Theophylline for Dogs - Dosage, Uses and Side Effects
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Theophylline is an alkaloid of the methylxanthine family and is used to treat various respiratory diseases in dogs due to its bronchodilator effect. Although it is an effective drug, it causes widely varying reactions in patients, so the dose must be individualized in each animal and plasma levels of the drug monitored. In addition, it is important to monitor the occurrence of side effects during treatment, which may require dose adjustment or even discontinuation of treatment.
The following AnimalWised article explains everything you need to know about theophylline for dogs, its dosage, use, side effects and contraindications.
What is theophylline?
Theophylline is an alkaloid that belongs to the methylxanthine family and is commonly used in veterinary medicine to treat various respiratory diseases.
Caffeine is a widely known compound that also belongs to the methylxanthine family. From this we can see that we are dealing with a family of drugs that stimulate the central nervous system. Methylxanthines are drugs that act on the purinergic system, which is associated with the central and peripheral nervous systems. More specifically, they block the purinergic system, which has a stimulatory effect on the nervous system. Methylxanthines are effective in treating respiratory problems because they relax the muscles around the airways, so they open up, and you can breathe easier. They also reduce the lungs' response to irritants.
Respiratory problems in dogs may be due to mild respiratory disease, but may also reflect cardiac problems, especially in older dogs. Continue reading this article to learn more about the most common causes of respiratory distress in dogs.
What is theophylline used for in dogs?
Theophylline is a drug that exerts effects in several organic areas. Among other things, it stimulates the nervous system, has a diuretic effect, a vasodilator or vasoconstrictor effect, and an inotropic effect on the heart. However, in dogs it is used to treat respiratory diseases due to its bronchial action, in the following ways.
- Produces bronchodilation by relaxing bronchial muscles.
- Inhibits the release of bronchodilator neurotransmitters.
- Increases mucociliary clearance.
- Prevents fatigue of the diaphragm.
- Reduces the dose of corticosteroids.
Specifically in dogs, theophylline is also used to treat tracheobronchial disorders such as tracheal collapse, chronic bronchitis, or chronic obstructive pulmonary disease.
Difficult breathing (dyspnea) is a clinical symptom that should be of concern to every dog owner. The onset of labored and forced breathing can be quite sudden, or it can be the result of a progressive deterioration. If you notice that your dog is having difficulty breathing through his nose, continue reading this other article, where we explain why your dog is having trouble to breathe.
Dosage of theophylline in dogs
One of the reasons why theophylline is not usually used as first-line therapy is the tremendous variability in patient response, which requires individualized dose adjustment in each animal and monitoring of plasma levels of the drug.
As a guide, the following dosages are considered effective in dogs:
- Oral administration: 10 mg per kg body weight every 12 hours (although doses may vary from 7.5-30 mg per kg body weight every 12 hours).
- Intravenous or intramuscular administration: 4-8 mg per kg body weight.
However, once treatment is started, it is important to monitor the plasma levels of the drug to adjust the dose for each patient according to the effect and the occurrence of side effects.
Theophylline overdose in dogs
Theophylline overdoses in dogs can result from errors in dosing the drug or accidental massive ingestion, which is the most common cause.
An overdose of theophylline leads to the occurrence of several adverse effects, including:
If theophylline poisoning is detected in a pet, the animal should be taken to a veterinarian as soon as possible to prevent further poisoning by the drug. The veterinarian could induce vomiting, perform a gastric lavage, or administrate activated charcoal or laxatives.
In any case, remember that it is critical to keep all medications away from your pets, as this is the most effective way to prevent poisoning from accidental ingestion.
If you ever find yourself in a situation where you suspect your dog may be poisoned, continue reading this other article on dog poisoning to learn what to do.
Side effects of theophylline in dogs
Although theophylline is a drug with numerous beneficial effects, it can also cause various side effects, especially when administered in high doses. The main side effects associated with taking theophylline are:
- General central nervous system stimulation: in very high doses, it can cause nervousness, tremors, hyperesthesia, muscle contractions, hyperexcitability, and even tonic-clonic seizures.
- Digestive signs: Vomiting and diarrhea.
- Cardiac disorders: Sinus or ventricular tachycardia, extrasystoles, or ventricular arrhythmia.
- Vascular disorders: Vasodilation and hypotension.
If any of these adverse effects occur, the plasma concentration of theophylline should be analyzed to adjust the dose. In severe cases, use of the drug should be discontinued.
Vomiting and diarrhea are relatively common in dogs and can sometimes worry their owners. This situation can become increasingly worrisome if it does not stop or if blood appears in the vomit or feces. Continue reading in this other article where we explore all the possible causes of vomiting and diarrhea in dogs.
Contraindications to theophylline in dogs
Before initiating theophylline treatment in dogs, consider the situations in which administration of this drug is contraindicated:
- Allergy or hypersensitivity to the active ingredient or other methylxanthines.
- Allergy or intolerance to the excipients of the medication: sucrose, lactose, starch, etc.
- Acute tachyarrhythmia.
- Lactation, as theophylline is excreted into breast milk.
- Treatments that include Enrofloxacin, clindamycin, cimetidine, allopurinol, lincomycin and/or β-blockers, as theophylline interacts with these drugs. Patients requiring combined treatment with theophylline and any of these drugs should be monitored to avoid possible overdose.
If you want to learn more about tachyarrhythmia and other forms of heart failure in dogs, read this other article where we explain the most common symptoms of heart failure in dogs.
This article is purely informative. AnimalWised does not have the authority to prescribe any veterinary treatment or create a diagnosis. We invite you to take your pet to the veterinarian if they are suffering from any condition or pain.
If you want to read similar articles to Theophylline for Dogs - Dosage, Uses and Side Effects, we recommend you visit our Medicine category.
- Spanish Agency for Medicines and Health Products. Technical Sheet Elixifilin 5.33mg/ml Oral Solution . Available at: https://cima.aemps.es/cima/dochtml/ft/45303/FT_45303.html
- Botana, L.M. (2016). Veterinary pharmacology: fundamentals and therapeutic applications . Pan American Medical Publishing House.