Fasting Before a Cardiac Catheterization (Angiogram): What to Know

Fasting for this procedure

You're usually awake with local anesthetic and light sedation, so fasting rules are often lighter than for a general anesthetic — many cath labs ask for no solid food for about 6 hours but allow clear fluids up to about 2 hours before, and some allow a light breakfast. Staying hydrated helps protect your kidneys from the X-ray dye. Follow your cardiology unit's exact instructions, as they vary.

Medicines to check

Antiplatelets (aspirin, clopidogrel, ticagrelor) are usually continued — you may need them if a stent is placed. Don't stop them unless specifically told.

Warfarin or DOACs (Eliquis, Xarelto) — the plan varies by approach and whether a stent is likely; your cardiologist will tell you whether to pause or continue. See medications to stop.

Metformin — often paused on the day and for ~48 hours after, because the X-ray dye plus metformin can rarely strain the kidneys. Confirm with your team. See diabetes tablets.

Other diabetes medicines and insulin need adjusting around fasting — ask for a plan.

Most heart and blood-pressure medicines are continued with a sip of water — confirm each one.

When this surgery may be delayed

Fever, a new cough/cold, or any active infection

Known severe kidney problems (the dye needs extra care or hydration first)

A previous serious reaction to X-ray contrast dye that wasn't pre-treated

Very high blood pressure or uncontrolled blood sugar

You ate or drank outside the instructions you were given

Reports & documents to carry

Photo ID and your insurance or hospital paperwork

A current list of all your medicines, doses, and allergies (especially to contrast dye)

Recent blood tests, ECGs, and any previous angiogram or heart scan reports

A list of any stents or heart procedures you've had before

A ride home — you can't drive after sedation, and you'll rest first

What to ask your anesthesia team

Will it be through my wrist or groin, and might I get a stent on the same day?

Should I keep taking my aspirin and other blood thinners?

Do I stop my metformin, and for how long afterward?

Which heart and blood-pressure tablets do I take that morning?

How long will I need to lie flat or rest afterward before going home?

Your prep checklist

Tick things off as you sort them — saved on this device only, nothing is sent anywhere.

A general guide — your hospital's own instructions always come first.

Frequently asked questions

Should I stop my blood thinners before an angiogram?

Usually not the antiplatelets like aspirin or clopidogrel — you may need them if a stent is placed, so they're typically continued. Warfarin and DOACs are handled case by case. The key rule: don't stop any blood thinner on your own; follow your cardiologist's specific instruction.

Why might I need to stop metformin around the procedure?

The X-ray dye (contrast) and metformin can, rarely, combine to stress the kidneys. As a precaution many units pause metformin on the day of the procedure and for about 48 hours after, checking your kidney function before you restart. Confirm the exact plan with your team.

Will I be asleep for a cardiac catheterization?

Usually no — most are done while you're awake but relaxed, with local anesthetic at the wrist or groin and light sedation. You generally won't feel the catheter inside the blood vessels. You'll still need someone to take you home afterward because of the sedation.