An expert New Zealand committee reviewing the safety of a group of arthritis drugs called COX-2 inhibitors has reinforced UK advice cautioning against their routine use where safe and effective alternatives are available.
The Medicines Adverse Reactions Committee is advising patients who are using Celebrex, Arcoxia, Mobic and Bextra they should talk with their health care provider about alternatives if they have concerns.
The Medicines Adverse Reactions Committee (MARC) has discussed a rapid literature review of the risk of use of COX 2 inhibitor medicine causing increased risk of cardiovascular events (heart attacks and/or stroke).
The MARC concluded that the increased risk of heart attack found for rofecoxib (Vioxx) may also occur to some degree for all of the other members of the COX 2 group of anti-inflammatory agents. The MARC conclusion is supported by the subsequent report from the United States National Institute of Health that it had stopped one of two long-term (3 yrs) studies of celecoxib (Celebrex) in the prevention of colon polyps due to an increased risk of cardiovascular events. The increase in cardiovascular risk was similar in size to the 1.96 times increased risk found after 18 months treatment in the Vioxx study of colon polyp prevention that lead to Vioxx being removed from the market in October of this year.
The Adenoma Prevention with Celebrex study (APC) that has been stopped found that patients taking celecoxib at doses of 200mg twice a day and 400mg twice a day have an increased risk of developing a cardiovascular event compared to patients on placebo of 2.5 and 3.4 times respectively. While the average duration of treatment in the APC study was 33 months when it was stopped, the available data does not indicate when the increased cardiovascular risk first becomes apparent. A parallel study of celecoxib using 400mg once per day as a preventative agent for colon polyps for a similar period of time has not shown increased risk.
In October 2004 the Ministry of Health (Medsafe) asked the manufacturers of COX 2 medicines to supply it with all the data they hold on the cardiovascular safety of these medicines. Like other medicines regulators around the world, Medsafe is in the process of reviewing the massive volumes of data supplied by the manufacturers to determine if use of a COX -2 medicine increases the risk of a patient developing a cardiovascular event. This analysis is unlikely to be completed before March 2005.
In the interim the MARC indicated it broadly supports the guidance issued by the United Kingdom "National Institute of Clinical Excellence" (NICE), which was distributed to all GPs by the New Zealand Best Practice Advocacy Centre in October of this year.
The MARC key messages are:
- COX 2 agents are not recommended for routine use in patients with rheumatoid arthritis (RA) or osteoarthritis (OA) except in circumstances where the patient is at "high risk " of developing a serious gastrointestinal adverse effect from other standard non-steroidal anti-inflammatory agents;
- COX 2 agents should not be routinely prescribed to patients at high risk of cardiovascular events (absolute risk of event >15-20% over 5 years) as there remains uncertainty about the safety of these agents when used in this group of patients;
- Prescribing COX-2 agents to patients already taking aspirin cannot be justified on current evidence.
- The increased benefit associated with use of COX 2 agents in patients at high risk of serious gastrointestinal adverse effects (estimated as between a 4 and 8 times reduction in serious events), may outweigh the increased risk of cardiovascular events in patients at high risk of myocardial infarction.
- A signal is emerging that use of some COX 2 agents as painkillers after major surgery may be associated with an increased risk of cardiovascular events. The MARC therefore advises that until the full evaluation of all the safety data is complete COX 2 agents should not be routinely used for post-operatively pain relief.
Patients already taking COX 2 agents should discuss the continuing use of these medications with their GP, or specialist, the next time their prescription is due. Prescribers should discuss with their patients the available alternatives to the COX 2 agents and review the risks and benefits of these alternatives compared with the emerging clinical concerns about the COX 2 agents, before deciding on the best course of treatment for that individual. If the patient and prescriber decide that continued use of a COX 2 agent is appropriate, use of the lowest effective dose is prudent practice.
If patients are taking COX 2 agents on a regular basis and are concerned about their use of these medicines, they should discuss the risk and benefits of continued treatment with their healthcare provider. A number of alternative anti-inflammatory agents for the treatment of osteoarthritis and rheumatoid arthritis are available in New Zealand. Unlike the COX 2 agents, many of these agents are funded by PHARMAC.
COX 2 agents available in NZ include:
||Dynastat inj (parecoxib)|
Standard anti-inflammatory agents:
Naprosyn SR 750