Theophylline is an alkaloid of the methylxanthine family, which is used for the treatment of different respiratory pathologies in dogs due to its bronchodilator effect. Despite being an effective drug, it produces highly variable responses in patients, which makes it necessary to individualize the dose in each animal and to monitor the plasma levels of the drug. In addition, during treatment, the appearance of adverse reactions that may require dose adjustment or discontinuation of treatment should be monitored.
If you want to know more about theophylline for dogs, its dosage, uses and side effects join us in this article on our site at which we also explain what its contraindications are.
What is theophylline?
Theophylline is an alkaloid belonging to the methylxanthine family that is often used in veterinary medicine for the treatment of various respiratory pathologies.
Caffeine is a widely known compound that also belongs to the methylxanthine family. Therefore, we can intuitively deduce that we are dealing with a family of central nervous system stimulant drugs Methylxanthines are drugs that act on the purinergic system, the which is associated with the central and peripheral nervous system. Specifically, they act blocking the purinergic system, which produces a stimulating effect on the nervous system.
Don't hesitate to consult this other article on respiratory diseases in dogs.
What is theophylline for dogs for?
Theophylline is a drug that produces effects in multiple organic territories. Among other things, stimulates the nervous system, has diuretic action,vasodilator effect or vasoconstrictor and inotropic effect at cardiac level
However, in dogs it is used to treat diseases that affect the respiratory system due to its bronchial action, given that:
- Produces bronchodilation: by relaxation of the bronchial muscles.
- Inhibits the release of bronchoconstrictor mediators.
- Increases mucociliary clearance.
- Prevents diaphragmatic fatigue.
- In addition, it allows you to reduce the dose of corticosteroids.
Specifically, theophylline is used in dogs for the treatment of tracheobronchial diseases such as tracheal collapse, chronic bronchitis or Chronic obstructive pulmonary disease.
It should be noted that, although theophylline is a drug used to treat certain respiratory diseases in dogs, it is not currently marketed in Spainno veterinary drug containing theophylline for use in small animals.
Therefore, when your veterinarian decides to start treatment with this drug, you should use the cascade prescription: which consists in the prescription of a drug that is not authorized for a specific animal species when there is a therapeutic gap. Oral or parenteral formulations that are marketed for use in people are generally prescribed.
Don't hesitate to read these other articles on our site about Tracheal Collapse in Dogs, Symptoms and Treatment and Bronchitis in Dogs, Symptoms and Treatment.
Theophylline Dosage for Dogs
One of the reasons why theophylline is not usually used as a treatment of first choice is the enormous variation in the response of patients, which makes it necessary to individualize the dose in each animal and to monitor the plasma levels of the drug.
As a guide, effective doses are considered in dogs:
- Orally: 10 mg per kg of weight every 12 hours (although they can vary between 7, 5-30 mg per kg weight every 12 hours
- Intravenous or intramuscular route: 4-8 mg per kg of weight.
However, once treatment has been started, it is important to monitor the plasma levels of the drug in order to adapt the dose to each patient based on the effect and the appearance of adverse reactions.
Theophylline Overdose in Dogs
Theophylline overdoses in dogs can occur as a result of dosing errors of the drug oraccidental massive ingestion , which is the most frequent cause.
Theophylline overdose will result in various adverse reactions including:
- Vomiting. If you want to know more about Vomiting in dogs: its causes and treatment, read this article that we recommend.
- Tachycardia. Check out this post from our site about 5 symptoms of heart disease in dogs, here.
- Tremors. Why is my dog trembling and can't walk? Find out the answer in the following article.
- Excitement.
- Seizures. You can also take a look at this article on our site about Seizures in dogs: their causes, treatment and what to do.
Therefore, as soon as theophylline poisoning is detected, you should go to an emergency room to a veterinary center to avoid absorption of the drug as far as possible (by inducing vomiting, performing gastric lavage, or administering activated charcoal or laxatives) and to treat signs associated with intoxication.
In any case, remember the importance of keeping any medicinal product away from your pets, as it will be the most effective way to avoid poisoning by accidental ingestion.
Theophylline Side Effects in Dogs
Despite being a drug with multiple beneficial effects, theophylline can also induce various side effects, especially when administered at high doses. The main adverse reactions associated with the use of theophylline are:
- Generalized stimulation of the central nervous system: at very high doses it can cause nervousness, tremor, hyperesthesia, muscle contractions, hyperexcitability and including tonic-clonic seizures. Perhaps this article about Cramps in dogs: their causes, symptoms and what to do may interest you.
- Digestive signs: vomiting (since it stimulates the vomiting center) and diarrhoea. Do not hesitate to take a look at this article on the Types of diarrhea in dogs.
- Cardiac disorders: sinus or ventricular tachycardia, extrasystoles or ventricular arrhythmia.
- Vascular disorders: vasodilation and hypotension.
When any of these adverse reactions appear, the plasma concentration of theophylline should be analyzed to adjust the dose. In severe cases, drug administration should be discontinued.
Contraindications of theophylline for dogs
Before initiating theophylline therapy in dogs, it is important to consider the situations in which the administration of this drug is contraindicated:
- Allergy or hypersensitivity to the active ingredient to other methylxanthines.
- Allergy or intolerance to the excipients of the drug: sucrose, lactose, starch, etc.
- Acute tachyarrhythmia.
- Breastfeeding: since theophylline is excreted in breast milk.
- Treatments with: enrofloxacin, clindamycin, cimetidine, allopurinol, lincomycin and/or β-blockers, since theophylline produces drug interactions with these drugs. Patients who require combined treatments with theophylline and any of these drugs should be monitored to avoid a possible overdose.
