Along with its needed effects, terbutaline may cause some unwanted or undesirable effects. Generally, terbutaline is well tolerated and many people will not experience unwanted effects. The severity and duration of these effects are dependant on many factors including duration of therapy, dose, route of administration and individual response. Possible unwanted effects include:

• nervousness
• slight palpitations (awareness of heart beat)
• tremor
• restlessness
• headache

Uncommon:

• increased heart rate
• dizziness
• nausea
• muscle cramps
• trouble sleeping
• weakness
• flushing

Rare:

• restlessness
• irritability
• unusual taste
• angina (chest discomfort)

Many of these unwanted effects, especially the most common ones, may disappear with continued use. Check with the doctor or pharmacist if any of them continue or become bothersome.

Terbutaline is a short-acting bronchodilator that acts at specific receptors called beta2- adrenergic receptors. Stimulating these beta receptors in the bronchial smooth muscle causes the muscle to relax, allowing the bronchial tubes to dilate (widen). This bronchodilation relieves spasm or contraction of the muscle, allowing air to move in and out of the lungs more freely.

Use exactly as prescribed. Never exceed the maximum dosage set by your physician. If you find that you are not responding to your usual dose, it could mean that your asthma is worsening and you should contact your physician. Increasing the dose, especially over extended periods, can lead to tolerance. Keep in mind that the bronchodilator action should last between 4 to 7 hours. If you are using terbutaline for an acute asthma episode and the condition continues or worsens, stop using the terbutaline and call your doctor. If you need to use terbutaline to relieve symptoms more than 3 times a week you should also be using an anti-inflammatory medication (e.g. budesonide, fluticasone).
Drug Interactions: Be sure to tell your doctor and pharmacist about any prescription or over-the-counter medications you are taking. The following drugs and drug classes have been known to interact with terbutaline:

• MAO (monoamine oxidase) inhibitors (e.g. phenelzine, tranylcypromine)
• tricyclic antidepressants (e.g. amitriptyline)
• some beta-blockers (e.g. propranolol)
• other bronchodilators (e.g. salbutamol)

Use is not recommended in the following situations:

• allergy to terbutaline or any component of the preparation
• cardiac arrhythmia (irregular heart beat) associated with tachycardia (rapid heart rate)

Caution is recommended in the following situations:

• hyperthyroidism (overactive thyroid)
• high blood pressure
• diabetes
• history of seizures
• heart disease
• sensitivity to sympathomimetics (drugs that stimulate the central nervous system)

Use in pregnancy: Generally considered safe to use in pregnancy but contact your doctor or pharmacist before using.
Use while breastfeeding: Considered safe to use if breastfeeding.