Prescribing Advice for GPs

Hypertension Meta-Analysis

May 16, 2008 on 11:29 am | In Prescribing Extra - Drugs |  Print | No Comments

The British Medical Journal has published the results of a meta-analysis of hypertension trials that aimed to quantify the relative risk reductions achieved with different regimens in younger and older adults.

The study reviewed 31 trials, including 190,606 participants. The primary outcome was major cardiovascular events compared in two age groups, those under 65 and those over 65 years old. The data were analysed in several different ways to compare active treatments with placebo or alternative active comparators.

The study found no difference in the primary outcome when comparing different drug regimens (P≥0.24 in all cases) and there was no clear difference in blood pressure lowering effects in the different age groups. An accompanying editorial discusses some of the limitations in the study including the arbitrary age cut-off and also attempts to integrate the results of this analysis into the existing evidence base and current guidelines.

The authors conclude that, “Reduction of blood pressure produces benefits in younger and older adults, with no strong evidence that protection against major vascular events afforded by different drug classes varies substantially with age“.

Action: Clinicians should continue to implement the existing national guidelines for hypertension irrespective of age. Effective control of hypertension is key in the management of overall cardiovascular risk.

Bisphosphonates linked to AF

May 2, 2008 on 1:01 pm | In Prescribing Extra - Drugs |  Print | No Comments

The Archives of Internal Medicines has published the results of a case-control study that aimed to assess any relationship between alendronate use and risk of incident atrial fibrillation (AF).

The recent HORIZON study found an unexpected increase in the risk of AF in patients assigned to the study drug. This study reviewed an American patient database system for female patients diagnosed with AF between October 2001 and December 2004. 719 patients were identified and matched with 966 controls.

More patients in the AF group had used alendronate (6.5% versus 4.1%). Comparing use of alendronate with no use of any bisphosphonate the risk of AF was statistically higher (Odds ratio 1.86; 95% CI 1.09-3.15).

The authors conclude that, “use of alendronate was associated with an increased risk of incident AF“. This observational study demonstrates that there is an association but not one of cause and effect. Other factors may explain the increase in AF that has been observed and therefore additional studies would be required to demonstrate causality.

Action: Clinicians should be aware of this potential link and be vigilant for AF in patients prescribed alendronate.

Additional glitazone fracture data

April 30, 2008 on 10:07 am | In Prescribing Extra - Drugs |  Print | No Comments

The Archives of Internal Medicine has published the results of an analysis that examined the association between the use of glitazones or other oral anti-diabetic drugs and the risk of fracture.

The analysis queried the UK General Practice Research Database for patients aged 30 to 89 years who had a fracture between January 1994 and December 2005. Control patients were matched for age, gender and general practice attended.

The study identified 1,020 case patients with a low trauma fracture and 3,728 controls. After correction for several factors including age, body mass index and co-morbidities users of glitazones were at statistically higher risk of fractures; odds ratio 2.43 (95% confidence interval [CI], 1.49-3.95). The risk also appeared to be dose related. There were no detectable differences associated with the other oral anti-diabetic drugs.

The authors conclude that, “this analysis provides further evidence of a possible association between long-term use of thiazolidinediones [glitazones] and fractures“.

Action: Clinicians should reserve glitazone use for patients who are contraindicated to or cannot tolerate metformin and/or a sulphonylurea.

Enoxaparin contamination

April 28, 2008 on 3:47 pm | In Prescribing Extra - Drugs |  Print | No Comments

The Medicines and Healthcare products Regulatory Agency (MHRA) have issued a press release (PDF) warning clinicians about potential contamination of enoxaparin (Clexane^®) injections.

Enoxaparin is a low molecular weight heparin injection. Some batches contain low levels of an impurity called over-sulphated chondroitin sulphate (OSCS). New product entering the supply chain is unaffected.

Existing stocks are not being recalled because there is currently no evidence of risk to patients. Clinicians are advised to be extra vigilant to possible adverse drug reactions (ADRs). Patients are advised to seek advice from a healthcare professional if they have concerns.

Action: Clinicians should be aware of this issue. Patients may seek reassurance about continued treatment. Any suspected ADRs must be reported through the yellow card scheme.

Drug Evaluations for the gliptins

April 24, 2008 on 2:53 pm | In Prescribing Extra - Drugs |  Print | 1 Comment

The Regional Drug and Therapeutics Centre has produced New Drug Evaluations for sitagliptin (Januvia^®) and vildagliptin (Galvus^®).

The evaluation of sitagliptin recommends that this drug “may be considered as an option for patients who fail to achieve glycaemic control despite an adequate trial of established first and second-line regimens“. It also notes that long term safety and efficacy data are lacking.

The evaluation for vildagliptin makes the same recommendations and qualifies that an “appropriate place in treatment protocols is presently undetermined“.

The gliptins are a new drug class with data to support statistically significant improvements in HbA_1c. However, long term efficacy and safety are unknown and there are no data to demonstrate improvements in morbidity and mortality.

Action: The limitations above currently place these drugs as a last line option before moving to insulin in patients who have poor glycaemic control on established treatments or who are intolerant to established agents.