High doses and withdrawal periods
The administration of medicines to production animals is subject to a withdrawal period, during which products derived from the animal concerned must not be supplied as foodstuffs. The withdrawal period is determined through studies, where the largest permissible doses are administered. The estimates take into account the possible risks associated with the medicines and considerable safety margins apply.
What happens if I need to administer more than the recommended dose? Is it possible that it increases the withdrawal period? Should I increase the withdrawal period?
In short, the answer is yes – but the exact course of action should be determined by a vet. For example, if you are using penicillin injection to treat mastitis, a considerably longer withdrawal period is needed.
Similarly, your vet should advise you on the best course of action if the treatment continues for longer than normal or if the medicine is administered differently from what is specified in the instruction leaflet. Unfortunately, there is no one-size-fits-all rule to adjusting the withdrawal period as no scientific evidence exist on non-standard dosages.