Does Grapefruit Affect Monacolin K?

Use extra care with this combination

The short answer

Monacolin K is identical to lovastatin, a CYP3A4 substrate. Grapefruit can increase its blood levels 5-15x, risking severe myopathy and rhabdomyolysis.

How to arrange timing

Do not consume grapefruit while taking monacolin K. This is a well-established dangerous interaction.

Reference

Reference noted for this food and supplement combination: FDA; Kantola et al., Clin Pharmacol Ther 1998

Important context

The effect can also change with food amount, supplement dose, product formulation, health conditions, and medication use. Ask a doctor or pharmacist first if you take medication, are pregnant or breastfeeding, or have a chronic condition.