Onset of action during on-demand treatment with maalox suspension or low-dose ranitidine for heartburn.

AIM: To compare the onset of action of the local antacid Maalox and the systemic H2-antagonist ranitidine, during 'on demand' ambulant treatment of a single heartburn episode, using a randomized, parallel group, double-blind, double-dummy design. METHODS: Subjects with self-perceived heartburn without known gastrointestinal disease or interfering treatments were selected with questionnaires. The study was performed unsupervised, whenever heartburn required medication. An electronic patient diary gave instructions when to take study medication, and provided visual analogue scales and five-item relief ratings for heartburn, at frequent time intervals activated by an alarm-clock. RESULTS: After a study of the natural history of heartburn and the feasibility of the study procedures in 23 patients, 49 subjects took Maalox and 45 ranitidine. Half of these experienced meaningful heartburn relief within 19 min after Maalox, and within 70 min after ranitidine. One hour after intake, the average heartburn relief score was 3.43 in the Maalox group and 3.04 in the ranitidine group (3 means 'slight improvement' and 4 'strong improvement'). Heartburn was similar in both groups after 3 h. CONCLUSIONS: Maalox provides faster relief of heartburn than ranitidine. Heartburn can be assessed frequently and reliably under ambulant conditions using an electronic patient diary.

Disagreement between bedside and laboratory activated partial thromboplastin time and international normalized ratio for various novel anticoagulants.

During studies on warfarin, heparin and various anticoagulants with novel mechanisms of action, the activated partial thromboplastin time (aPTT) and the (apparent) international normalized ratio (INR) from a bedside monitor (Coagucheck Plus(R)) were compared with laboratory assay results. Data were compared using the Bland and Altman method of comparison where systematic differences result in significant slopes of the regression line. During heparin treatment, the bedside monitor largely underestimated the aPTT (slope = -0.80). During treatment with the direct thrombin inhibitor napsagatran (slope = 0.99), the pentasaccharides Org31540/SR90107A (slope = 0.77) and SanOrg34006 (slope = 0.35), and warfarin (slope = 0.60), the bedside monitor underestimated the aPTT at lower aPTT levels, while at higher aPTT levels it overestimated the laboratory values. The bedside monitor slightly overestimated the INR during treatment with warfarin (slope = 0.33). Apparent INR was largely overestimated during treatment with Org31540/SR90107A (slope = 1.38), SanOrg34006 (slope = 0.97), Napsagatran (slope = 1.23), and recombinant tissue factor pathway inhibitor (slope = 1.48, P < 0.001 for all regression lines). These results indicate that a substantial disagreement in aPTT or (apparent) INR exists between the bedside monitor and laboratory assay during treatment with the studied 'classic' and novel anticoagulants. The amount of disagreement depended on the anticoagulant given.

Compression therapy in patients with orthostatic hypotension: a systematic review.

AIM: Orthostatic hypotension is common, especially in the elderly, and it is strongly associated with discomfort and falls. Physicians may sometimes prescribe compression therapy, but the beneficial effect of this treatment in orthostatic hypotension is unclear. The aim of this review was to summarise all available evidence on the effect of four different levels of compression therapy in the treatment of orthostatic hypotension: knee-length, thigh-length, full-length and abdominal compression only. METHODS: A systematic search was performed in PubMed, Embase and Cochrane databases. RESULTS: A literature search identified 1232 reports; 11 publications were selected for inclusion in this review. The quality of studies was heterogenous and generally poor. Full length compression (lower limbs and abdomen) and compression of solely the abdomen were found to be superior to knee-length and thigh-length compression. Both significantly reduced the fall in systolic blood pressure after postural change. Symptoms of orthostatic hypotension experienced by patients were improved the most by full-length compression. CONCLUSIONS: When other interventions fail to ameliorate symptoms, compression therapy can be considered. This review demonstrates that compression treatment should include the abdomen as this has the greatest beneficial effect. However, this review also displays the paucity of evidence for compression therapy for patients with orthostatic hypotension, and further investigation is certainly warranted.

Absence of an interaction between the synthetic pentasaccharide fondaparinux and oral warfarin.

AIMS: To investigate the pharmacokinetic and pharmacodynamic interaction of the antithrombotic pentasaccharide fondaparinux (Org31540/SR90107A), given subcutaneously, and oral warfarin in healthy subjects. METHODS: This study was performed according to a randomised, three-way cross-over, placebo-controlled, double-blind design in 12 healthy male subjects. The treatment consisted of five subcutaneous (s.c.) injections of fondaparinux (4 mg) or placebo at 24 h intervals. Oral dosing of warfarin or placebo was added to the fourth (15 mg) and fifth (10 mg) s.c. injection. Blood samples for pentasaccharide assay, PT and APTT were drawn before the first s.c. dose of the pentasaccharide and over a 6 day period thereafter. RESULTS: Fondaparinux administered to healthy male volunteers alone or in combination with oral warfarin was well tolerated and no serious adverse events were observed. No differences were found in the AUC (43 vs 44 mg l(-1) h), Cmax (645 vs 678 ng ml(-1)) or elimination half-life (13.8 vs 14.1 h) of fondaparinux between the pentasaccharide-only and the combination treatment. The effect of warfarin on PT (mean maximal increase: 8.2 s.) was not influenced by the presence of the pentasaccharide (mean maximal increase in PT: 9.1 s.). After all treatments a small rise in APTT was seen. No further differences could be detected in the pharmacodynamic parameters following the three treatments. CONCLUSIONS: The coadministration of warfarin did not influence the pharmacokinetics of fondaparinux in healthy subjects. PT can still be used to monitor the effect of oral anticoagulants during the switch from antithrombotic treatment with pentasaccharide to full oral anticoagulant therapy.

The oral bioavailability of pentosan polysulphate sodium in healthy volunteers.

OBJECTIVE: Pentosan polysulphate sodium (PPS), a heparin-like drug, is supposed to be orally applicable. The objective of the present study was to assess the oral bioavailability of PPS. However, since specific assays for PPS do not exist, this was done by using primary and secondary effect parameters. METHODS: The study was carried out using a three-way randomized crossover design with 18 healthy young male volunteers. The subjects received three treatments: PPS i.v. (50 mg), PPS orally (1500 mg) and placebo (orally). Blood sampling was done for activated partial thromboplastin time (APTT), anti-Xa activity, hepatic triglyceride lipase, lipoprotein lipase, tissue plasminogen activator (t-PA) activity, fibrin plate lysis, total triglyceride, total cholesterol, HDL and LDL. RESULTS: Intravenously administered PPS significantly increased APTT, anti-Xa activity, hepatic triglyceride lipase and lipoprotein lipase compared with placebo in a magnitude comparable to other i.v. heparin-like compounds. Orally administered PPS did not significantly influence any of the parameters when compared with placebo. Point estimates for the oral bioavailability of PPS were in the range of 0% with small confidence intervals (CIs). CONCLUSION: The oral bioavailability of PPS is negligible in young healthy males.

The effect of warfarin on the pharmacokinetics and pharmacodynamics of napsagatran in healthy male volunteers.

OBJECTIVE: The effect of oral warfarin on the pharmacokinetics and pharmacodynamics of the synthetic direct thrombin inhibitor napsagatran was investigated. METHODS: In an open, randomised, two-way crossover study, 12 healthy male volunteers were infused napsagatran (80 micrograms/min) for 48 h. Each subject was administered 25 mg warfarin (Coumadin) at the start of the infusion in either the first or second treatment period. Sampling was performed regularly over the treatment period and 24 h thereafter for measurement of plasma levels of napsagatran, activated partial thromboplastin time (APTT) and prothrombin time (PT). RESULTS: The pharmacokinetic parameters of napsagatran were not significantly influenced by co-administration of warfarin. Napsagatran administration was followed by increases in APTT and PT. Co-administration of warfarin increased the AUEC (area under the effect curve) calculated for the period 0-48 h (corrected for baseline) for APTT by 45% (95% CI: 28-65%) and for PT by 438% (95% CI: 272-678%) compared to the treatment with napsagatran alone. CONCLUSION: Warfarin has no effect on the pharmacokinetics of napsagatran, but has a marked influence on the pharmacodynamic parameters (APTT, PT) of napsagatran. In clinical practice, this interaction between the two compounds should be taken into account. The PT cannot be used to monitor the effect of oral anticoagulants during the switch from this group of direct thrombin inhibitors to full oral anticoagulant therapy.