Blessing is related to Ok. Ok is the opposite of Poor. Poor is related to Trailer. Trailer is related to Motor. 
Prescription is related to Drug. Drug is related to Trip. 
Blessing <--RelatedTo--> Ok <--Antonym--> Poor <--RelatedTo--> Trailer <--RelatedTo--> Motor 
Prescription <--RelatedTo--> Drug <--RelatedTo--> Trip 