NPC Archive Item: November Drug Safety Update from MHRA/CHM

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12th November 2008

The MHRA and CHM have published the November edition of Drug Safety Update. This issue highlights the adverse psychiatric effects of varenicline▼, including depression, and compatibility problems with a new formulation of tigecycline▼. The Hot Topic considers the evidence for and against an increased risk of cancer with ezetimibe▼, and Stop Press articles outline the withdrawal of rimonabant▼; new data on the risk of death or stroke with inhaled anticholinergics; and the limited evidence that paracetamol use in infancy increases the risk of asthma.

Drug Safety Update (DSU) is an essential read for everyone whose professional practice involves medicines. It is published every month in electronic format only.

As reported in previous issues of DSU (Dec.07, Feb.08, Jul.08), depression and suicide-related events have been reported in patients who are trying to stop smoking using varenicline. Further advice for health professionals is provided in this month’s issue. Patients who are taking varenicline who develop suicidal thoughts or who develop agitation, depressed mood, or changes in behaviour that are of concern for the doctor, patient, family, or caregiver should stop their treatment and contact their doctor immediately (See also MeReC Stop Press blog).

The antibacterial, tigecycline has been re-formulated and there are important differences between the old and new formulations that affect safe use of the drug. A table in DSU shows the known compatibilities and incompatibilities of the new formulation.

As we have previously blogged (See MeReC Rapid Review Blog), the SEAS trial raised concerns about the safety of ezetimibe, because there was an increased incidence of cancer in the active treatment group. However, this increase was not seen in two large, ongoing trials of ezetimibe. DSU states that the data currently available are insufficient to draw any conclusions. Further assessments will be done when the results of the ongoing trials are available.

DSU offers a reminder that the MHRA announced the Europe-wide suspension of the Marketing Authorisation for rimonabant following recommendations from the EMEA’s Committee for Medicinal Products for Human Use. As we reported in a previous MeReC Stop Press blog, the EMEA review concluded that the benefits of rimonabant do not outweigh the risks of psychiatric reactions in clinical use.

Inhaled anticholinergics in COPD
As we have previously reported (see MeReC Rapid Review blog No. 205 and No. 223), there is some evidence to suggest that inhaled anticholinergic drugs (ipratropium, tiotropium) increase the risk of cardiovascular (CV) events in people with chronic obstructive pulmonary disease (COPD) compared with placebo or active comparators (inhaled corticosteroids and/or beta-agonists). However, no such increased risk was demonstrated in the UPLIFT study. Because of the uncertainty, it is difficult to draw firm conclusions on the risk associated with inhaled anticholinergics. DSU concludes that further analyses are needed to shed light on any increased risk, and recommends that patients who take tiotropium for COPD should not exceed the recommended dose.

Paracetamol use in infancy
The CHM has reviewed the results of a recent study, which suggested that paracetamol use in the first year of life, or during the previous 12 months, or both, was associated with an increased risk of asthma in children aged 6–7 years old. They concluded that the study does not provide strong evidence of an association, and DSU advises that the study results do not necessitate any change to current guidance for paracetamol use in children. A MeReC Rapid Review Blog has discussed the limitations of the study.

Other information

  • Patient Information Leaflet of the month: Telfast®
  • ‘My medicine’: new section on MHRA website
  • Device bulletin: use of in vitro diagnostic devices with other medical equipment
  • Herbal medicines: packaging shows MHRA approval

Yellow Card scheme update
Reporting by community pharmacists is encouraged for over-the-counter medicines.

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