Prescribing Advice for GPs

Episodic hypertension and stroke risk

March 12, 2010 at 1:20 pm | In Prescribing Extra - Other |  Print | No Comments

The Lancet has published the results of an analysis that has identified a correlation between stroke risk and variability or maximal in systolic blood pressure (SBP). This study has been reported in the general media (BBC).

The study noted that guidelines for the treatment and diagnosis of hypertension focus upon assessment of blood pressure over a time period, essentially providing an average over the time the readings are taken. This study aimed to assess stroke risk in comparison to visit-to-visit variability in SBP (expressed in standard deviations) or maximum SBP using data from the UK-TIA and ASCOT-BPLA studies.

The analysis founds that mean SBP, variability in SBP (as standard deviation, coefficient of variation and variation independent of the mean) all positively correlated with stroke risk. The correlations in variability remained after correction for mean SBP.

Additionally, it was noted that the association was strong individuals in the top decile of variability and this association grew stronger after correction for mean SBP, age, sex and other risk factors (Hazard Ratio [HR] 12.08, 95% CI 7.40-19.72, p<0.0001). Maximum SBP was also strongly correlated after correction for mean SBP (HR 15.01, 95% CI 6.56-34.38, p<0.0001).

The authors note that their findings do not prove causality and recommend that consideration be given to how visit-to-visit strong>variability in blood pressure might be integrated into clinical practice. Attention is also drawn to the “false reassurance of a few normal blood-pressure readings “.

Action: Clinicians should be aware of this study. While clinical guidelines are reviewed perhaps it would be prudent to give a little more weight to one-off high blood pressure readings.

No Smoking Day – 2010

March 10, 2010 at 9:00 am | In Prescribing Extra - Other |  Print | No Comments

Today is No Smoking Day and this year the theme is WeQuit.

The web site contains information and resources to help people quit smoking. This year there is also an increase in use of internet and technology solutions such as a video blog, Twitter and Facebook pages and even an App for the iPhone that counts days, hours minutes and seconds since someone quit smoking and also how much money they have saved.

Action: Clinicians should be aware of these materials and use them to support local smoking cessation activities.

Drug Safety Update – March 2010

March 9, 2010 at 11:14 am | In Prescribing Extra - Drugs |  Print | No Comments

The Medicines and Healthcare products Regulatory Agency (MHRA) has published Drug Safety Update for March 2010 (PDF).

This issue contains drug safety advice regarding a possible small increase in the risk of congenital cardiac defects when fluoxetine is taken early in pregnancy. This information comes from an analysis of epidemiological data from seven cohort studies. The background rate of congenital cardiac defects is approximately 1/100 and these results indicate that fluoxetine increased absolute risk to less than 2/100 pregnancies. This is similar to the risk increase seen with paroxetine. Clinicians are advised that this potential for increased risk should be considered in the context of the benefits of treating depression in pregnancy.

Attention is also drawn to inter-test differences when monitoring therapeutic levels of sirolimus. These differences may inadvertently lead to inappropriate dose adjustments. Care should be taken to ensure that the test used is unchanged before making dose adjustments.

Finally, Drug Safety Update has been accredited by NHS Evidence in recognition of the high quality guidance that is issued. Future Drug Safety Updates will be available at http://www.evidence.nhs.uk and will display the accreditation mark.

Action: Clinicians will find this publication to be a useful review of current issues in drug safety.

SMC Update – March 2010

March 8, 2010 at 4:28 pm | In Prescribing Extra - Other |  Print | No Comments

The Scottish Medicines Consortium (SMC) has issued its monthly advice on new medicines.

Ketoprofen and omeprazole (Axorid^®) has been rejected for the symptomatic treatment of rheumatoid arthritis, ankylosing spondylitis and osteoarthritis in patients with a previous history or who are at risk of developing NSAID associated ulcers or erosions in whom continued treatment with ketoprofen is essential. The economic analysis provided was not sufficiently robust to gain approval.

Saxagliptin (Onglyza^®) has been accepted for restricted use in adult patients with type 2 diabetes mellitus as add-on combination therapy with metformin, when metformin alone, with diet and exercise, does not provide adequate glycaemic control. This agent is only recommended when the addition of sulphonylureas is not appropriate and is an alternative to other agents such as thiazolidinediones (glitazones).

Action: Clinicians should be aware of the recommendations of the SMC. Routine use of rejected and restricted medicines should be avoided.

Aspirin ineffective in those with low ABI

March 4, 2010 at 3:38 pm | In Prescribing Extra - Drugs |  Print | No Comments

The Journal of the American Medical Association (JAMA) has published the results of a study that aimed to assess the efficacy of aspirin in preventing primary cardiovascular events in patients with a low ankle brachial index (ABI).

ABI is the ratio of systolic blood pressure at the ankle and arm. ABI is used to diagnose peripheral vascular disease and is associated with an elevated risk of coronary events.

3,350 men and women aged 50 to 75 were recruited to the study. None had clinical cardiovascular disease but all had ABI less than or equal to 0.95. Follow up was for a mean of 8.2 years for a primary composite outcome of fatal or nonfatal coronary event, stroke or revascularisation. Participants were randomly assigned to treatment with 100mg aspirin daily or matching placebo.

The study found no significant difference in the rate of the primary outcome between the two study groups (Hazard Ratio 1.03, 95% confidence interval 0.84 – 1.27). Additionally, there were no differences in the two secondary outcomes (a composite of the primary outcome and angina, intermittent claudication or transient ischaemic attack or all-cause mortality). The study also assessed the rate of major haemorrhage requiring a hospital admission. This was higher in the patients treated with aspirin but the difference was not significant (HR 1.71, 95% CI 0.99 – 2.97).

The authors conclude that among this population “the administration of aspirin compared to placebo did not result in a significant reduction in vascular events“. The authors also suggest that ABI assessment is unlikely to be a useful screening tool in primary care settings.

The results of the study may be limited by low levels of medication compliance with the treatments taken for 60% of the trial person-years. Also, the study was designed and powered to detect a 25% relative reduction in events. Recent analyses have indicated that aspirin may only produce a 12% reduction and perhaps this study was underpowered.

Action: This study adds some more weight to the conclusions reached by the Drug and Therapeutics Bulletin that the use of aspirin in the primary prevention of cardiovascular events is unjustified.