Aspirin: a novel antihypertensive drug? Or two birds with one stone?

Comparative Analysis of Compatibility Influence on Invigorating Blood Circulation for Combined Use of Panax Notoginseng Saponins and Aspirin Using Metabolomics Approach

The combined use of Panax notoginseng saponins (PNS)–based drugs and aspirin (ASA) to combat vascular diseases has achieved good clinical results. In this study, the superior efficacy was observed via the combined use of PNS and ASA on acute blood stasis rats, and untargeted metabolomics was performed to holistically investigate the therapeutic effects of coupling application and its regulatory mechanisms. The combined use of PNS and ASA exhibited better improvement effects when reducing the evaluated hemorheological indicators (whole blood viscosity, plasma viscosity, platelet aggregation, and fibrinogen content) in the blood stasis rats vs. single use of PNS or ASA at the same dose. The combined use of both drugs was the most effective application method, as shown by the relative distance in partial least-squares discriminant analysis score plots. Twelve metabolites associated with blood stasis were screened as potential biomarkers and were mainly involved in amino acid metabolism, lipid metabolism, and energy metabolism. After coherently treated with PNS and ASA, the altered metabolites could be partially adjusted to be closer to normal levels than single use. The collective results revealed that PNS could cooperate with ASA to treat blood stasis and provided a scientific explanation for the superior efficacy of their combined use.

Evaluation of the antihypertensive effect of nocturnal administration of acetylsalicylic acid: a cross-over randomized clinical trial

OBJECTIVE

Several studies have shown that evening intake of aspirin has antihypertensive effect in healthy adults, which has not been proven in patients with cardiovascular disease, who mostly take aspirin in the morning. We have evaluated the antihypertensive effect of bedtime administration of aspirin in patients with cardiovascular disease already treated for hypertension.

METHODS

This is a multicenter randomized triple-blind placebo-controlled crossover trial, with hypertensive patients treated with aspirin for secondary prevention. There was a baseline-randomized assignment to 2-month periods of bedtime aspirin (100 mg) first and morning-time aspirin later, or inversely, both periods separated by an open label 2-4 weeks period of morning-time aspirin. At the start and end of each treatment period, a 24-h ambulatory blood pressure monitoring was performed. The main outcome measure was mean 24-h blood pressure. The analyses were performed according to the intention-to-treat principle.

RESULTS

Overall, 225 patients were randomized. No significant differences were observed in ambulatory blood pressure by time of intake of usual low doses of aspirin. The mean SBP/DBP was 123.2/69.9 (95% CI 121.58-124.9/68.86-76.86) with bedtime administration and 122.4/68.8 (95% CI 120.76-124.01/67.85-69.83) with daytime administration (P = 0.3 and P = 0.23 for SBP and DBP, respectively).

CONCLUSION

Administering aspirin at bedtime rather than in the morning does not modify the 24-h ambulatory blood pressure in hypertensive patients in secondary cardiovascular prevention.The trial was registered with ClinicalTrials.gov (number NCT01741922).

Aspirin use for primary prophylaxis: Adverse outcomes in non-variceal upper gastrointestinal bleeding

AIM: To compare outcomes of patients with non-variceal upper gastrointestinal bleeding (NVUGIB) taking aspirin for primary prophylaxis to those not taking it.

METHODS: Patients not known to have any vascular disease (coronary artery or cerebrovascular disease) who were admitted to the American University of Beirut Medical Center between 1993 and 2010 with NVUGIB were included. The frequencies of in-hospital mortality, re-bleeding, severe bleeding, need for surgery or embolization, and of a composite outcome defined as the occurrence of any of the 4 bleeding related adverse outcomes were compared between patients receiving aspirin and those on no antithrombotics. We also compared frequency of in hospital complications and length of hospital stay between the two groups.

RESULTS: Of 357 eligible patients, 94 were on aspirin and 263 patients were on no antithrombotics (control group). Patients in the aspirin group were older, the mean age was 58 years in controls and 67 years in the aspirin group (P < 0.001). Patients in the aspirin group had significantly more co-morbidities, including diabetes mellitus and hypertension [25 (27%) vs 31 (112%) and 44 (47%) vs 74 (28%) respectively, (P = 0.001)], as well as dyslipidemia [21 (22%) vs 16 (6%), P < 0.0001). Smoking was more frequent in the aspirin group [34 (41%) vs 60 (27%), P = 0.02)]. The frequencies of endoscopic therapy and surgery were similar in both groups. Patients who were on aspirin had lower in-hospital mortality rates (2.1% vs 13.7%, P = 0.002), shorter hospital stay (4.9 d vs 7 d, P = 0.01), and fewer composite outcomes (10.6% vs 24%, P = 0.01). The frequencies of in-hospital complications and re-bleeding were similar in the two groups.

CONCLUSION: Patients who present with NVUGIB while receiving aspirin for primary prophylaxis had fewer adverse outcomes. Thus aspirin may have a protective effect beyond its cardiovascular benefits.

Drug induced hypertension--An unappreciated cause of secondary hypertension

Most patients with hypertension have essential hypertension or well-known forms of secondary hypertension, such as renal disease, renal artery stenosis, or common endocrine diseases (hyperaldosteronism or pheochromocytoma). Physicians are less aware of drug induced hypertension. A variety of therapeutic agents or chemical substances may increase blood pressure. When a patient with well controlled hypertension is presented with acute blood pressure elevation, use of drug or chemical substance which increases blood pressure should be suspected. Drug-induced blood pressure increases are usually minor and short-lived, although rare hypertensive emergencies associated with use of certain drugs have been reported. Careful evaluation of prescription and non-prescription medications is crucial in the evaluation of the hypertensive individual and may obviate the need for expensive and unnecessary evaluations. Discontinuation of the offending agent will usually achieve adequate blood pressure control. When use of a chemical agent which increases blood pressure is mandatory, anti-hypertensive therapy may facilitate continued use of this agent. We summarize the therapeutic agents or chemical substances that elevate blood pressure and their mechanisms of action.

Drug-induced hypertension: an unappreciated cause of secondary hypertension

A myriad variety of therapeutic agents or chemical substances can induce either a transient or persistent increase in blood pressure, or interfere with the blood pressure-lowering effects of antihypertensive drugs. Some agents cause either sodium retention or extracellular volume expansion, or activate directly or indirectly the sympathetic nervous system. Other substances act directly on arteriolar smooth muscle or do not have a defined mechanism of action. Some medications that usually lower blood pressure may paradoxically increase blood pressure, or an increase in pressure may be encountered after their discontinuation. In general, drug-induced pressure increases are small and transient: however, severe hypertension involving encephalopathy, stroke, and irreversible renal failure have been reported. The deleterious effect of therapeutic agents is more pronounced in patients with preexisting hypertension, in those with renal failure, and in the elderly. Careful evaluation of a patient's drug regimen may identify chemically induced hypertension and obviate unnecessary evaluation and facilitate antihypertensive therapy. Once chemical-induced hypertension has been identified, discontinuation of the causative agent is recommended, although hypertension can often be managed by specific therapy and dose adjustment if continued use of the offending agent is mandatory. The present review summarizes the therapeutic agents or chemical substances that elevate blood pressure and their mechanisms of action.

Is there a BP benefit of changing the time of aspirin administration in treated hypertensive patients?

Background and design: The effects of aspirin on blood pressure (BP) are controversial and a chronopharmacological effect of aspirin on 24-hour BP was reported recently in otherwise untreated hypertensive patients. The study was designed to test the timing effect of aspirin dosing on 24-hour BP in treated hypertensive patients routinely taking aspirin for cardiovascular prevention.

Method and results: Seventy-five patients were randomized into two groups. One group was to receive aspirin in the evening then in the morning for 1 month and the other group in the morning then in the evening, following a cross-over design. The principal assessment criterion was 24-hour systolic BP (SBP) measured by 24-hour ambulatory BP monitoring (ABPM). Patients were aged 65 ± 9 years and had been hypertensive for 12 ± 10 years. They were all taking a mean of 2.8 antihypertensive drugs and did not modify their treatment throughout the study. Of the included subjects, 70% were men and 33% were diabetics. Mean 24-hour SBP values were clinically equivalent and were not statistically different, depending on whether the aspirin was taking in the morning or evening (128.3 ± 1.4 vs. 128.3 ± 1.4 mmHg, respectively). Neither was there any significant difference in diurnal and nocturnal SBP or in 24-hour, diurnal, and nocturnal diastolic BP (DBP).

Conclusion: It does not appear useful to advise patients with long-standing hypertension to modify timing of aspirin intake in order to reduce BP values.