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Corvental-D Capsules for Dogs

  • 100mg » Priced per Capsule £0.95
  • 200mg » Priced per Capsule £1.22
  • 500mg » Priced per Capsule £2.39

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Corvental-D capsules are given to dogs to treat congestive heart failure and bronchitis. Most commonly they are prescribed by vets for chronic wheezing and coughing associated with lower airway disease, which is more common in small terrier breeds of dog. A significant improvement in respiratory function can be seen.
Treatment is normally given once daily with food. Dogs to be treated should be weighed so that an accurate dose of Corvental-D can be calculated and given.

Corvental-D is a slight stimulant to the nervous system and can be associated with restlessness and excitement if overdosed. It is sometimes advised not to give Corvental-D immediately before a general anaesthetic. If vomiting occurs, the dose should be reduced in future, or treatment should be stopped.


CorventalD Capsules are hard gelatin capsules containing either 100 mg, 200 mg or 500 mg Theophylline Ph.Eur. in a sustained release ``Divido' presentation. The capsules are coloured and sized, according to active ingredient content

Corvental D 100 mg: blue and white (small capsule)

Corvental D 200 mg: green (small capsule)

Corvental D 500 mg: green (large capsule)


For the treatment of bronchitis and congestive heart failure in dogs.

Dosage and administration

20 mg per kg bodyweight to be administered orally once daily.

Care should be taken to ensure that dogs are weighed carefully and accurately and the dose does not exceed 20 mg/kg bodyweight.

Contra-indications, warnings, etc

Do not use in dogs with a known history of epileptiform seizures as convulsions have been reported in patients on theophylline treatment, often with no preceding signs of toxicity and in otherwise apparently normal animals.

Concurrent use of beta-sympathomimetics is contra-indicated, as additive or synergistic interactions resulting in exaggerated side effects may result.

Theophylline should be used with caution in patients with liver disease.

When theophylline is prescribed to pregnant bitches, the risk benefit of the treatment should be assessed. Only small amounts of theophylline are excreted in milk.

The following side effects have been reported; restlessness, agitation, excitement, vomiting, diarrhoea, polydipsia, sedation, reduced appetite and polyuria.

If vomiting occurs the dose should be reduced or the treatment discontinued.

If signs of CNS excitement occur (twitching, restlessness or convulsions) discontinue treatment immediately.

Plasma theophylline levels may increase in patients under treatment with macrolide and fluoroquinolone antibiotics such as erythromycin and enrofloxacin and decrease in patients receiving phenobarbitone or phenytoin.

Theophylline may reduce the convulsive threshold in patients receiving ketamine.

Administration of theophylline shortly before halothane anaesthesia may result in arrythmogenic effects.

In the case of accidental ingestion, seek medical advice immediately and show the package insert or the label to the physician.

For animal treatment only.

Keep out of reach of children.

Overdose (symptoms, emergency procedures, antidotes), if necessary

There is no specific treatment for theophylline overdose in the dog. The condition should be treated symptomatically for emetics, oral activated charcoal or anti-convulsive drugs as necessary.

Pharmaceutical precautions

Do not store above 30°C. Store in a dry place.


Dispose of used packaging in the household refuse. Unused product should be returned to the veterinary surgeon.

Legal category


Packaging Quantities

Packs containing 60 capsules are available for all 3 strengths. The capsules are packed in blister strips.

Shelf Life

Shelf life of the veterinary medicinal products as packaged for sale: 5 years.

Further information

Pharmacological Properties

Pharmacotherapeutic group: Systemic drugs for obstructive airway diseases, xanthines.

ATCvet code: QR03DA04

Pharmacodynamic Properties

Theophylline is a dimethylated xanthine which was introduced into medicine in 1900. It is similar in structure to the common dietary xanthines, caffeine and theobromine, and has many pharmacological actions. It relaxes smooth muscle, relieves bronchospasm and has a stimulant effect on respiration. Theophylline dilates coronary arteries and increases the strength of contraction of the myocardium. It also acts on the kidney to induce diuresis and is a potent stimulant of the central nervous system.

Pharmacokinetic Particulars

Absorption: The methylxanthines are readily absorbed following oral administration. Studies in man have shown that the administration of theophylline with food may slow but not reduce absorption of the drug, and help avoid local irritation of the gastro-intestinal tract. In absence of food, theophylline solutions or uncoated tablets produce maximal plasma concentration within two hours. The rate and extent of absorption of theophylline differs between various slow release formulations and absorption of the drug appears to be slower at night. However, slow release formulations, if completed absorbed, allow loner dosing intervals with less fluctuation in serum concentration.

Distribution: Theophylline is distributed into all body compartments and human studies have shown that it crosses the placenta and diffuses into breast milk. The drug also crosses the blood brain barrier and enters the central nervous system. The apparent volume of distribution of theophylline in man ranges from 300 to 700 ml/kg and in dogs 500 to 800 ml/kg. In humans, it is about 50% bound to plasma proteins, but in dogs is lower at about 9%.

Metabolism and Excretion: Little information is available concerning the metabolism and excretion of theophylline in dogs. In man, theophylline is eliminated from the body by hepatic biotransformation into relatively inactive metabolites which are excreted in the urine. Theophylline is metabolised by demethylation and oxidation, mainly to 1,3-dimethyluric acid. Dimethyluric acid and 3-methylxanthine are also formed in smaller amounts and about 10% of the drug is excreted unchanged in the urine. The half life of theophylline in adults is 8 to 9 hours, and in children it is 3.5 hours.

Marketing authorisation numbers

100 mg capsules – Vm 12501/4090

200 mg capsules – Vm 12501/4091

500 mg capsules – Vm 12501/4092

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Reviews of Corvental-D Capsules for Dogs

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Questions & Answers for Corvental-D Capsules for Dogs

Below are some recent questions we've received regarding Corvental-D Capsules for Dogs, including answers from our team.

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Corvental OD

8th Aug 2016
Sue Ferguson
  • VioVet Customer Since: August 2016
  • From: Merseyside, United Kingdom

My 41.6kg male labrador has accidentally had 2 500mg capsules today 12 hrs apart. Breakfast and supper. (Stupid humans). Will get be ok? Called vet. No reply vet. Receptionist said they would call back ...

Danielle Fletcher
  • Category Manager, Own Brand & E-SQP

Hi Sue,

Please accept my apologies for the delay in our response, I really hope that you have heard back from your vet in the meantime and your dog did not experience any side effects.

Normally, the maximum recommended dose per kg of bodyweight is 20mg. With each 500mg tablet, your dog receives approximately 12mg/kg, so if he had been given 2 x 500mg in one go he would have received 24mg/ that day, which is slightly over the recommended maximum. The fact that he received the 2 capsules 12 hours apart would have reduced the chances of exceeding this maximum dose, because his body would have already started to eliminate the drug (usually, about half of the amount is eliminated within 8-9 hours).

If this happens again I would again contact your vet for advice and watch out for the following signs and take him to the vet if you are concerned: restlessness, agitation, excitement, twitching, vomiting, diarrhoea, excessive thirst, sedation, reduced appetite and excessive volume and frequency of urination.

I hope this has been helpful.

Kind regards,


Side effects

29th Jan 2014
Carol Cunningham

My dog almost died after being prescribed corvental -D 200mg capsules for a cough. He developed a dangerously high temperature, stopped eating and appeared to be depressed and losing the will to live. After a week on the medication, luckily my husband and I rushed him back to the vet where he was given a series of antibiotics. We do believe if we had not taken our dog back to the vets when we did he would not be here today. Like us humans dogs are individuals and may react differently to prescribed drugs. Why sell such a medication which could possibly do much more harm than good and possibly be fatal, to our four legged friends who cannot complain of the side effects, and whom have to rely on, in my dogs case, his vigilant owner before it was too late for him?

John Cousins
  • Veterinary Surgeon

I am sorry to hear about your dog. I think you should talk to your vet about the possibility of the Corvental causing the problems. If this might be the case, then there is an official reporting mechanism for suspected adverse reactions to veterinary drugs. These should be reported to the Veterinary Medicine Directorate so that they can be looked into. If a drug is thought to be causing trouble, it will be withdrawn from the market. Please go to to report this very easily on the official website. If you have any trouble with this, email and we will help you. However, the truth is that Corvental is unlikely to cause a high temperature or the other symptoms you describe. A chest infection on the other hand could easily do so. The fact that you mention your vet giving antibiotics suggests that your vet thought an infection was involved. If this is the case then it is possible that the Corvental was of no benefit, but it is unlikely to have been the cause of your dog's illness. I wonder what the initial diagnosis was when your dog went onto Corvental and if this diagnosis could be questioned. Again these are matters for your vet.

On a more general note, any individual could potentially react to Corvental, especially if accidentally overdosed. This is true of all drugs. Some drugs are more likely to cause harm than others, but no drugs should ever be given if the risk outweighs the possible benefit. In your case it seems that the antibiotics helped your dog, but on another day a different dog could react badly to that same antibiotic. How then would dogs like yours be treated? We need drugs, but should use them carefully and appropriately. A correct diagnosis is also vitally important, or the drugs do not have a chance to work. Then an appropriate treatment plan has to be started. That is where the skill of your vet comes in, but withdrawing drugs too readily might cause a lot more harm than good. Please do report the matter to the VMD if you feel that would be helpful, but talk to your vet first.