Are there any foods I should avoid while taking carvedilol?

No specific food contraindications or interactions have been noted for carvedilol.^1-5  Carvedilol should always be taken with food.

Grapefruit juice, however, should be consumed with caution when taking certain medications,⁶ as its interactions with cardiovascular drugs, such as beta blockers, can alter the pharmacokinetics and pharmacodynamics of the drugs.⁷ Grapefruit juice, a CYP3A4 and CYP1A2 inhibitor,⁸ can increase the bioavailability of carvedilol⁹ and may enhance drug toxicity.¹⁰ A manufacturer of carvedilol reports that drinking 300 mL of grapefruit juice can increase plasma carvedilol concentration⁸ by 16%.

^References

1. Frishman WH. Carvedilol. N Engl J Med. 1998;339(24):1759-1765.
2. Morgan T. Clinical pharmacokinetics and pharmacodynamics of carvedilol. Clin Pharmacokinet. 1994;26(5):335-346. 1994.
3. Coreg [package insert]. Ciales, PR: GK Pharmaceuticals Contract Manufacturing Operations; 2008.
4. Coreg CR [package insert]. Ciales, PR: GK Pharmaceuticals Contract Manufacturing Operations; 2008.
5. Tenero DM, Henderson LS, Baidoo CA, et al. Pharmacokinetic properties of a new controlled-release formulation of carvedilol. Am J Cardiol. 2006;98(7, Supplement 1):5-16.
6. U.S. Department of Health and Human Services. Grapefruit juice and some drugs don't mix. U.S. Food & Drug Administration. https://www.fda.gov/ForConsumers/ConsumerUpdates/ucm292276.htm. Accessed October 19, 2018.
7. Lim GE, Li T, Buttar HS. Interactions of grapefruit juice and cardiovascular medications: A potential risk of toxicity. Experimental and clinical cardiology. 2003;8(2):99-107.
8. APO-Carvedilol [package insert]. Toronto, Canada: Apotex Pharmaceutical Holdings Inc.; 2015.
9. Dresser GK, Bailey DG. The effects of fruit juices on drug disposition: a new model for drug interactions. Eur J Clin Invest. 2003;33(s2):10-16.
10. Bailey DDG, Dresser GK. Interactions between grapefruit juice and cardiovascular drugs. Am J Cardiovasc Drugs. 2004;4(5):281-297.