Final answer:
Misoprostol is a cytoprotective drug that acts as a PGE1 analog to replace the gastro-protective prostaglandins removed by NSAIDs.
Step-by-step explanation:
The cytoprotective drug that is a PGE1 analog and replaces the gastro-protective PGs removed by NSAIDs is Misoprostol.
Misoprostol is a synthetic analog of prostaglandin E1 (PGE1) and is commonly used to prevent and treat gastric ulcers caused by NSAIDs. It helps protect the stomach lining by increasing the production of mucus and bicarbonate, which form a protective layer and reduce the damage caused by NSAIDs. For example, when NSAIDs inhibit the production of prostaglandins, including the gastro-protective prostaglandins, misoprostol can be used to replace them and provide cytoprotective effects.