Centrally acting antihypertensives and alpha-blockers in people at risk of falls: therapeutic dilemmas-a clinical review

PURPOSE

The aim of this clinical review was to summarise the existing knowledge on the adverse effects of alpha-blockers and centrally acting antihypertensives, the effect these may have on falls risk, and guide deprescribing of these medications.

METHODS

Literature searches were conducted using PubMed and Embase. Additional articles were identified by searching reference lists and reference to personal libraries. We discuss the place of alpha-blockers and centrally acting antihypertensives in the treatment of hypertension and methods for deprescribing.

RESULTS

Alpha-blockers and centrally acting antihypertensives are no longer recommended for the treatment of hypertension unless all other agents are contraindicated or not tolerated. These medications carry a significant falls risk and non-falls risk-associated side effects. Tools to aid and guide de-prescribing and monitoring of the withdrawal of these medication classes are available to assist the clinician including information on reducing the risk of withdrawal syndromes.

CONCLUSIONS

Centrally acting antihypertensives and alpha-blockers increase the risk of falls through a variety of mechanisms-principally by increasing the risk of hypotension, orthostatic hypotension, arrhythmias and sedation. These agents should be prioritised for de-prescribing in older frailer individuals. We identify a number of tools and a withdrawal protocol to aid the clinician in identifying and de-prescribing these medications.

Safety of direct oral anticoagulants (DOACs) vs. warfarin for people aged ≥ 75 years with atrial fibrillation: a cohort study

Introduction

Warfarin significantly reduces the risk of stroke in people with atrial fibrillation (AF), but historically has been underused in older people due to complicated dosage regimens. DOACs offer an attractive alternative to warfarin and were shown to be non-inferior in randomised controlled trials, however older people were underrepresented in these trials and there have been few studies investigating outcomes specifically in this high risk group (1).

Aim

To compare the risk of major, non-major, gastrointestinal, and intracranial bleeding between warfarin and DOACs in people aged ≥ 75 years with AF.

Methods

A cohort of patients aged ≥ 75 years with a diagnosis of AF was extracted from the Clinical Practice Research Datalink (CPRD). Patients could enter the study on the date of their first prescription for warfarin or a DOAC between 1/1/2013 and 27/12/2017. Patients were censored on the date of the outcome, death, or leaving the general practice. Switching between anticoagulants and unexposed periods were measured using prescription mapping. Crude and adjusted hazard rates of the risk of bleeding were calculated using a Cox proportional hazards model with oral anticoagulant prescribing as a time varying covariate.

Results

The cohort included 10,149 patients in the warfarin group and 10,237 in the DOAC group. The groups had similar characteristics and the average age was 81 in the warfarin group and 82 in the DOAC group. The table summarises the results. Whilst major and non-major bleeding was similar between all DOACs and warfarin, rivaroxaban was associated with higher risk and apixaban lower risk when analysed separately. Risk of gastrointestinal bleeding was higher with all DOACs and rivaroxaban than warfarin but apixaban was not significantly different. Few intracranial events occurred (n=131).

Conclusion

The results indicate that DOACs as a group are not significantly different to warfarin, however when analysed separately, apixaban may be safer. While the study relies on prescription data and hence it is not known if patients were taking the medications, the large cohort studied is representative of older people who are prescribed these medications in UK primary care.

Reference

(1) Mitchell A, Watson MC, Welsh T, McGrogan A. Effectiveness and safety of direct oral anticoagulants versus vitamin K antagonists for people aged 75 years and over with atrial fibrillation: A systematic review and meta-analyses of observational studies. Journal of Clinical Medicine. 2019; 8 (554).

Fracture risk is under-recognised and under-treated in memory clinic attendees

UK national guidelines recommend that older people at risk of falling should have their fracture risk assessed and acted upon. People with cognitive impairment are more likely to sustain a fracture than their cognitively intact peers. We assessed the fracture risk of 79 memory clinic attendees and compared their actual management with guidelines. Despite reporting 57 falls in the last year, only 36% of those who would be recommended antiresportive treatment were prescribed it and a dual-energy X-ray absorptiometry (DEXA)scan was performed in only 13% where it would be recommended. These findings highlight an important deficit in fracture risk assessment which should inform future interventions.

Irradiation biology of male brown marmorated stink bugs: is there scope for the sterile insect technique?

PURPOSE

Brown marmorated stink bugs, Halyomorpha halys Stål (Hemiptera: Pentatomidae), are regularly intercepted, but there are few eradication tools. Currently, no sterile insect technique program exists for Hemiptera.

MATERIALS AND METHODS

Adult males were irradiated at 4-60 Gy, mated and their progeny reared for two generations, with mortality assessed at F₁ egg, F₁ adult and F₂ egg stages.

RESULTS

The F₁ eggs showed a dose response to irradiation between 4 and 36 Gy, with 97% sterility at 16 Gy, and higher doses producing complete egg mortality. Only rare F₁ survivors had progeny, but the F₂ generation showed identical responses between maternal and paternal lines; most egg batches showed either very low or very high mortality. Irradiation with 16 Gy resulted in 98.5% sterility, cumulative over F₁ and F₂.

CONCLUSIONS

Lack of a dose response at the F₂ generation precludes the use of irradiation-induced inherited sterility. The conventional sterile insect technique appears possible by irradiation of males from ∼12 to 16 Gy. The effect of radiation dose on females is not known, thus we cannot conclude whether bi-sex release is feasible so for now the release of males only is recommended. More work is needed on the competitive fitness of irradiated males, and logistics such as mass rearing or field collection, in order to determine the feasibility of the approach.

Kidney and spleen twin grafts in rats: unidirectional graft acceptance in unsuppressed ACI recipients

In previous studies, we have shown that vascularized spleen grafts can facilitate the acceptance of simultaneously implanted hearts, especially if host splenectomy is done 3 days later. The present study shows that the same protocol works not only for hearts but also for kidneys. A total of 59 renal allografts were carried out in various combinations between LEW and ACI rats. The recipients were submitted to bilateral nephrectomy at the time of graft implantation and host splenectomy 3 days later. Graft function was assessed by survival time of the animals. In addition, BUN, creatinine, and hematocrit were measured in selected individuals. The following observations were made: 1) LEW kidneys were rejected at 92 +/- 65 days while ACI kidneys failed at 17 +/- 1.4 days (p less than 0.025). 2) Control animals without simultaneous syngenic functioning spleen implant rejected their LEW kidneys at 30.6 +/- 24.3 days (p less than 0.005). 3) Eleven rats never rejected their LEW kidneys (four single, seven twin grafts). 4) BUN, creatinine, and hematocrit differed significantly in rats with functioning kidneys compared to those in end stage renal failure (p less than 0.0005, p less than 0.0025, and p less than 10(-7) respectively). It is concluded that the presence of the donor spleen can facilitate the acceptance of a simultaneous kidney graft to various degrees, depending on the strain combination.

Malignant nephroblastoma in Macaca fascicularis

A case of malignant nephroblastoma was identified in a 4.5-month-old female Macaca fascicularis. The age of onset, clinical history, gross and microscopic pathology, and the pulmonary metastasis were analogous to this condition as seen in man.

Acute gastric dilatation in monkeys: a microbiologic study of gastric contents, blood and feed

Twenty-one of 24 simian primates with acute gastric dilatation had Clostridium perfringens in their gastric contents. Only 2 of 18 normal animals contained this organism in their gastric contents. Clostridium perfringens was isolated from monkey biscuits taken from the cages of five affected animals and from five of 11 incoming lots of feed. After these biscuits were fed to normal animals, this organism could be isolated from the gastric contents. There were no other organisms isolated which could account for the voluminous gas production in this condition.

Development of a reversible vas deferens occlusion device. VII. Physical and microscopic observations after long-term implantation of flexible prosthetic devices

Flexible prosthetic devices developed previously to reversibly block sperm transport through the vas degerens were implanted in the vasa deferentia of dogs or kept in a semen bath for a 6-month period. Dimensional measurements, flow characteristics, leakage tests, and detent action force tests to displace the valve stem were performed with the valves. No changes occurred in any of these parameters with the exception of a decrease in the force required to change the position of the valve stem. This explains the occasional passage of spermatozoa through certain closed devices after they have been implanted for long periods of time. Histologic studies indicated that the same types of genital tract changes are associated with an implanted device as with vasectomy, and that they occur with approximately equal frequencies. Scanning electron microscope studies showed (1) excellent tissue ingrowth into the Dacron velour material of the implanted device; (2) the build-up of material, consisting in part of spermatozoa, in the device lumen and on the value stem; and (3) the absence of surface degradation of either the Silastic material or the valve stem of the device. It is concluded that no irreversible tissue damage is caused by the long-term implantation of flexible prosthetic devices into the vas deferens.