What is the appropriate timing interval between dolutegravir (Tivicay) dosing and enteral nutrition feeds containing multivalent cations?

Temporal Spacing for Tivicay and Enteral Nutrition

Administer Tivicay (dolutegravir) 2 hours before or 6 hours after enteral nutrition feeds that contain polyvalent cations (magnesium, aluminum, calcium, iron). 1

Key Administration Guidelines

The FDA labeling for Tivicay explicitly addresses this interaction with medications and supplements containing polyvalent cations:

• Standard spacing: Give dolutegravir 2 hours before OR 6 hours after enteral feeds containing cations 1
• Exception with food: When dolutegravir is taken WITH food, calcium or iron supplements can be administered simultaneously 1
• Fasting conditions: Strict 2-hour before or 6-hour after spacing must be maintained 1

Mechanism and Clinical Rationale

Polyvalent cations (Mg²⁺, Al³⁺, Ca²⁺, Fe²⁺/³⁺) commonly found in enteral nutrition formulations chelate with dolutegravir, significantly reducing its absorption and plasma concentrations 1. This interaction can lead to subtherapeutic drug levels and potential treatment failure.

Special Considerations for Critically Ill Patients

Important caveat: Real-world data from ICU patients suggests that even with appropriate temporal spacing, dolutegravir concentrations may still be suboptimal in critically ill patients receiving enteral nutrition 2. In a case series of 6 ICU patients:

• Most dolutegravir trough concentrations fell below the typical therapeutic range (830-1110 ng/mL)
• 6 of 8 measurements were below the minimum effective concentration of 300 ng/mL
• However, most remained above the protein-adjusted IC90 for wild-type virus (64 ng/mL) 2

Additional factors affecting absorption in critical illness:

• Delayed gastric emptying
• Altered gastric pH
• Reduced splanchnic blood flow
• Variable drug metabolism 2

Practical Implementation Algorithm

1. If patient can tolerate interrupted feeds:

   • Hold enteral nutrition
   • Give dolutegravir
   • Resume feeds 2 hours later

2. If continuous feeds are medically necessary:

   • Hold feeds for 2 hours before dolutegravir dose
   • Administer dolutegravir
   • Resume feeds 2 hours after administration (total 4-hour interruption)

3. Monitor closely:

   • Check HIV viral load at 1 month, then every 3 months 3
   • Consider therapeutic drug monitoring if available, especially in critically ill patients 2
   • Ensure viral load remains suppressed (<50 copies/mL)

Critical Pitfalls to Avoid

• Do not assume therapeutic concentrations are achieved even with proper spacing in ICU patients—viral load monitoring is essential 2
• Do not co-administer with enteral feeds under fasting conditions, as this dramatically reduces absorption 1
• Do not use the "with food" exception for enteral feeds—this only applies to oral calcium/iron supplements taken with regular meals 1
• Avoid crushing tablets when possible, though case reports demonstrate absorption can occur via enteral route with 2-hour separation from feeds 4