Bupropion - What does it mean when it says take 1 tablet by mouth once daily for 3 days?

I’d recommend you calling your pharmacist before taking the medication.

The recommended starting dose is 200 mg per day, given as 100 mg twice daily. After 3 days of dosing, the dose may be increased to 300 mg per day, given as 100 mg 3 times daily, with at least 6 hours between successive doses. Dosing above 300 mg per day may be accomplished using the 75- or 100-mg tablets.

You can click this link for more information

https://www.drugs.com/dosage/wellbutrin.html

It sounds like either your Dr or the pharmacist made a mistake. This medication is usually taken one tablet three times a day. God bless you