means as needed
tid prn means three times daily as directed
The term 'prescription' has several senses or meanings: 1: a drug that is available only with written instructions from a doctor or dentist to a pharmacist; 2: available only with a doctor's written...
"Tid" means take 3 times daily, "prn" means as needed. So tid prn means "Take three times daily as needed."
"As needed"
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