32 ± 5 years, four had co-exposures to cocaine, cathinone derivatives, and cannabinoids. These findings led to the inclusion of PMMA in the CSA in July 2007, resulting in only three more fatalities in the following year. DISCUSSION: We report an outbreak of PMMA and PMA poisoning resulting in 24 fatalities, and the post mortem whole blood and urine concentrations of these two compounds. PMA was probably the result of PMMA metabolism. Stimulant co-exposures may have contributed to the severity of the poisoning. CONCLUSION: Forensic laboratory and poison center co-operation is important in identifying a new drug of abuse.

Linearity and stability of intravenous busulfan pharmacokinetics and the role of glutathione in busulfan elimination.

High-dose busulfan (Bu) is frequently used in preparative myeloablative conditioning (MAC) regimens for patients undergoing hematopoietic stem cell transplantation (HSCT). MAC and reduced-intensity conditioning (RIC) protocols for i.v. Bu infusion have been developed to achieve reliable systemic exposure while minimizing toxicity and treatment failure (relapse). The objectives of the present study were to (1) compare the pharmacokinetics (PK) of i.v. Bu in different dosing protocols, (2) compare intrasubject variability of Bu PK over repeated administrations; (3) examine the effect of concomitant administration of fludarabine on Bu PK, and (4) examine the effect of plasma concentrations of glutathione (GSH), the cosubstrate in Bu metabolism, on Bu clearance. We studied Bu PK twice in each of 46 HSCT patients (after the first and then after the middle dose of the treatment cycle) receiving one of 4 dosing protocols, 2 MAC (cumulative dose, 12.8 mg/kg) and 2 RIC (cumulative dose, 6.4 mg/kg), with daily doses administered either as an individual infusion (3.2 mg/kg) or as 4 infusions of 0.8 mg/kg each. Blood samples were obtained for 6-24 hours after dosing for measurement of Bu plasma concentrations. PK parameters were estimated using compartmental analyses. In a subgroup of patients (n = 14), GSH blood concentrations were determined before Bu administration. Dose- and weight-corrected Bu PK parameters (clearance, 0.173 ± 0.051 L/hour · kg; volume of distribution, 0.71 ± 0.17 L/kg; half-life time, 3.0 ± 0.7 hours) did not differ among treatment protocols (all P >.14) and remained stable between the first and mid-cycle doses. Fludarabine did not affect Bu PK. Blood GSH concentrations before Bu dosing were positively correlated with Bu clearance (adjusted R(2) = 0.45; P = .009). Our data indicate that Bu PK parameters are linear, stable, and predictable in different i.v. protocols and are unaffected by coadministration of fludarabine. Differences in whole blood GSH might contribute to variability in Bu clearance.

Warfarin and vitamin K intake in the era of pharmacogenetics.

The considerable variability in the warfarin dose-response relationship between individuals, is explained mainly by genetic variation in its major metabolic (CYP2C9) and target (VKORC1) enzymes. Despite the predominance of pharmacogenetics, environmental factors also affect the pharmacokinetics and pharmacodynamics of warfarin, and are often overlooked. Among these factors, dietary and supplemental vitamin K consumption is a controllable contributor to within-, and between-patient variability of warfarin sensitivity. In this commentary we review the current role of vitamin K in warfarin anticoagulation therapy, with emphasis on the following: 1 The effect of dietary and supplemental vitamin K on warfarin anticoagulation, beyond the impact of genetic variability in CYP2C9 and VKORC1. We deal separately with the effects of vitamin K on warfarin dose requirements during the induction of therapy, as opposed to its effect on stability of anticoagulation control during maintenance therapy. 2 The role of vitamin K supplementation in warfarin treated patients with vitamin K deficiency as well as in patients with unstable warfarin anticoagulation, and 3 The role of therapeutic vitamin K in cases of warfarin over-anticoagulation.

10 years of oral anticoagulant pharmacogenomics: what difference will it make? A critical appraisal.

Since the first report on warfarin pharmacogenetics in 1999, genetic variants have emerged as an important predictor of warfarin maintenance doses before therapy is initiated, raising expectations of greatly improved clinical outcomes. However, much of the information on warfarin sensitivity conveyed by genetic variants is captured by early international normalized ratio values traditionally used to guide dose titration. Thus, inclusion of early international normalized ratios in prediction models reduces the contribution of genetics. Moreover, in large population cohorts, genetics explained only 20-30% of variance in warfarin doses. Finally, even pharmacogenetic prediction models did not predict doses reliably in the majority of at-risk patients with warfarin requirements at the low or high end of the dose range. Currently, the clinical utility and cost-effectiveness of pharmacogenetic-based dosing are being assessed in large prospective trials in various settings. In the interim, enthusiasm for warfarin pharmacogenetics should not supersede strict adherence to traditional measures used to optimize coumarin anticoagulation.

Hepatitis C, B, and human immunodeficiency virus infections in illicit drug users in Israel: prevalence and risk factors.

BACKGROUND: Infections with blood-borne viruses are a major health problem among illicit drug users. There is little information about infection rates and risk factors for hepatitis virus B, C or the human immunodeficiency virus in drug users in Israel. OBJECTIVES: To determine the prevalence of HCV, HBV and HIV infections in a large cohort of drug users in Israel; to compare rates of HCV, HBV and HIV between injecting versus non-injecting drug users and between different countries of origin; and to identify risk factors for HCV among illicit drug users. METHODS: We conducted a cross-sectional study using an interviewer-administered questionnaire and serological screening for HCV, HBV and HIV in 1443 consecutive drug users diagnosed at the Israeli National Center for Diagnosis of Drug Addicts between January 2003 and December 2005. RESULTS: Fourteen (0.9%), 51 (3.5%) and 515 (35.7%) subjects tested positive for HIV, HBV and HCV, respectively. All three infections (HIV, HBV and HCV) were significantly more common among injecting drug users and immigrants from the former Soviet Union and other East European countries compared to native Israelis. Multivariate analysis showed that HCV infection was associated with age (> 40 years) (OR=2.06, 95% CI 1.40-3.03), immigration from East European countries and the former Soviet Union (OR=4.54, 95% CI 3.28-6.28), and injecting drug use (OR=16.44, 95% CI 10.79-25.05). CONCLUSIONS: HIV, HBV and HCV prevalence among drug users in Israel is significantly lower than in North America and West Europe. Risk factors for HCV infection in this population include injecting drug use, older age, and immigration from the former Soviet Union.

A coding VKORC1 Asp36Tyr polymorphism predisposes to warfarin resistance.

CYP2C9 and VKORC1 genetic variants are associated with low and intermediate warfarin dose requirements, but markers of high doses are less well characterized. We analyzed the VKORC1 coding sequence and known CYP2C9 and VKORC1 polymorphisms in 15 selected warfarin-resistant (dose, 80 to 185 mg/wk) and 8 warfarin-sensitive patients (7 to 13 mg/wk) and 99 unselected controls (8 to 105 mg/wk). We identified a coding VKORC1 Asp36Tyr polymorphism in 7 of 15 resistant compared with 0 of 8 sensitive patients (P = .026) Carriers of Asp36Tyr in the control group (8 of 99) required significantly higher warfarin doses of 80.9 +/- 10.1 mg/wk compared with 42.7 +/- 7.5 mg/wk in noncarriers (F = 9.79, P = .002). Asp36Tyr was significantly associated with doses of more than 70 mg/wk (odds ratio, 13.0; 95% confidence limit, 1.3 to 124.2), while doses of 20 to 70 mg/wk were associated with Asp36Tyr (partial r(2) = .11; P = .004), CYP2C9*2 and *3 (r(2) = .08; P = .01), and VKORC1*2 and *3 markers (r(2) = .05; P = .05). All Asp36Tyr carriers also had VKORC1*1 tag-single nucleotide polymorphisms (tag-SNPs) indicating a new haplotype. Asp36Tyr was common in Jewish ethnic groups of Ethiopian (15%) and Ashkenazi (4%) origin. We suggest that Asp36Tyr is a new marker of the high end of the warfarin dosing range.

Combined genetic profiles of components and regulators of the vitamin K-dependent gamma-carboxylation system affect individual sensitivity to warfarin.

We examined the influence of combined genotypes on interindividual variability in warfarin dose-response. In 100 anticoagulated patients we quantified the effects of polymorphisms in: CYP2C9, VKORC1, calumenin (CALU), gamma-glutamyl carboxylase (GGCX) and microsomal epoxide hydrolase (EPHX1) on warfarin dose requirements. The G(1542)C VKORC1 polymorphism was associated with decreased warfarin doses in the hetero- and homozygous mutant patients (21% and 50% lower, respectively; p < 0.0001). Warfarin daily dose was predominantly determined by VKORC1 and CYP2C9 genotypes (partial r(2) = 0.21; 0.20, respectively). Together with age and body weight, these two genotypes explained 63% of the dose variance. A single patient, homozygous for G(11)A CALU mutant allele, required an exceptionally high warfarin dose (20 mg/day) and the prevalence of heterozygous (11)A allele carriers in the upper 10(th) dose percentile was significantly higher (0.27 vs. 0.18, p < 0.02). Combined genotype analysis revealed that CYP2C9 andVKORC1 wild type and CALU mutant patients required the highest warfarin doses (7.8 +/- 1.5mg/day; n = 9) as compared to the CYP2C9 and VKORC1 mutant and CALU wild type genotypes (2.8 +/- 0.3 mg/day; n = 18; p < 0.01). The odds ratio for doses <3mg/day was 5.9 (1.9-18.4) for this genotype. Compound genetic profiles comprising VKORC1, CALU and CYP2C9 improve categorization of individual warfarin dose requirements in more than 25% of patients at steady-state anticoagulation.

Common genetic variants of microsomal epoxide hydrolase affect warfarin dose requirements beyond the effect of cytochrome P450 2C9.

BACKGROUND: Warfarin dose response is partially explained by the polymorphisms in the cytochrome P450 (CYP) 2C9 gene, affecting S -warfarin clearance, as well as by age and body weight. We examined the influence on warfarin dose requirements of candidate genes encoding microsomal epoxide hydrolase (mEH), as well as glutathione S -transferase A1 (GSTA1) components of vitamin K epoxide reductase and the gamma-glutamylcarboxylase (GGCX) gene. METHODS: We studied the effects of CYP2C9, mEH, GSTA1, and GGCX genotypes on warfarin maintenance doses, accounting for age, weight, vitamin K plasma concentrations and concurrent medications, in 100 patients undergoing therapeutic anticoagulation. RESULTS: Allele frequencies were 76.5%, 12.5%, and 11% for CYP2C9*1 , *2 , and *3 , respectively; 75% and 25% for mEH T 612 C; 75.8% and 24.2% for mEH A 691 G; 73.5% and 26.5% for GSTA1 T 631 G; and 70.5% and 29.5% for GGCX G 8762 A. Warfarin doses differed among the CYP2C9 ( 2C9*1 , 2C9*2 , and 2C9*3 ) genotype groups: 6.3 +/- 1.9 mg/d, 5.3 +/- 1.8 mg/d, and 3.8 +/- 1.7 mg/d, respectively (F = 4.83, P < .01). There were no differences in any of the other genotype groups. Among the 62 wild-type CYP2C9 patients, variant mEH T 612 C homozygotes required higher doses than heterozygotes and wild-type patients (7.5 +/- 2.9 mg/d, 6.5 +/- 4.2 mg/d, and 6.0 +/- 2.6 mg/d, respectively [F = 3.57, P = .03]). The odds ratio for requiring greater than 7 mg/d in variant mEH T 612 C patients versus wild-type patients was 3.14 (95% confidence interval, 1.47-6.67), accounting for CYP2C9. CONCLUSIONS: Variant mEH T 612 C genotypes are associated with warfarin doses of greater than 50 mg/wk beyond the effect of CYP2C9.

Over-the-counter vitamin K1-containing multivitamin supplements disrupt warfarin anticoagulation in vitamin K1-depleted patients. A prospective, controlled trial.

Most multivitamin supplements contain far less vitamin K(1) than thought to affect warfarin anticoagulation. Having described 3 patients with multivitamin-warfarin interactions, we hypothesized that vitamin K(1)-depleted patients are sensitive to even small increments. Therefore, we compared the effect of a vitamin K(1)-containing multivitamin on warfarin anticoagulation between patients with low versus normal vitamin K(1) status. We screened 102 warfarin-treated patients and recruited nine with "low" (< 1.5 mcg/L, 10(th) percentile) (group 1) and 7 with "normal" (>4.5 mcg/L, median) (group 2) total vitamin K(1) plasma levels (vitamin K(1) + vitamin K(1) 2,3-epoxide). Patients received one multivitamin tablet containing 25 mcg of vitamin K(1) daily, for 4 weeks (period 1). A predefined algorithm was used to adjust warfarin doses if the INR was outside the therapeutic range. Patients requiring warfarin increments were then switched to 4 weeks of a vitamin K(1)-free multivitamin supplement (period 2). During period 1, subtherapeutic INRs occurred in 9/9 and 1/7 patients in group 1 and 2, respectively (p <0.001). In group 1, INR decreased by a median of 0.51 (p <0.01), and warfarin dose had to be raised by 5.3% (p <0.01), whereas INR and warfarin dose did not change significantly in group 2. During period 2 (7 patients), there were trends towards decreased total vitamin K(1) and rising INRs associated with significantly lower warfarin doses. We conclude that vitamin K(1)-containing multivitamins reduce INR in patients with low vitamin K(1) status. Our study suggests that vitamin K-depleted patients are sensitive to even small changes in vitamin K(1) intake.

Suppression of gamma-melanocyte-stimulating hormone secretion is accompanied by salt-sensitive hypertension in the rat.

Gamma-melanocyte-stimulating hormone (gamma-MSH) is a natriuretic peptide derived from proopiomelanocortin (POMC) in the pituitary neurointermediate lobe (NIL); its plasma concentration in rats doubles after ingestion of a high (HSD; 8% NaCl) compared with a low sodium diet (LSD; 0.07%). Because NIL function is regulated through dopaminergic pathways, we asked whether dopaminergic stimulation with bromocriptine (5 mg/kg IP daily for 1 week) or inhibition with haloperidol (5 mg/kg IP for 1 week) alters the gamma-MSH response to a HSD. In vehicle-treated rats, plasma gamma-MSH and NIL gamma-MSH content on the HSD were both markedly elevated over values in rats on the LSD (P<0.001); no difference in mean arterial pressure (MAP) occurred. In haloperidol-treated rats on the LSD, both plasma gamma-MSH and NIL gamma-MSH content were greater than in vehicle-treated rats (P<0.05) and did not increase further on the HSD; MAP was also no different. In bromocriptine-treated rats, neither plasma gamma-MSH nor NIL gamma-MSH content increased on the HSD versus LSD, and MAP was markedly elevated on the HSD (132+/-3 versus 106+/-3 mm Hg, P<0.001). Intravenous infusion of gamma-MSH (0.4 pmol/min) to bromocriptine-treated rats on the HSD restored plasma gamma-MSH concentration to a level appropriate for the HSD and lowered MAP from 131+/-6 to 108+/-5 mm Hg (P<0.01). These results demonstrate that the increases in NIL content and plasma concentration of gamma-MSH normally occurring during ingestion of the HSD are prevented by dopaminergic suppression of NIL function. This results in deficiency of gamma-MSH on the HSD and is accompanied by elevated blood pressure, which is corrected by infusion of the peptide. gamma-MSH may be an important component in the normal response to a HSD; interruption of this response leads to salt-sensitive hypertension.

Multivitamin supplements may affect warfarin anticoagulation in susceptible patients.

OBJECTIVE: To report an interaction of a multivitamin preparation containing small amounts of vitamin K(1) (25 microg) with warfarin in a case series and to assess the prevalence of vitamin K(1) deficiency in ambulatory anticoagulated patients. CASE SUMMARIES: We describe 3 patients whose anticoagulation was stabilized with warfarin in whom initiation or cessation of a self-prescribed multivitamin supplement delivering 25 microg of vitamin K(1) daily was associated with an otherwise unexplained significant fall or rise in international normalized ratio (INR), respectively, with major thrombosis or hemorrhage in 2. This interaction was rated probable on the Naranjo probability scale. Suspecting vitamin K(1) deficiency as an explanation for this oversensitivity, we assessed the prevalence of vitamin K(1) deficiency in our clinic by determining plasma vitamin K(1) levels in 179 stable consecutive patients, finding very low levels (<0.1 ng/mL) in 22 of 179 (12%). DISCUSSION: Vitamin K(1) supplements of 25 microg daily are far below the dose thought to affect anticoagulant control. We hypothesize that, in our patients, unsuspected vitamin K(1) deficiency caused an oversensitivity to small vitamin K(1) supplements. In patients with low vitamin K(1) status, even such low doses represent a significant increment in daily intake, thus lowering the sensitivity to warfarin. Our analysis suggests that low vitamin K(1) status exists in a small, but important, minority of ambulatory patients undergoing anticoagulation. CONCLUSIONS: Clinicians should instruct anticoagulated patients to report the use of multivitamin supplements and inquire about it in cases of unexplained INR changes.

Do therapeutic doses of acarbose alter the pharmacokinetics of digoxin?

BACKGROUND: Acarbose has become an important adjuvant therapy for diabetic patients. Many of these patients are also treated with digoxin for congestive heart failure or chronic atrial fibrillation. OBJECTIVE: To evaluate a possible drug interaction between acarbose and digoxin. METHODS: An open-label, analyst-blind, randomized, crossover, two-period study was conducted in 11 healthy subjects. In period I, each subject received one single oral dose of 0.75 mg digoxin. In period II, they were given acarbose tablets, 50 mg 3 times a day for 12 days. On day 8, one hour after acarbose administration, a single oral dose of 0.75 mg digoxin was administered. The study periods were separated by a 3 week washout interval. Serum digoxin levels, over time, in the two periods were compared by standard techniques. RESULTS: There were no differences in the pharmacokinetic parameters of digoxin in the two periods, apart from a significant increase in the mean maximum serum concentration (Cmax) when digoxin was given with acarbose (5.97 compared to 4.67 g/L, P = 0.02). Simulated steady-state peak levels of digoxin (Cmax,ss) achieved with a daily dose of 0.25 mg digoxin, in the presence and absence of acarbose, were 2.89 and 2.40 g/L respectively (P = 0.05). Simulated steady-state trough (Cmin,ss) and average (Cave,ss) concentrations were similar and within the therapeutic window. CONCLUSION: There was no significant pharmacokinetic interaction between digoxin and acarbose at current therapeutic doses in the healthy volunteers. This interaction should be further studied with higher doses of acarbose and at steady-state conditions.