Analgesics

	Morphine	Fentanyl	Hydromorphone
Onset (min)	5-10	1-2	5-10
Duration (h)	2-4	1-5	2-6
Prolonged in renal	yes	no	no
Prolonged in hepatic	yes	yes	yes
T 1/2 in hours	1-4	2-5	2-3
Active metabolites	yes	no	no
Hypotension	yes	no	yes
Flushing	yes	no	yes
Bronchospasm	yes	no	no
Constipation	yes	yes	yes

For allergies and drug testing, I like to remember that codeine is metabolized to morphine, hydrocodone to hydromorphone, and oxycodone to oxymorphone. [it’s a little more complex than that in reality, but these are good to remember].

The presence of morphine in urine can indicate exposure to morphine, heroin, or codeine within 2 to 3 days. Ingestion of bakery products containing poppy seeds can also cause morphine to be excreted in the urine.  The presence of hydromorphone greater than 100 ng/mL indicates exposure within 2 to 3 days prior to specimen collection, but could also indicate exposure to hydrocodone. The presence of oxycodone greater than 100 ng/mL indicates exposure to oxycodone within 2 to 3 days prior to specimen collection.