Generic Drug Name: Terbutaline
Other Common Names: Brethine
Terbutaline is a beta2 agonist that acts as an airway dilator to improve breathing in cases of asthma, tracheal collapse, bronchitis, and other respiratory problems. It works by stimulating beta2 receptors to cause smooth muscles to relax, which in turn causes airways to open. The drug can also be used to increase heart rate in animals suffering from a slow heart rate and to slow down or stop uterine contractions.
Terbutaline is used in both dogs and cats. It is not approved by the Food and Drug Administration for use in animals, but it is prescribed legally as an extra-label drug by veterinarians.
Terbutaline is known to cause side effects when taken at the proper dose. Some of these include dizziness, increased heart rate, tremors, and excitement. These effects are typically mild and pass quickly.
Terbutaline should not be used in animals suffering from diabetes mellitus, as it may cause increases in blood sugar. It should be used with caution in animals with hypertension, hyperthyroidism, low potassium levels, or hypertrophic cardiomyopathy. Animals with seizure disorders may experience an increase in seizures while undergoing treatment with terbutaline. Animals experiencing significant respiratory distress should not rely on terbutaline, as the drug takes 15 minutes to several hours to take effect. Emergency help should be sought instead.
Terbutaline interacts with a variety of medications and supplements, so it is important to disclose all medical history before beginning treatment with this drug. Medications that stimulate the sympathetic nervous system can cause heart arrhythmias when used along with terbutaline. Other drugs known to interact with terbutaline include beta blockers, digitalis, MAO inhibitors, tricyclic antidepressants, and others.
Terbutaline should not be used in animals with a known allergy or hypersensitivity to the drug. Overdose of terbutaline is potentially serious and may cause dilated pupils, high blood pressure, fever, vomiting, and heart rhythm disturbances. Any known or suspected overdose should be reported to a veterinarian right away.
Terbutaline should be stored in its original packaging, at room temperature, and away from children and animals. It should not be exposed to light or heat.
Terbutaline is available as an injectable, as a metered-dose inhaler, and as tablets in strengths of 2.5 mg and 5 mg. In both dogs and cats, the typical dose of terbutaline as an injectable is 0.005 mg/lb (0.01 mg/kg) every 4 to 6 hours. In tablet form for dogs, the typical dose is 1.25 to 5 mg per dog every 8 hours. In tablet form for cats, the dose is 0.05 to 0.1 mg/lb (0.1 to 0.2 mg/kg) every 12 hours.
Doses may vary in different species, when the drug is given by a different route or concurrently with other medications, and with regards to a patient's age, breed, and health status. A veterinarian's dosing instructions and/or those printed on the medication label should be followed closely.
If a dose of terbutaline is missed, it should be given as soon as possible. If it is almost time for the next dose, the missed dose should be skipped. Two doses of this medication should not be given at once.