<P> Although minor compared to those of epinephrine, beta agonists usually have mild to moderate adverse effects, which include anxiety, hypertension, increased heart rate, and insomnia . Other side effects include headaches and essential tremor . Hypoglycemia was also reported due to increased secretion of insulin in the body from activation of β receptors . </P> <P> In 2013, zilpaterol, a β agonist sold by Merck, was temporarily withdrawn due to signs of sickness in some cattle that were fed the drug . </P> <P> Most agonists of the beta receptors are selective for one or more beta - adrenoreceptors . For example, patients with low heart rate are given beta agonist treatments that are more "cardio - selective" such as dobutamine, which increases the force of contraction of the heart muscle . Patients who are suffering from a chronic inflammatory lung diseases such as asthma or COPD are treated with salbutamol (albuterol), which mainly induces smooth muscle relaxation in the lungs and less contraction of the heart . </P> <P> β agonists are currently in clinical research and are thought to increase the breakdown of lipids in obese patients . </P>

Which of the following types of drugs would be a strong agonist