MDR1 gene: what is important to know?
MDR1 (Multi-Drug Resistance 1) is a gene in dogs that is responsible for the intolerance of certain drugs. The product of the MDR1 gene is P-glycoprotein, a component of the blood-brain barrier. When it is damaged, various substances can penetrate the dog's brain and not be removed. In this case, some medications can be particularly dangerous.
Normally, this barrier reliably protects the brain from toxic substances circulating in the blood. However, in Australian Shepherds and many other breeds, this "filter" does not do its job due to a genetic defect. As a result, drugs that are completely safe for a normal dog, in the case of dogs with the MDR1 mutation, freely overcome this barrier, accumulate in brain structures and cause severe poisoning.
The most dangerous are drugs from the group of macrocyclic lactones, which are most often used to combat parasites. The well-known ivermectin, as well as moxidectin, doramectin and selamectin, when entering the body of such a dog, can provoke the rapid development of neurological disorders. At first, you may notice profuse salivation, tremors or a shaky gait, but the condition worsens very quickly.
Also on the list of potentially dangerous drugs are some anti-diarrhea drugs, in particular loperamide.
1. Протипаразитарні засоби
Ці препарати використовуються для боротьби з глистами, блохами та кліщами.
Ivermectin (Івермектин)
Selamectin (Селамектин)
Milbemycin (Мільбеміцин)
Moxidectin (Моксидектин)
Abamectin (абамектин)
Doramectin (дорамектин)
Metronidazole (Метронідазол)
Emodepside (емодепсид)
2. Засоби для наркозу, седації та знеболення
Препарати, що впливають на центральну нервову систему.
Acepromazine (Ацепромазин)
Butorphanol (Буторфанол)
Buprenorphine (Бупренорфін)
Morphine (Морфін)
Fentanyl (Фентаніл)
Phenothiazines (Фенотіазини)
3. Хіміотерапевтичні та онкологічні препарати
Використовуються для лікування злоякісних новоутворень.
Vincristine (Вінкристин)
Vinblastine (Вінбластин)
Vindesine (віндезин)
Vinorelbine (винорелбін)
Doxorubicin (Доксорубіцин)
Dactinomycin (дактиноміцин)
Paclitaxel (Паклітаксел)
Etoposide (Етопозид)
Mitoxantrone (Мітоксантрон)
4. Шлунково-кишкові засоби (протидіарейні та протиблювотні)
Loperamide (Лоперамід)
Metoclopramide (Метоклопрамід)
Domperidone (Домперидон)
Ondansetron (Ондансетрон)
Apomorphine (Апоморфін)
Cimetidine (Циметидин)
Ranitidine (Ранітидин)
5. Антибіотики та протигрибкові засоби
Doxycycline (Доксициклін)
Erythromycin (Еритроміцин)
Grepafloxacin (Грепафлоксацин)
Sparfloxacin (Спарфлоксацин)
Tetracycline (Тетрациклін)
Rifamicin (Рифаміцин)
Ketoconazole (Кетоконазол)
Itraconazole (Ітраконазол)
6. Серцево-судинні та гормональні препарати
Digoxin (Дигоксин)
Diltiazem (Дилтіазем)
Verapamil (Верапаміл)
Chinidin / Quinidine (Хінідин)
Losartan (Лозартан)
Dexamethasone (Дексаметазон)
Hydrocortisone (Гідрокортизон)
Methylprednisolone (Метилпреднізолон)
Cortisol (Кортизол)
Aldosterone (Альдостерон)
Estradiol (Естрадіол)
7. Інші (імуносупресори, антидепресанти та ін.)
Cyclosporin A (Циклоспорин А)
Tacrolimus (Такролімус)
Amitriptyline (Амітриптилін)
Ebastine (Ебастин)
Fexofenadine (Фексофенадин)
Phenytoin (Фенітоїн)
PS Data on the dangers of drugs vary greatly - depending on the source, some materials categorically prohibit almost all drugs, some allow them in reduced doses.
The best way to protect your Australian Shepherd is to have it tested for genetics. Since this mutation is hereditary, a single test will give you a complete picture of your dog's health for life. You will know if your dog is a carrier of this defect and can take preventive measures.
However, it is important to understand that genetic testing results are not a complete guarantee of safety. There is empirical evidence that even dogs that are MDR1-clear sometimes show signs of toxic reactions to certain drugs. Laboratories are also wrong. This suggests that other, as yet poorly understood, genetic mechanisms may be responsible for drug sensitivity, for which there are currently no specific tests. Therefore, one should not rely solely on genetic testing: it is important to closely monitor the health of the dog and always discuss the possible risks of using certain drugs with a veterinarian.
If the mutation is confirmed, you should make this knowledge part of your routine: always warn the veterinarian about your Aussie's peculiarity before any appointment. For every "dangerous" substance today, there are effective and safe analogues that your doctor will be able to choose without any risk to the animal.
Remember that awareness is the most effective tool of protection. Do not self-medicate and never use antiparasitics or other drugs "on the eye" without consulting a specialist who knows the specifics of Australian Shepherds.