Isoproterenol (trade names Medihaler-Iso and Isuprel) is a medication used for the treatment of bradycardia (slow heart rate), heart block, and rarely for asthma. Isoproterenol is a non-selective β adrenoreceptor agonist and TAAR1 agonist that is the isopropylaminomethyl analog of epinephrine. Isoprenaline's effects on the cardiovascular system (non-selective) relate to its actions on cardiac β1 receptors and β2 receptors on smooth muscle within the tunica media of arterioles. Isoprenaline has positive inotropic and chronotropic effects on the heart. β2 adrenoceptor stimulation in arteriolar smooth muscle induces vasodilation. Its inotropic and chronotropic effects elevate systolic blood pressure, while its vasodilatory effects tend to lower diastolic blood pressure. The overall effect is to decrease mean arterial pressure due to the β2 receptors' vasodilation. The adverse effects of isoprenaline are also related to the drug's cardiovascular effects. Isoprenaline can produce tachycardia (an elevated heart rate), which predisposes patients to cardiac arrhythmias.

Metiprenaline was developed as a bronchodilator. Information about the current use of this compound is not available.

Proline (L-Proline) is one of the twenty amino acids used in living organisms as the building blocks of proteins. Proline is a non-essential amino acid that is synthesized from glutamic acid. It is an essential component of collagen and is important for proper functioning of joints and tendons. Proline is used in pharmaceuticals as an excipient and as an active substance in nutritional supplements. Proline is not commonly used in pharmaceuticals as an excipient. It is approved for use in Privigen (IVIg) and Hizentra (SCIg) solution for injection as a stabiliser for IgG. Proline is also contained in low amounts in several vaccines, e.g. Havrix 720 Kinder (Hepatitis A).