Vet360 Vol 4 Issue 3 June 2017 Vet360 - Page 20

CPD ACCREDITED ARTICLE 3500 When the GIT of man is compared to animals, there are major difference that can influence absorption between the species. These difference may be ana- tomical in that there are different structure of the GIT; there may be difference in transit times; difference in content and thus non-specific binding; differences in bile salts; differences in pH amongst the different ar- eas; differences in GIT bacterial content and/or spe- cies; differences in liver metabolic capacity; and most importantly differences in the transport proteins in the intestinal wall. The latter is also a major reason why veterinary drugs differ so much between species. To illustrate the process, the innovator veterinary for- mulation of amoxycillin-clavulanate and Ran-Clav® (Ranbaxy) were compared at the same dose and the same route in the same six Beagles (in a cross-over study undertaken by myself). (Figure 4) The result for amoxycillin phase of the study showed a marked dif- ference in absorptive profile between the two formu- lations. While the small sample size did result in signif- icant variability in both groups, this was much more substantial (>80%) in the Ran-Clav® group. This study illustrates the point that the non-veterinary formula- tion could not only differ in the extent of absorption, but more importantly could result in large intra-sub- 3000 2500 Another important scenario that comes up in South Africa is the cost of the medication. Under some con- ditions veterinary medications may be more expen- sive than their medical generics, due to lower costs on the medical side from larger scale production. Can one use these human generics as cheaper therapeu- tic options? Firstly legally, the onus is on the treating veterinarian to let the owner know that there is a vet- erinary formulation and give them the option. The reason for this, is that the medical product has been tested in only people and thus the veterinary profile may be unknown i.e. it may be possible that the drug has different profiles in the veterinary patient than in people. 2000 1500 1000 500 0 0 2 4 6 8 10 12 14 Time (h) Figure 4: Average plasma concentration versus time profile for amoxycillin for a veterinary (R) and non-veterinary (T) amoxy- cillin formulation tested in the same group of six dogs in a 2x2 cross over study. ject variability which could mean completely inferior treatment in some individuals. This effect is addition to being potential dangerous, is also generally un- known until tested. Conclusion Drug regulation science, is a highly complex science that is focused on allowing the treating veterinarian the best chance of getting therapeutic success in a patient with the least chance of formulation failure. This science extends to both innovator and generic formulations, but only so far as to the species and in- dication for which the product has been tested. As such, when using a non-veterinary formulation, care should be practiced, as therapeutic success are affect- ed by a number of unknown variables such as added exipients and exact structure of the active chemical/ ingredient. ANSWER the questions on the Vet360 App. Available from the Itunes/Play store! Use your App to answer the questions. Your certificate can be found on www.vet360.vetlink.co.za if you log in with youÇApp username and password. Or for a web based system visit: http://www.cpdsolutions.co.za/?re=on- linevets CPD facility for Vet360 Subscribers Category Use Benefits Dangers Liabilities Innovator Vet Medi- cine/Stock Remedy Registered Use Proven safety, quality and efficacy Poor storage can change product safety If used and stored as per instruc- tions: Falls to the manufacturer Generic Vet Medi- cines/Stock Remedies Registered Use Proven safety, quality and efficacy Poor storage can change product safety If used and stored as per instruc- tions: Falls to the manufacturer Stock Remedies: Vet Med (innovator or ge- neric) used extralabel Used for non-regis- tered purpose in the intended species Proven quality. Safety knoen in target species if used at the recom- mended dose Unknown efficacy when used for a new indication and potentially safety concerns when used at a different dose Vet liable for extralabel use, since use is in the intended species i.e. species saftety usually known Stock Remedies: Vet Med (innovator or ge- neric) used extralabel Used for non-regis- tered purposes in a non-indicated species Quality of the product proven Unknown efficacy as used for a new indication, and unknown safety con- cerns as used in untested species Vet liable for extralabel use. Risk increases as species safety usual- ly unknown Human Meds Non-registered use Quality of the product proven Unknown efficacy and safety Vet liable for extralabel use. Risks are the same as use of a veter- inary medicine in non-indicated species Compound Meds Non-registered prod- uct Patient specific treat- ment option when no registered product is available Unknown safety, efficacy and quality Vet liable for use. Greater risk than extrlabel use, since quality, safety and efficacy unknown Table 2: Indication of how personal liability increases as different categories of medicines are used vet360 Issue 03 | JUNE 2017 | 20