Final answer:
Isoprenaline acts on beta receptors, similar to adrenaline, and can increase heart rate and blood pressure. It is not extensively used for treating ischemic heart disease or as a substitute for metaraminol in treating hypotension. Isoprenaline usually decreases systemic vascular resistance and increases heart rate.
Step-by-step explanation:
The student asked whether isoprenaline can be used as a substitute for metaraminol for the treatment of hypotension, its use in treating ischemic heart disease, and its effects on systemic vascular resistance (SVR) and heart rate. Isoprenaline is a sympathomimetic drug that primarily acts on beta receptors, similar to adrenaline, which has a stimulatory effect on heart rate and blood pressure. In contrast, ß-blockers are antagonistic to adrenaline and can inhibit these effects.
Isoprenaline could theoretically be used as a substitute for metaraminol, as both are vasopressors, but they work through different mechanisms and isoprenaline is not commonly used for this indication. Isoprenaline is also not extensively used to treat ischemic heart disease because it can increase heart work and might exacerbate ischemia. Furthermore, isoprenaline typically causes a decrease in SVR and an increase in heart rate (opposite of bradycardia).