Rapastinel Dosing Calculator

Dose

1-3 mg

Frequency

1-2 times weekly

Duration

4-6 weeks

Route

Intranasal

Some users attempt intranasal delivery for brain penetration; no data supports this route for rapastinel

Dose

Single IV dose of 1, 5, 10, or 30 mg/kg. The 5 and 10 mg/kg doses demonstrated significant antidepressant effects.

Frequency

Single dose (phase 2); weekly IV infusion explored in phase 3

Duration

Single dose in phase 2; repeated weekly dosing in phase 3

Clinical development was discontinued after phase 3 failure in March 2019. These doses are from clinical trial protocols and are not approved for therapeutic use.

How much bacteriostatic water should I add to a 5 mg vial of Rapastinel?

The community standard is 2 mL of bacteriostatic water for a 5 mg Rapastinel vial. That gives a concentration of 2.50 mg/mL, so a 1 mg dose is 40 units on a U-100 insulin syringe. Adding 1 mL instead doubles the concentration to 5.00 mg/mL and halves the draw to 20 units. Less water = smaller injection volume but harder to measure precisely.

How many syringe units is a 1 mg dose of Rapastinel?

On a standard U-100 insulin syringe, a 1 mg dose of Rapastinel is 40 units when the 5 mg vial is reconstituted with 2 mL of bacteriostatic water (2.50 mg/mL). If you use 1 mL of bac water instead, draw 20 units (5.00 mg/mL).

What is the standard Rapastinel dose?

Community-reported protocols for Rapastinel typically use 1 mg–5 mg once weekly via Subcutaneous. 1 mg is a common starting dose. Adapted from clinical IV dosing; community uses SubQ as a practical alternative to IV infusion

How long does a vial of Rapastinel last at 1 mg once weekly?

A 5 mg vial of Rapastinel contains roughly 5 doses at 1 mg per injection. At once weekly dosing, that is approximately 35 days (about 5 weeks) of supply per vial. Reconstituted Rapastinel should generally be used within 28 days when refrigerated.

Where do you inject Rapastinel?

Rapastinel is typically injected subcutaneous. Common sites reported in the literature and by users include: Intravenous infusion (clinical trial setting only). Rotate sites with each injection to reduce localized irritation.

Can I use sterile water instead of bacteriostatic water for Rapastinel?

Bacteriostatic water (containing 0.9% benzyl alcohol as a preservative) is strongly preferred for multi-dose vials like Rapastinel because it inhibits microbial growth and lets a single vial be used over multiple weeks. Sterile water has no preservative and should generally be reserved for single-use preparations only.