Infection & antiviral

Daptomycin

Also called Cubicin, Cubicin RF, LY146032

Daptomycin is an antibiotic made by soil bacteria. It is a ring-shaped peptide with a fatty tail that punches holes in the outer membrane of Gram-positive bacteria such as MRSA, and it is given by IV for serious skin and bloodstream infections.

FDA-approvedApproved by the FDA for at least one use after large human trials.

All printable flashcards

Drawn from its published sequence: 13 residues, one bead each. Dashed arcs are ring bonds. The gold tail marks the fatty-acid chain.

Overview

How it works

Established: with calcium, daptomycin inserts into the bacterial cell membrane where phosphatidylglycerol is present and clusters there. This bends the membrane and lets ions leak out, quickly collapsing the membrane's charge. The cell can no longer make DNA, RNA or protein and dies. It works only on Gram-positive bacteria. It sticks to lung surfactant, which is why it does not work for pneumonia.

What research shows

Randomized open-label trial in S. aureus bacteremia and endocarditis (Fowler et al., NEJM 2006): daptomycin 6 mg/kg/day was non-inferior to standard therapy.
Approved for complicated skin infections and S. aureus bacteremia (including right-sided endocarditis) in adults and children 1-17 (FDA label).

Doses studied in people

Study or label	Dose used	Source
FDA label, complicated skin and skin-structure infections (adults)	4 mg/kg IV once every 24 hours for 7-14 days	¹
FDA label, S. aureus bacteremia (adults)	6 mg/kg IV once every 24 hours for 2-6 weeks; every 48 hours if CrCl <30 mL/min	¹
FDA label, pediatric (1-17 years)	Age-based 5-12 mg/kg IV once daily depending on infection type	¹

Hospital or infusion-center IV antibiotic; dosed by weight, age and kidney function per the label.

Read this first: these are the amounts given to participants in published studies or written on official prescribing labels, reported for reference. They are not recommendations. Trial doses were chosen for specific patients under medical supervision, and a dose that is safe in one person can be harmful in another.

Safety

Muscle damage (myopathy, rhabdomyolysis): check CPK weekly; stop for unexplained muscle symptoms with CPK >1,000 U/L or CPK >2,000 U/L without symptoms (FDA label).
Eosinophilic pneumonia, DRESS, tubulointerstitial nephritis and peripheral neuropathy (FDA label).
C. difficile-associated diarrhea; anaphylaxis (FDA label).
Not for pneumonia (inactivated by lung surfactant) or left-sided endocarditis (FDA label).
Avoid under 12 months of age (muscle and nerve effects in neonatal dogs) (FDA label).

Report side effects of any drug or product to the FDA through MedWatch. For a possible poisoning in the US, call Poison Control at 1-800-222-1222.

Legal status

FDA: FDA-approved (Cubicin, 2003; generics available) for complicated skin infections and S. aureus bacteremia.
Compounding: FDA-approved drug; not a 503A bulk compounding substance.
Sports (WADA): Not named on the 2026 WADA Prohibited List (antibiotic).
Other: Prescription only.

Rules change often. See Legal status of peptides for how these categories work.

Storage and stability

Per product: original Cubicin vials refrigerated; Cubicin RF can be stored at room temperature (FDA label/Wikipedia).

General lab handling, not instructions for personal use. See Storage and stability.

History

Eli Lilly discovered daptomycin (LY146032) in the 1980s but stopped development over muscle side effects at high doses. Cubist Pharmaceuticals licensed it in 1997, found that once-daily dosing reduced muscle toxicity, and won FDA approval as Cubicin in September 2003. A room-temperature formulation (Cubicin RF) was approved in 2016.

Common questions

Is daptomycin FDA-approved?

Yes. It was approved as Cubicin in 2003, and generics are available, for complicated skin infections and Staphylococcus aureus bloodstream infections ¹. It is prescription only ¹.

How does daptomycin kill bacteria?

With calcium, it inserts into the bacterial cell membrane, bends it and lets charged particles leak out ⁴. The cell can no longer make DNA, RNA or protein and dies, and this only works on Gram-positive bacteria ⁴.

Why isn't daptomycin used for pneumonia?

It sticks to lung surfactant, the slippery coating inside the lungs, which switches it off ¹⁴. The label also says it is not for left-sided heart valve infections ¹.

What does the research show?

A 2006 randomized trial in S. aureus bloodstream and heart valve infections found daptomycin was not worse than standard treatment ³. It is approved for adults and for children aged 1 to 17 ¹.

What doses are on the FDA label?

The label lists 4 mg/kg IV once daily for 7 to 14 days for skin infections and 6 mg/kg IV once daily for 2 to 6 weeks for S. aureus bloodstream infection in adults ¹. Children get age-based doses, and doses are adjusted for kidney function by the care team ¹.

What are the main risks?

Muscle damage is a key risk, so the label calls for weekly blood tests of the muscle enzyme CPK ¹. It can also cause a type of lung inflammation, serious skin and kidney reactions, nerve damage and C. difficile diarrhea ¹.

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Sources

Last reviewed 2026-10-25 · How we research · Found an error? See our corrections policy.