Certified Hospice and Palliative Assistant (CHPNA) Practice Test

How does subcutaneous morphine compare to intravenous injections in terms of onset of effects?

1. It has an immediate peak effect

2. It has a quicker onset

3. It has a delayed peak effect

4. It is ineffective

The correct answer is: It has a delayed peak effect

Subcutaneous morphine administration is characterized by a delayed peak effect compared to intravenous injections. This delayed peak occurs because subcutaneous morphine must first diffuse through the subcutaneous tissue and then enter the bloodstream, which takes more time than the direct injection of morphine into the bloodstream through an intravenous route. In contrast, intravenous injections deliver the medication directly into the venous circulation, leading to a more rapid increase in blood concentration and a quicker onset of effects. While subcutaneous morphine is effective and useful, especially in palliative settings where intravenous access might be challenging, the physiological differences in absorption result in a more gradual onset of effects than what is seen with intravenous administration. It is important to understand this distinction in the context of palliative care, where timing and management of pain relief are crucial. In scenarios where rapid pain control is necessary, intravenous morphine might be preferred due to its quicker onset, whereas the subcutaneous route may be more appropriate for longer-term management where gradual symptom control is acceptable.