Take every 12 hours. See link: http://www.medterms.com/script/main/art.asp?articlekey=5033
Looks like a typo. Best plan would be to call the prescriber.
every 4 weeks
every 4 hours
every 4 hours.
It means to take the medication three times a day.
"Every 6 hours, PRN"
Methadone you mean? Yes it does show up in a drug test.
SID dosing is the veterinary term for "once daily dosing." Equivalent to qd in human medicine.
Is it "prd" or "PRN"? PRN means "as needed".
'PO' or 'p.o.' means 'Per Oral'; that is, take the prescribed drug dose by mouth