Revised: 26 June 2013
Medsafe uses a variety of methods to collect information on the safety and quality of medicines and vaccines after they have been approved. These activities are known as pharmacovigilance.
Before a medicine is marketed any experience of its safety and efficacy is limited to its use in clinical trials. However clinical trials do not always reflect the actual use of a medicine or vaccine in real life. For example, a medicine may only have been tested in a relatively small number of people for a limited length of time.
Although Medsafe may receive extensive information from clinical trials for a specific medicine, some adverse reactions are rare and may not be seen until a very large number of people have taken the medicine. For this reason, it is very important to monitor all medicines after they have been approved.
Information from many sources is used for pharmacovigilance, including:
The main aim of pharmacovigilance is to identity signals of a possible problem.
Spontaneous suspected adverse reaction reports are case reports of suspected adverse reactions or adverse events that people have experienced while taking a medicine. The Ministry of Health (through Medsafe) contracts the collection of this information to the New Zealand Pharmacovigilance Centre at the University of Otago in Dunedin.
Healthcare professionals and consumers are encouraged to report any suspected adverse reaction to a medicine or vaccine to the Cetnre for Adverse Reactions Monitoring (CARM, part of the New Zealand Pharmacovigilance Centre).
Pharmaceutical companies also submit adverse reaction reports associated with the use of their products to CARM in Dunedin.
Adverse events are unwanted and sometime harmful outcomes which happen after taking a medicine. An adverse event does not mean that the medicine was the cause of the event. Adverse events include adverse reactions (side effect).
Adverse reactions are known undesirable effects to medicines or vaccines.
Whilst some reactions may occur when a medicine is used at higher than recommended doses, adverse reactions may also occur when normal doses are used.
Reactions may be evident within minutes or years after exposure to the medicine and may range from minor reactions like a skin rash to serious and life-threatening events such as a heart attack or liver damage.
More information on adverse reactions can be found in the Consumer Medicine Information (CMI), on the package labelling or by asking your healthcare professional.
These reports have been shown to be a very quick and effective way of finding potential or possible safety signals with medicines. They can be used to monitor the safety of medicines in real life use over the lifetime of the medicine and for all types of people.
The limitations of using spontaneous reports include under-reporting (i.e. some cases may not be reported), a lack of reliable information on the number of people taking the medicine, and incomplete information on diagnosis and history of the patient. Spontaneous reports are also not very effective at detecting adverse reactions that occur a long time after starting the medicine. For this reason spontaneous reports are only used to detect safety signals and are not used to investigate or confirm them. Information obtained from spontaneous reports need to be interpreted with caution.
A safety signal is an indication that there may be a safety problem related to a medicine. This could be a previously unknown adverse reaction or a change in the frequency or severity of a known side effect.
Medsafe analyses adverse reactions reports in conjunction with other information to determine if the safety signal is real. Medsafe seeks the advice of independent experts, via the Medicines Adverse Reactions Committee or may also form working groups of experts to provide advice. Medsafe also works closely with other regulatory authorities from around the world.
Medsafe undertakes a risk-benefit assessment on safety signals to assess if action is required.
The majority of safety signals are not supported by any additional information and no action is taken although Medsafe may continue to closely monitor the issue.
A small number of possible safety signals are confirmed to be real. In these cases Medsafe takes appropriate action to ensure the safe use of these medicines is improved.
Communication with healthcare professionals and consumers is one of the best ways to provide information about about adverse effects and the safe use of medicines.
Medsafe provides information by:
Medsafe can also instruct other organisations to provide information to healthcare professionals or consumers (eg, "Dear Healthcare Professional" letters from pharmaceutical companies).
Neither Medsafe nor CARM can say in individual cases that a medicine was the actual cause of a suspected adverse reaction. Any consumer who has concerns regarding medicines they are taking should discuss these with their GP.