Where necessary, the benefit-risk balance may be improved either by increasing the benefits, for example including further explanation of how best to use the product, or by reducing the risks by risk mitigation measures, for example by contraindicating the use in animals particularly at risk, reducing dosage, or introducing precautions for use. The MAH should aim to optimise the safe use and the benefit-risk balance of an individual veterinary medicine. The reasoning leading to the conclusion should be explained and discussed in a critical manner. The assessment should describe and objectively compare the benefits and risks of the veterinary medicine to evaluate the benefit-risk balance. The benefit-risk assessment of a veterinary medicine is a complex process based on the intended use and the indications of that product in respect to its overall safety. A comprehensive report evaluating the issue and considering the risks in the context of the benefits should be submitted at the earliest opportunity, and no later than the date agreed between the MAH and the VMD, and should also be included in the relevant PSUR. The MAH is obliged to immediately inform the VMD of any prohibition or restriction imposed by the National Competent Authority (NCA) of any country in which the veterinary medicine is marketed and of any other new information which might influence the evaluation of the benefits and risks of the product concerned. It is the responsibility of the QPPV to provide the VMD with any information relevant to the evaluation of benefits and risks afforded by a veterinary medicine, including appropriate information on post-authorisation safety studies, lack of expected efficacy, information regarding the validity of the withdrawal period or potential environmental problems arising from the use of the veterinary medicine. The responsibilities of the MAH, and in particular of the QPPV, are provided in Pharmacovigilance Systems, including Risk Management and Compliance and Inspections. Rarely, even a single report of an unexpected adverse reaction may contain sufficient information to represent a signal on or establish a potential causal association with the suspected veterinary medicine and impact on the benefit-risk balance. Signals of possible unexpected adverse reactions or changes in severity, characteristics or frequency of expected adverse reactions may arise from any source. keeping health-care professionals and animal owners informed on changes to authorised veterinary medicine information.ensuring that appropriate action is taken in response to new evidence which impacts on the benefit-risk balance.ensuring that all sources of information are screened regularly to identify potential signals.In the example the first chart has more than twice the number of drops per millilitre than the second but the second would deliver much better results.The MAH and the VMD must keep up to date with all relevant information in order to fulfil the following responsibilities: On the other hand number of droplet per millilitre is a very poor measure. Low VMD are often heavily influenced by high driftables. The first chart has 43% driftables whereas the second has only 6%.ĭriftable: In this context driftables are the percentage of the spray volume that contains droplets smaller than 100 micron and which almost certainly will not reach their target: Wasted spray. As shown in the above example where the first has a RS of 2.15 and the second has 1.15 the nearer to 1.0 the better.ĭriftables is another good measure. ![]() As with VMD, D and D are diameters representing the points at which 10%, and 90% of the volume of liquid sprayed is in droplets of smaller diameter the relative span is defined as the D minus the D and then divided by the VMD (D). The efficiency of a spray nozzle is inversely proportional to the range of droplets it emits. The most reliable statistic is probably relative span, which is a dimensionless parameter calculated from the volume distribution only. ![]() ![]() So we need more information to tell which nozzle to use other than VMD.
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