The induction of emesis in dogs

Transcription

1 Swallowing Dangerss The induction of emesis in dogs Swallowing Dangers TM SWALLOWING DANGERS TM TM

2 Latest thinking In recent years, further development has gone into the induction of emesis in dogs. This technical manual, from Forum Animal Health, has been created to summarise current thinking, existing treatments and new recommended practice guidelines including dosage recommendations, for veterinary practitioners and nursing staff who come into contact with situations requiring emesis. Recognising both the need to present technical and medical information, as well as broader stewardship of the complexities of this area. Termed, Swallowing Dangers, we hope that you find this manual informative, and that elements can be transferred to help educate dog owners. Resolving Swallowing Dangers All dogs, of all ages, can, and often do ingest things they shouldn t. Such occurrences are common situations for most small animal veterinary surgeries. Treatment can be diverse ranging from admission of dog but wait and monitor, endoscopy and remove, use salt water, soda or apomorphine to induce emesis, or in some cases, surgery. It s acknowledged that more could be done to reduce harm to dogs and potentially fatal poisoning; if dog owners understood the risks more clearly and responded by getting their dog to the vet without delay. Further, with client education and awareness programs incidences of swallowing dangers could be reduced. Identifying Swallowing Dangers There are three categories of Swallowing Dangers 1. Foreign Bodies these are inert objects that dogs swallow, often after chewing or at play. 2. Toxic Products these are naturally corrosive and will damage oesophagus, stomach and gut lining. 3. Poisons these cause damage when digested and damage various body organs and systems. The veterinary surgeons treatment for Swallowing Dangers will be dependent on the harmful substances ingested. The main poison groups and the percentage incidence in the USA are indicated below; VPIS lists commonly presented UK poison ingestions; however this USA data ranking and categorisation and may be helpful in educating owners on the breadth of possible dangers. 43% Human Medicine 16% Human Foods, e.g. chocolate, grapes, raisins 7.5% Insecticide 6.5% Rodenticide 5.5% Dietary Supplements & Vitamins 1 Apometic the only licenced veterinary Apomorphine 2 Traditionally, human Apomorphine has been used by vets under cascade to avert some poisons in swallowing dangers. Today newly launched Apometic is the only licensed treatment on the market to induce emesis in dogs. PAGE 2

3 Pharmacodynamic properties Apomorphine is a synthetic derivative of morphine with no analgesic, opiate or addictive properties. At low doses, apomorphine induces emesis by stimulation of the dopamine receptors in the chemoreceptor trigger zone (CTZ). How Apomorphine works Higher doses of apomorphine, however, may suppress vomiting by stimulating the μ receptors in the vomiting centre in the brain. It may lower blood pressure and body temperature and increase heart rate but these effects are transient. It may also increase cortisol levels, reduce gastrin and insulin levels but these effects disappear within minutes. Pharmacokinetic properties Absorption After subcutaneous administration apomorphine is rapidly absorbed. Concentrations sufficient to induce emesis in the dog are achieved during the first 3-10 minutes and peak plasma concentrations are achieved in 20 to 25 minutes. Distribution Apomorphine is lipophilic and it penetrates tissues well. Diffusion across the bloodbrain barrier is rapid after injection. Metabolism Apomorphine is extensively metabolised by the liver into non active metabolites. Excretion The metabolites and very little unchanged apomorphine (<2%) are excreted via the urine. The half-life of apomorphine in dogs is minutes. Today, Apometic is the only apomorphine-based product licensed in the UK to induce emesis in dogs. In the past, many vets will have used the human version of Apomorphine under cascade and established their own favored route of administration. Apometic is licensed for administration by subcutaneous injection; this is found, universally, to be the easiest route. There could alternative routes of administration used in other countries. Apomorphine proved to be more effective as an emetic in dogs after subcutaneous administration than after intramuscular injection (Scherkl et al., 1990). Introducing Apometic PAGE 3

4 Apometic Dose Previous BSAVA Formulary and BSAVA poisons guide have given differing dosage guidance, which has lead to some confusion. This is because the data presented in the BSAVA Formulary is not a critical review of published data. Rather BSAVA have identified published papers and indicated the dose range cited in these papers. Forum Animal Health has carried out a thorough review of all peer reviewed papers to confirm that the most efficacious dose is 0.2mg/kg by subcutaneous injection. Furthermore this has also confirmed by an independent clinical expert. Apometic contains 10mg/ml Apomorphine Hydrochloride. The dose to induce emesis is indicated at 0.2mg/kg please follow the guide below: Body weight (kg) Dose (ml) If emesis is not induced by a single dose, following the guide above, repeat injections will also prove ineffective and should not be given. In the case of a potential poisoning, emesis should be induced within 2 hours of consumption of the poison. This ensures that the poison is not fully digested and reduces the likelihood of longterm supportive care or organ damage. Precautions Apomorphine should not be used on dogs with increased risk of aspiration such as hypoxia, dyspnea, those in shock, seizuring, comatose or with deteriorating CNS function. Apomorphine should not be used to treat ingestion of caustics, including strong acids or alkali. This is due to increased injury from re-exposure of the oesophagus and gastric mucosa. The use of emetics after ingestion of CNS stimulants such as strychnine may precipitate seizures. Petroleum distillates ingestion carries an increased risk of aspiration when emetics are used. Clinical judgment should be exercised regarding the risk of aspiration weighed against the risk of toxicity. Apomorphine should not be used in animals with decreased liver-function.apomorphine should not be used in: cats, rabbits or rodents Apomorphine should not be used in cases where gastric foreign bodies may be present. Veterinarians may have experience of using Apomorphine to induce emesis in a wider number of situations and they should continue to use their clinical judgement on a case by case basis as issues present. PAGE 4

5 Apomorphine should not be used to treat ingestion of CNS-depressant drugs such as opiates or barbiturates; or on animals that are known to be hypersensitive to morphine and related drugs. Beware Drug Interactions Anti-emetic drugs such as phenothiazines may decrease the effectiveness of Apomorphine. An Apomorphine overdose can cause respiratory and cardiac depression, CNS stimulation or depression and protracted vomiting. Naloxone may be used to reverse CNS and respiratory signs, but will not diminish the vomiting. Overdose In the absence of a licensed product to induce emesis, under cascade veterinarians have previously used washing soda crystals or concentrated salt water. Neither of these has proven to be as effective in inducing emesis. Full emesis has been induced using Apometic after washing soda only led to partial stomach emptying. We would recommend that clients are educated in the presentation of potential Swallowing Dangers to the practice within the two-hour window, the aim being to increase prompt client action. Furthermore pet owners should be discouraged from attempting to induce emesis, as home administration can lead to increased risk of harm. It s critical that dog owners act with urgency as the dangers of delay to the animal s health can be fatal. In the case of poisoning and toxic ingestion it is important to identify the product and active; so ensure the client brings packages or samples when they present to surgery. Non-Licensed Solutions Beware of owner inaction In a crisis event it is difficult for pet owners to recall accurately, things like time since ingestion, the item details, and the exact quantity ingested. Experience of vets polled (3) indicates many events where larger quantities of poisons were emitted compared to the amount reported by the client. A prudent approach would be to consider any amount of a known poison to be a risk. The LD50 of theobromine is reportedly mg/kg, but severe signs and deaths may occur at much lower dosages, and individual sensitivity to methylxanthines varies. In general, mild signs (vomiting, diarrhea, polydipsia) may be seen in dogs ingesting 20 mg/kg, cardiotoxic effects may be seen at mg/kg, and seizures may occur at dosages 60 mg/kg. One ounce of milk chocolate per pound of body weight is a potentially lethal dose in dogs. (4) Theobromine in chocolate poses a poisoning risk so encourage owners to present without delay. There are many brands of chocolates with very varying levels of theobromine in them so it is impossible to be certain of intake. Levels of Theobromine are not currently declared on UK packaging or disclosed on company websites. When an owner says the dog has eaten milk chocolate, do not assume it is safe. Regardless of the quantity or type of potentially poisonous substances reported to be ingested, induction of emesis should be one of the treatments considered as it could save a dog s life. PAGE 5

6 Poisons Clinical signs The following products are potentially dangerous to dogs. Product Chemical/Name Clinical Signs Chocolate theobromine Agitation, hyperexcitability, tremors, convulsions and problems with the heart. NSAID ibuprofen, Vomiting, diarrhoeagastric ulceration and diclofenac kidney failure Rodenticides bromadiolone, difenacoum and warfarin Excessive bruising or bleeding and effects may not appear for several days Slug/snail Metaldehyde Unsteady on their feet and twitchy, pellets but may rapidly deteriorate and suffer continuous convulsions and possibly respiratory failure. Grapes, Vitis Vinifera Kidney failure raisins, sultanas, currants Vitamin D Vomiting, diarrhoea, bleeding from the gut, convulsions, abnormal heart rhythm and kidney failure Onions Thiosulphate Onion poisonous and causes Heinz body anaemia. The haemolytic episode usually occurs several days after onion ingestion (lowest haematocrit around day 5 post ingestion). Further feeding of onions will have a cumulative effect. PAGE 6

7 When presented with a swallowing event it is important to establish what has been ingested, when it was and how much. Is it a poison Is it caustic Is it a foreign body Guidance for the management of Swallowing Dangers YES YES YES Is it a neurostimulant or neuro deppressant Consider stomach lavage & Charcoal Has it entered the stomach NO YES YES NO < 2 hours since ingestion Start supportive therapy based on poison Monitor Consider surgical removal Consider endoscopy YES < 2 hours since ingestion NO YES Administer Apometic YES NO Has full emesis occured YES Monitor patient PAGE 7

8 Pet owner awareness From consumer surveys it is clear there is a low level of pet owner knowledge surrounding Swallowing Dangers. (Footnote 5) When asked name ten dog poisons the average response was 2.5. In response to what would you do if your dog swallowed a [named poisonous item] only 30% of those asked would present to the vet practice immediately. 40% said they would wait for sign of illness. As all vet care professionals are aware, early presentation is essential in ensuring a happy outcome. Client Education All members of a practice can help in educating pet owners. This has three benefits: Fewer pet deaths Informed pet owners Prolonged quality of life following a swallowing danger The use of waiting room posters, practice seasonal displays, newsletters and advice sheets will offer good routes to inform clients. More active events, such as puppy parties, nurse clinics can be very productive. The main points to convey to pet owners are: Three categories of Swallowing Dangers : Toxic, through caustic such as bleach Foreign bodies, toys, bones, sticks etc. Poisons - most common being bait, chocolate, pills and grapes. Early action is the key to a satisfactory outcome. Best advice for owners is to feed specifically formulated dog food to avoid accidental ingestion of anything harmful (which could be included in human food) its best to feed dog food suitable for their digestive system. Get your pet to the surgery within 2 hours, if you see it eating anything it should not do. Owner Action In case of emergency, the following four steps should be taken: 1. Prevent the dog from eating any more of the toxin or poisons 2. Phone the vet and take advice 3. Collect all available packaging from the ingested food/products etc. and show vet 4. Drive dog to the vet, keeping it calm and cool Below is a sample newsletter article: At [your surgery] we are often surprised by the things dogs eat. It s not just stealing naughty treats or helping themselves from the dinner table, we call these events Swallowing Dangers. The reason is every year many dogs suffer in pain, permanent damage to body organs, and, in some cases, fatally from swallowing the wrong thing. There are three classes of Swallowing Dangers: Toxins: these are corrosive such as anti-freeze, which will burn the oesophagus. For toxins we need to mop up as quickly as possible inside the pets stomach, we will pump the stomach and in some cases have to operate. Foreign bodies: these can be small objects such as toy balls, chicken bones, building blocks. Or larger miss shaped objects such as toy cars, rubber ducks (oh yes we have seen it all) or clothing. In these cases we nearly always need to go in and remove it. PAGE 8

9 Poisons: these can be common every day items found around the home Many of them you eat every day in your normal daily diet. Chocolate, grapes, onions, medicines like headache pills and even health food supplements contain dog poisons. Clearly things like rat bait, slug and snail pellets and weed killers will be poisonous. With all Swallowing Dangers it is important to get to the clinic as soon as you can. it could save the life of your pet. Remember, the following four steps: 1. Prevent the dog from eating any more of the poison 2. Phone the practice [number] immediately 3. Collect any packaging 4. Get to the surgery as quickly as possible Ask any member of our team for help on what to avoid and ask for our fact sheet. Consider keeping your pet insured PAGE 9

10 DATA SHEET Apometic 10mg/ml Solution for Injection Introduction Company name: Forum Animal Health Address: Betchworth House, Station Road, Redhill, Surrey RH1 1DL Telephone: Fax: Website: Presentation Apometic solution for injection contains 10mg/ml apomorphine hydrochloride as a clear, colourless or almost colourless solution. Uses Apometic is indicated to induce emesis in dogs that have, or are suspected to have, ingested substances that may be poisonous. Dosage and administration Dogs: 0.2 mg per kg bodyweight (0.02 ml/kg bodyweight), by subcutaneous injection. Weigh animals before treatment. Use a 1ml syringe graduated to 0.01ml to facilitate accurate dosing The dosing chart below is intended as a guide. Body weight (kg) Dose (ml) Contra-indications, warnings, etc Do not use in cases of depression of the central nervous system. Do not use in cats and other species. Do not use in cases of caustic poisoning or where gastric foreign bodies may be present. Do not use in cases of poisoning due to pyrethroids Do not use in animals known to be hypersensitive to apomorphine or any other excipients. Do not exceed the recommended dosage. Emesis occurs rapidly (within 10 minutes). If emesis is not induced following a single injection, repeated injections will also prove ineffective and should not be given. Use of the product is not recommended if the poison was ingested, or suspected to be ingested, more than 2 hours previously. The use of the product in cases of known or suspected hepatic impairment should be in accordance with a risk/benefit assessment by the responsible veterinarian. Side-effects: Adverse effects include hypotension, drowsiness and/or sedation, dyskinesia and protracted vomiting. The decrease in blood pressure is dose-dependent. The maximum decrease in blood pressure is normally reached after 5 minutes following i.v. dose and the blood pressure returns to basal level after 10 to 30 minutes. PAGE 10

11 No data are available on use during pregnancy, lactation or lay. Use only according to the benefit/risk assessment by the responsible veterinarian. In the absence of compatibility studies, apomorphine must not be mixed with other veterinary medicinal products. Operator warnings: Avoid accidental self-injection. In case of accidental self-injection, seek medical advice immediately and show the package leaflet or label to the doctor. Avoid contact with skin and eyes. In case of contact with skin or eyes, rinse immediately with fresh water. Pharmaceutical precautions Do not store above 25 C. Store in the original package to protect from light. The solution should be inspected visually prior to use. Only clear and colourless solutions should be used. For single use only. Any unused solution should be discarded. Dispose of any unused product and empty ampoules in accordance with guidance from your local waste regulation authority. Keep out of reach of children. For animal treatment only. Legal category POM-V Packaging Quantities Clear glass ampoules containing 2 ml solution for injection. Further Information Dopamine antagonists (e.g. phenothiazines) may negate the emetic effect of apomorphine. Overdose may result in respiratory and/or cardiac depression, CNS stimulation or depression and protracted vomiting. Doses of 0.4 mg/kg mg/kg administered intravenously in dogs resulted in a short period of sedation followed by incessant running lasting from ½ to 1 hour from which the animals recovered. Naloxone may reverse the respiratory and CNS effects of the product but not the emetic effects. This is a limited Marketing Authorisation. A full set of supporting efficacy data is not available for this product. All suspected adverse reactions and any suspected lack of efficacy should be reported to at Forum Animal Health, Betchworth House, Station Road, Redhill, Surrey RH1 1DL. Further information on this product and its supporting data can be found on Marketing authorisation number Vm 05928/4006. GTIN Apometic 2ml (5x2ml) Ampoule PAGE 11

12 REFERENCES 1. Accessed November Apometic the only licensed veterinary Apomorphine available in the UK November Vet Survey South East UK August 2013 (data on file) 4. Accessed November Forum Group Pet Owners Survey August September 2013 (data on file) About Forum Animal Health Forum Animal Health has been developing and marketing animal health products for over 20 years. By working closely with veterinary experts, Forum Animal Health offers fresh and innovative health solutions for livestock, small animals and equine. Forum Animal Health is a member of the National Office of Animal Health (NOAH), the United Kingdom s animal health trade association, and is a signatory to its Code of Practice for the Promotion of Animal Medicines. Apometic contains 10mg/ml apomorphine hydrochloride for induction of emesis in dogs. POM-V. Adverse effects include hypotension, drowsiness and/or sedation, dyskinesia and protracted vomiting. Precautions: Use of the product is not recommended if the poison was ingested, or suspected to be ingested, more than 2 hours previously. The use of the product in cases of known or suspected hepatic impairment should be in accordance with a risk/benefit assessment by the responsible veterinarian. Warnings: Do not exceed the recommended dosage. Emesis occurs rapidly (within 10 minutes). If emesis is not induced following a single injection, repeated injections will also prove ineffective and should not be given. Contraindications: Do not use in cases of depression of the central nervous system. Do not use in cats and other species. Do not use in cases of caustic poisoning or where gastric foreign bodies may be present. Do not use in cases of poisoning due to pyrethroids Do not use in animals known to be hypersensitive to apomorphine or any other excipients. Further information available from Forum Animal Health, Betchworth House, Station Road, Redhill, Surrey, RH1 1DL. Use medicines responsibility Consult your veterinary surgeon for further advice. Forum Animal Health Crown House, 2 8 Gloucester Road, Redhill, Surrey, RH1 1FH, UK Tel V1.0 date 18/11/13Swallowing Dangers is a Trade Mark of Forum Products Limited