Pexion is a new drug used to control epileptic fits (seizures) in dogs. The active ingredient is called imepitoin and it is thought to have reduced side effects and therefore possibly be safer than the standard traditional treatments. Pexion is given twice daily and acts rapidly to control seizures. It begins working in a few hours and after about 3 days a steady state has been achieved. This helps your vet to find the correct dose for your dog, which always takes a little while to be evaluated for any particular patient. The aim is to find the lowest dose which will reduce the frequency of fits to zero or to a very low level.
It can be found that some dogs will have a slight increased thirst or hunger, or be slightly sedated when they first start taking Pexion. These effects are usually less obvious when compared with other treatments, and tend to disappear anyway once a dog has adjusted to being on regular medication. Pexion does not cause the liver damage which has sometimes been associated with other treatments. Due to the mode of excretion, Pexion is also safe for animals with reduced kidney function.
White, oblong, half-scored tablets with embedded logo “I 01” (100 mg) or “I 02” (400 mg) on one side. The tablet can be divided into equal halves.
For the reduction of the frequency of generalised seizures due to idiopathic epilepsy in dogs for use after careful evaluation of alternative treatment options.
Oral administration at a dose range of 10 mg to 30 mg imepitoin per kg bodyweight twice daily, approximately 12 hours apart. Each tablet can be halved for appropriate dosing according to the individual bodyweight of the dog. Any remaining half-tablet should be used for the next dose.
The required dose will vary between dogs and will depend on the severity of the disorder. The recommended initial dose of imepitoin is 10 mg per kg bodyweight twice daily.
Initiate therapy using the bodyweight in kg and the dosing table. If seizures are not adequately reduced following a minimum of 1 week of treatment at the current dose the supervising veterinary surgeon should re-assess the dog. Assuming that the veterinary medicinal product is well tolerated by the dog, the dose can be increased by 50 to 100% increments up to a maximum dosage of 30 mg per kg administered twice daily.
Bioavailability is greater when administered to fasted dogs. The timing of tablet administration in relation to feeding should be kept consistent.
Number of tablets (to be given twice daily) for initiation of treatment (see table 1)
Table 1: Number of tablets (to be given twice daily) for initiation of treatment
Number of tablets
2.0 - 5.0
15.1 - 20.0
20.1 - 40.0
40.1 - 60.0
Do not use in case of hypersensitivity to the active substance or to any of the excipients. Do not use in dogs with severely impaired hepatic function, severe renal or severe cardiovascular disorders.
The pharmacological response to imepitoin may vary and efficacy may not be complete. Nevertheless imepitoin is considered to be a suitable treatment option in some dogs because of its safety profile. On treatment, some dogs will be free of seizures, in other dogs a reduction of the number of seizures will be observed, whilst others may be non-responders. In non-responders, an increase in seizure frequency may be observed. Should seizures not be adequately controlled, further diagnostic measures and other antiepileptic treatment should be considered.
The benefit/risk assessment for the individual dog should take into account the details in the product literature.
The efficacy of the veterinary medicinal product in dogs with status epilepticus and cluster seizures has not been investigated. Therefore, imepitoin should not be used as primary treatment in dogs with cluster seizures and status epilepticus. Transition to other types of antiepileptic therapy should be done gradually and with appropriate clinical supervision.
No loss of anticonvulsant efficacy (tolerance development) during continuous treatment of 4 weeks was observed in experimental studies lasting 4 weeks.
Special precautions for use in animals: The safety of the veterinary medicinal product has not been tested in dogs weighing less than 5 kg or in dogs with safety concerns such as renal, liver, cardiac, gastrointestinal or other disease. The efficacy as an add-on therapy has not been demonstrated. Mild behavioural or muscular signs may be observed in dogs upon abrupt termination of treatment with imepitoin.
Special precautions to be taken by the person administering the veterinary medicinal product to animals: In case of accidental ingestion especially by a child, seek medical advice immediately and show the package leaflet or the label to the physician. To prevent accidental ingestion of tablets, the cap of the bottle should be replaced immediately after withdrawing the required number of tablets for one administration.
The following mild and generally transient adverse reactions have been observed in pre-clinical and clinical studies (in order of decreasing frequency): In rare cases polyphagia was reported at the beginning of the treatment, also hyperactivity, polyuria, polydypsia, somnolence, hypersalivation, emesis, ataxia, apathy, diarrhoea, prolapsed nictitating membrane, decreased sight and sensitivity to sound.
A mild elevation in plasma creatinine and cholesterol levels has been observed in dogs treated with imepitoin; however these did not exceed the normal reference ranges and were not associated with any clinically significant observations or events.
The use of the veterinary medicinal product is not recommended in male breeding dogs or in female dogs during pregnancy and lactation.
The product has been used in combination with phenobarbital in a small number of cases and no harmful clinical interactions were observed.
In case of repeated overdose of up to 5 times the highest recommended dose, central nervous system (CNS), gastrointestinal-related effects and reversible prolongation of the QT interval have been noted. At such doses, the symptoms are not usually life-threatening and generally resolve within 24 hours if symptomatic treatment is given.
These CNS effects may include loss of righting reflex, decreased activity, eyelid closure, lacrimation, dry eye and nystagmus.
At 5 times the recommended dose, decreased bodyweight may be observed.
In male dogs administered 10 times the upper recommended therapeutic dose, diffuse atrophy of seminiferous tubules in the testes and associated decreased sperm counts were seen.
Any unused veterinary medicinal product or waste materials derived from such veterinary medicinal products should be disposed of in accordance with local requirements.
For animal treatment only.
Keep out of the sight and reach of children.
This veterinary medicinal product does not require any special storage conditions.
Bottle of 100 or 250 tablets. Not all pack sizes may be marketed.
Imepitoin is a centrally acting antiepileptic substance which crosses the blood brain barrier without involvement of active transport or active clearance, resulting in immediate equilibrium between plasma and brain. Here it acts as a low affinity partial agonist of the benzodiazepine receptor. Imepitoin inhibits seizures via potentiation of the GABAA receptor-mediated inhibitory effects on the neurons. In addition, imepitoin has a weak calcium channel blocking effect which may contribute to its anticonvulsive properties. In a European field trial that compared the efficacy of imepitoin to phenobarbital in 226 dogs with newly diagnosed idiopathic epilepsy, 45% of cases from the imepitoin group and 20% from the phenobarbital group were excluded from the efficacy analysis for reasons that included failure to respond to treatment. In the remaining dogs (64 dogs for Pexion and 88 dogs for phenobarbital), the following clinical results were observed: Mean frequency of generalised seizures was reduced from 2.3 seizures per month in the imepitoin group and from 2.4 seizures per month in the phenobarbital group to 1.1 seizures per month in both groups after 20 weeks of treatment. The difference between imepitoin and phenobarbital groups in the seizure frequency per month after treatment (adjusted for baseline difference) was 0.004, 95% CI [-0.928, 0.935]. During the evaluation phase of 12 weeks, the proportion of generalised seizure-free dogs was 47% (30 dogs) in the imepitoin group and 58% (51 dogs) in the phenobarbital group. The safety of both treatments was evaluated in the full analysis data set (or safety data set, i.e. 116 animals in the imepitoin group and 110 animals in the phenobarbital group). Increasing doses of phenobarbital were associated with increasing levels of the liver enzymes ALT, AP, AST, GGT, and GLDH. In comparison, none of the five enzymes increased with increasing doses of imepitoin. A slight increase in creatinine values compared to baseline was observed in the imepitoin-treated dogs. However, the upper limit of the confidence interval for creatinine remained within the reference range at all visits. Additionally, fewer adverse events were noted for polyuria (10% vs 19% of dogs), polydipsia (14% vs 23%) and marked sedation (14% vs 25 %) when comparing imepitoin to phenobarbital.
Absorption Pharmacokinetic studies indicate that imepitoin is well absorbed (> 92 %) after oral administration and that no pronounced first pass effect occurs. After oral administration of imepitoin tablets at 30 mg/kg without food, peak blood concentrations are attained rapidly with a Tmax of around 2 hours, a Cmax of about 18 µg/ml. Co-administration of imepitoin tablets with food, reduces the total AUC by 30% but produces no significant change in Tmax and Cmax. Gender-specific differences do not occur.
Distribution Dose linearity occurs over the therapeutic dose range of imepitoin. Imepitoin has a relatively high volume of distribution (579 to 1548 ml/kg). The in-vivo plasma protein binding of imepitoin in dogs is low (60 to 70%). No interaction with highly protein bound compounds is therefore expected. No accumulation of imepitoin in plasma occurs after repeated administration, once steady state is reached.
Metabolism Imepitoin is extensively metabolised prior to elimination. Metabolite profiles in urine and faeces revealed four major inactive metabolites which are formed by oxidative modification.
Elimination Imepitoin is rapidly cleared from blood (Cl = 260 to 568 ml/hours/kg) with an elimination half-life of approximately 1.5 to 2 hours. The majority of imepitoin and its metabolites are excreted via the faecal route rather than the urinary route so that no major change in pharmacokinetics and no accumulation is expected in renally impaired dogs.
Boehringer Ingelheim Vetmedica GmbH
EU/2/12/147/001 100mg x 100 tablets.
EU/2/12/147/002 100mg x 250 tablets
EU/2/12/147/003 400mg x 100 tablets
EU/2/12/147/004 400mg x 250 tablets
Pexion 100 mg tablets for dogs - 5012917030068
Pexion 400 mg tablets for dogs - 5012917030075
All prices include VAT where applicable.
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Below are some recent questions we've received regarding Pexion Tablets for Dogs, including answers from our team.
How many months on a repeat prescription for pexion
How much treatment is allowed on a prescription for Pexion is pretty much down to your vet. Most vets will write out a prescription which allows for 3 - 6 months worth of medication. Some will only allow a month, some will put repeats on the prescription which will go on for much longer. It is down to your vet. We can only supply what has been authorised.