Side Effects of Brethine

Brethine is a brand name for the medication terbutaline, a bronchodilator prescribed to treat asthma and other lung disorders. A beta adrenergic receptor agonist, Brethine expands air passages in the lungs so the person can breathe more easily. Several side effects are possible.

Most Common Effect

In clinical studies with Brethine, as detailed by eMedTV, the most common side effect was nervousness, experienced by up to 35 percent of participants in some studies.

Other Side Effects

Other side effects experienced between 5 to 15 percent of participants include drowsiness, headaches and shakiness or tremors. Less common side effects included dizziness, dry mouth, flushing or hot flashes, increased perspiration, insomnia, nausea and weakness.


People with certain conditions may not be able to use Brethine. The medication can worsen symptoms of diabetes, epilepsy and hyperthyroidism. Brethine can cause low blood potassium and high blood sugar.

Cardiovascular Issues

Brethine can have a stimulating effect on the heart and blood pressure, resulting in a fast or irregular heart rate, heart palpitations or high blood pressure.

Allergic Reaction

Rarely, some people have an allergic reaction to Brethine. Signs are rash or hives, itching, swelling, difficulty swallowing, wheezing and difficulty breathing.

Brethine is a brand name for the medication terbutaline