Is nose‐to‐brain transport of drugs in man a reality?

The blood-brain barrier that segregates the brain interstitial fluid from the circulating blood provides an efficient barrier for the diffusion of most, especially polar, drugs from the blood to receptors in the central nervous system (CNS). Hence limitations are evident in the treatment of CNS diseases, such as Parkinson's and Alzheimer's diseases, especially exploiting neuropeptides and similar polar and large molecular weight drugs. In recent years interest has been expressed in the use of the nasal route for delivery of drugs to the brain, exploiting the olfactory pathway. A wealth of studies has reported proof of nose-to-brain delivery of a range of different drugs in animal models, such as the rat. Studies in man have mostly compared the pharmacological effects (e.g. brain functions) of nasally applied drugs with parenterally applied drugs and have shown a distinct indication of direct nose-to-brain transport. Recent studies in volunteers involving cerebrospinal fluid sampling, blood sampling and pharmacokinetic analysis after nasal, and in some instances parenteral administration of different drugs, have in my opinion confirmed the likely existence of a direct pathway from nose to brain.     

Is it time to regulate over‐the‐counter weight‐loss formulations?

Many products claiming to promote weight loss are freely available to purchase over the counter and are used by a substantial proportion of the population in many countries, who are often seeking rapid weight loss without long-term lifestyle changes. While there are multiple outlets for these products, surveys in England and Australia have found that at least 70% of community pharmacies stock these products and they are also available through internet pharmacies. Since the products are formulated as tablets and capsules, consumers may regard them as medicines, particularly when sold from a pharmacy. Manufacturers often make extravagant claims for their products, suggesting they suppress appetite, increase metabolism, block absorption of fat or carbohydrates and/or bring about diuresis, but there is little robust evidence of efficacy. Most products contain a variety of herbal ingredients and are not without adverse effects. Since very few of the hundreds of products sold in pharmacies are licensed medicines, they are not subject to the controls required for over-the-counter medicines, in terms of efficacy, safety, quality or provision of a standardised patient information leaflet. Pharmacists themselves perceive these products to be unsafe, but have little knowledge about them, other than that supplied by manufacturers. The role of community pharmacy in supporting effective weight management is increasingly important, given the rise in obesity. We question the widespread supply through pharmacies of ineffective products with extravagant claims and suggest that tighter regulation of their promotion and supply may be required.     

Similar renoprotection after renin‐angiotensin‐dependent and ‐independent antihypertensive therapy in 5/6‐nephrectomized Ren‐2 transgenic rats: are there blood pressure‐independent effects?

1. Hypertension plays a critical role in the progression of chronic kidney disease (CKD) to end-stage renal disease (ESRD), but it has also been postulated that antihypertensive drugs that block the renin-angiotensin system (RAS) show class-specific renoprotective actions beyond their blood pressure (BP)-lowering effects. 2. Because this notion has recently been questioned, in the present study we compared the effects of a RAS-dependent antihypertensive therapy (a combination of trandolapril, an angiotensin-converting enzyme inhibitor (ACEI) and losartan, an angiotensin-II (AngII) receptor subtype 1A receptor antagonist) with a 'RAS-independent' antihypertensive therapy (a combination of labetalol, an alfa- and beta-adrenoreceptor antagonist with the diuretics, hydrochlorothiazide and furosemide) on the progression of CKD after 5/6 renal ablation (5/6 NX) in Ren-2 renin transgenic rats (TGR), a model of AngII-dependent hypertension. Normotensive transgene-negative Hannover Sprague-Dawley (HanSD) rats after 5/6 NX served as controls. 3. RAS-dependent and -independent antihypertensive therapies normalized BP and survival rate, and prevented the development of cardiac hypertrophy and glomerulosclerosis to the same degree in 5/6 NX HanSD rats and in 5/6 NX TGR. The present findings show that renoprotection, at least in rats after 5/6 NX, is predominantly BP-dependent. When equal lowering of BP was achieved, leading to normotension, cardio- and renoprotective effects were equivalent irrespective of the type of antihypertensive therapy. 4. These findings should be taken into consideration in attempts to develop new therapeutic approaches and strategies aimed to prevent the progression of CKD and to lower the incidence of ESRD.     

Is a one‐week course of triple anti‐Helicobacter pylori therapy sufficient to control active duodenal ulcer?

BACKGROUND: Triple therapy currently forms the cornerstone of the treatment of patients with Helicobacter pylori-positive duodenal ulcer. AIM: To establish whether prolonged antisecretory therapy is necessary in patients with active duodenal ulcer. METHODS: A total of 77 patients with H. pylori-positive duodenal ulcer were included in a prospective, controlled, double-blind study. All patients received a 7-day treatment with omeprazole 20 mg b.d., clarithromycin 500 mg b.d. and amoxicillin 1000 mg b.d. Patients in the omeprazole group underwent an additional 14-day therapy with omeprazole 20 mg; patients in placebo group received placebo. Endoscopy was performed upon inclusion in the study and after 3 and 8 weeks. RESULTS: Seventy-four patients were eligible for a per protocol analysis after 3 weeks, and 65 after 8 weeks. After 3 weeks, the healing rate was 89% in the omeprazole group and 81% in the placebo group (P=0.51). After 8 weeks, the ulcer healed in 97% of the patients in the total group (95% CI: 92.7-100%). H. pylori was eradicated in 88% of patients in the omeprazole group and in 91% in the placebo group (P=1.0). No statistically significant differences between the groups were found in ulcer-related symptoms or in ulcer healing. CONCLUSION: In patients with H. pylori-positive duodenal ulcer, a 7-day triple therapy alone is sufficient to control the disease.     

Is there a role for day‐to‐day home blood pressure variability in guiding management of hypertension?

相似文献   

Existence of a Clinically Relevant Interaction between Clopidogrel and HMG‐CoA Reductase Inhibitors? Re‐evaluating the Evidence

Clopidogrel is an inactive prodrug, which requires activation by the cytochrome P450 3A4 system in order to exert its antiplatelet action. Some statins (atorvastatin, lovastatin and simvastatin) also requires metabolism by the cytochrome P450 3A4 system. From a theoretical point of view, a clinical relevant interaction may exist between clopidogrel and cytochrome P450 3A4 metabolized statins. Nine studies have investigated the existence of this potential interaction. Seven studies have used results based on platelet function as surrogate endpoints and two studies have dealt with objective clinical events including mortality, acute myocardial infarction and stroke. However the studies have yielded conflicting results. This controversy is primarily caused by substantial differences in study design and methods used for assessment of the antiaggregatory effect of clopidogrel. Most studies have included too few patients, and there appears to be no consensus regarding the definition of and optimal way of measuring the platelet inhibitory effect of clopidogrel. Therefore an adequately powered prospective study, ensuring elimination of identified possible confounders and with the use of a well-defined surrogate ex vivo parameter should be performed.     

Is a long‐term ranitidine‐based triple therapy against Helicobacter pylori only a heritage of the past? A prospective,randomized clinicopharmacological study

BACKGROUND: Acid suppression plus two antibiotics is currently considered the gold standard anti-Helicobacter pylori treatment, but the effective role of gastric antisecretory drugs is still poorly understood. Aims: To compare a 14-day ranitidine-based triple regimen against Helicobacter pylori with one based on omeprazole, and to study the influence of antisecretory drugs on metronidazole pharmacokinetics in human plasma. METHODS: A total of 150 dyspeptic H. pylori-infected patients were randomized for ranitidine 300 mg b.d. (RCM group) or omeprazole 20 mg b.d. (OCM group) 14-day triple therapy, with clarithromycin 500 mg b.d. and metronidazole 500 mg b.d. On the eighth day of therapy, metronidazole pharmacokinetics was studied in plasma by high-performance liquid chromatography. The pharmacokinetic parameters (terminal half-life, area under the curve, peak-plasma level, peak time) of metronidazole were computed using standard non-compartmental methods. H. pylori status was monitored before and 4 weeks after the end of therapy by histology, serology and rapid urease test. RESULTS: On an intention-to-treat basis, eradication rates were 91 and 76% for the RCM and OCM groups respectively (P < 0.02). Significantly different pharmacokinetic parameters of metronidazole were found between the groups: peak-plasma level (P < 0.01) and area under the curve (P < 0.02). CONCLUSION: Our results show that the RCM regimen was more effective than that based on OCM and that the antisecretory drugs affected metronidazole availability, increasing the efficacy of ranitidine-based regimens.     

A double‐blind placebo‐controlled study of buspirone‐stimulated prolactin release in non‐ulcer dyspepsia—are central serotoninergic responses enhanced?

BACKGROUND: Dyspepsia is a common symptom for which an organic cause is found in only 40% of patients. When no cause is apparent and the dyspepsia is considered to be idiopathic, a diagnosis of non-ulcer dyspepsia is made. The pathophysiology of non-ulcer dyspepsia is poorly understood and numerous theories have been put forward, including a theory of enhanced central serotoninergic receptor sensitivity. AIM: To determine the sensitivity of serotonin receptors in non-ulcer dyspepsia. METHODS: Using a randomized, double-blind, placebo-controlled design, we compared buspirone (a serotonin type 1a partial agonist)-stimulated prolactin release in 50 patients and 59 healthy comparison subjects. Buspirone, 30 mg, or matching placebo was administered on two separate occasions and prolactin release over 180 min was monitored. Patients and healthy subjects received both treatments in random order, 1 week apart. RESULTS: Overall, patients with non-ulcer dyspepsia had greater prolactin release in response to the buspirone challenge than the healthy comparison subjects, with differences most significant at 90 min following the challenge. Enhancement occurred in patients both with and without Helicobacter pylori infection. Female subjects, both patients and healthy volunteers, showed a greater response to buspirone than male subjects, and the augmentation of response observed in male and female patients was greater in females. CONCLUSIONS: Patients with non-ulcer dyspepsia have enhanced central serotoninergic responses and such responses are independent of H. pylori infection. Blockade of such receptors might be an appropriate therapeutic strategy.     

Is a 9‐month treatment sufficient in tuberculous enterocolitis? A prospective,randomized, single‐centre study

BACKGROUND: Tuberculosis has increased in parallel with the acquired immunodeficiency syndrome epidemic and the use of immunosuppressive therapy, and the growing incidence of extra-pulmonary tuberculosis, especially with intestinal involvement, reflects this trend. However, the duration of anti-tuberculous therapy has not been clarified in intestinal tuberculosis. AIM: To compare the efficacy of different treatment durations in tuberculous enterocolitis in terms of response and recurrence rates. METHODS: Forty patients with tuberculous enterocolitis were randomized prospectively: 22 patients into a 9-month and 18 into a 15-month group. Diagnosis was made either by colonoscopic findings of discrete ulcers and histopathological findings of caseating granuloma and/or acid-fast bacilli, or by clinical improvement after therapeutic trial. Patients were followed up with colonoscopy every other month until complete response or treatment completion, and then every 6 months for 1 year and annually. Complete response was defined as a resolution of symptoms and active tuberculosis by colonoscopy. RESULTS: Complete response was obtained in all patients in both groups. Two patients in the 9-month group and one in the 15-month group underwent operation due to intestinal obstruction and perianal fistula, respectively. No recurrence of active intestinal tuberculosis occurred during the follow-up period in either group. CONCLUSIONS: Tuberculous enterocolitis can be managed by 9-month chemotherapy without disease recurrence. Further investigations are needed in immunocompromised patients.     

Do we need a new gastro‐oesophageal reflux disease questionnaire?

BACKGROUND: Gastro-oesophageal reflux disease (GERD) is highly prevalent in Western countries. Because the majority of patients do not present with endoscopic abnormalities, the assessment of the symptom severity and quality of life, and their response to treatment, has become increasingly important. Self-assessed symptom questionnaires are now key instruments in clinical trials. AIM: To evaluate the validity of available GERD measurement tools. METHODS: An ideal GERD symptom assessment instrument, suitable as a primary end-point for clinical trials, should possess the following characteristics: (i) be sensitive in patients with GERD; (ii) cover the frequency and intensity of typical and atypical GERD symptoms; (iii) be multidimensional (cover all symptom dimensions); (iv) have proven psychometric properties (validity, reliability and responsiveness); (v) be practical and economical; (vi) be self-assessed; (vii) use 'word pictures' which are easy to understand for patients; (viii) respond rapidly to changes (responsiveness over short time intervals); (ix) be used daily to assess changes during and after therapy; and (x) be valid in different languages for international use. RESULTS: A literature review revealed five scales that met some of the above characteristics, but did not fulfil all criteria. CONCLUSION: There is a need for a new evaluative tool for the assessment of GERD symptoms and their response to therapy.     

Approaches to endoscopic‐negative reflux disease: part of the GERD spectrum or a unique acid‐related disorder?

Endoscopic-negative reflux disease (ENRD) is the most common presentation of gastro-oesophageal reflux disease (GERD)-affecting up to 70% of these individuals. In the last three decades therapeutic studies have focused solely on the treatment of patients with erosive oesophagitis. However, more recent studies have shifted our attention to defining, understanding and treating those with ENRD. GERD has traditionally been approached as a spectrum with ENRD at the mild end and complicated GERD (i.e. patients with erosive oesophagitis, stricture and Barrett's oesophagus) being at the other end, suggesting that patients' disease may progress over time along the spectrum. Current data indicate that ENRD should be approached as a unique entity rather than a part of the GERD spectrum and that over time only a few patients with ENRD will develop GERD-related complications. Patients with ENRD are a heterogenous group of patients with different aetiologies for their heartburn symptoms, including motor events, reflux of acidic or nonacidic gastric contents, minute changes in intraesophageal pH (pH < 4), mucosal hypersensitivity, and emotional or psychological abnormalities. By dropping the spectrum concept, which emphasizes oesophageal mucosal injury, we can focus our attention on the specific mechanisms that lead to symptom generation in each of the three unique groups of GERD (ENRD, erosive oesophagitis and Barrett's oesophagus) and on the specific therapeutic modalities that benefit each of these individual groups. Acid suppressive therapy with proton pump inhibitors is highly effective in healing erosions and controlling symptoms in those with erosive oesophagitis. In those with ENRD the resolution or control of heartburn with proton pump inhibitor therapy is greater than that with placebo or H2 receptor antagonist, but not as consistent nor as impressive as the results observed in studies of patients with erosive oesophagitis. By considering the mechanisms involved in ENRD symptom generation, future studies that include high-dose proton pump inhibitors, promotility agents (alone or in combination with proton pump inhibitors), transient lower oesophageal sphincter reducers, or pain modulators (e.g. tricyclic antidepressant agents) may prove beneficial.