Cyclic lipodepsipeptide antibiotic containing 13 amino acids and a decanoyl lipid tail from Streptomyces roseosporus — FDA-approved as Cubicin for complicated skin infections (2003) and S. aureus bacteremia including right-sided endocarditis (2006), operating through calcium-dependent phosphatidylglycerol-specific membrane depolarization with rapid bactericidal activity against MRSA, VRE, and other multidrug-resistant Gram-positive pathogens
Written by Michael Carroll — Owner, Director of Research · Reviewed by the Peptide Initiative Research Team · Editorial standards
Intravenous infusion over 30 minutes (on the FDA label; 60 minutes for younger children)
Route
3 recommended
Sites
Once daily
Frequency
Preparation
Daptomycin vial (lyophilized powder or solution)
Bacteriostatic water or sterile sodium chloride for reconstitution
Alcohol swabs for cleaning vial tops and injection sites
Appropriately sized syringes with fine-gauge needles (27-30 gauge)
Sharps disposal container
Pro tip
Prepare all supplies on a clean surface before you begin. Having everything ready makes the process smoother and more sterile.
Mixing
Wash your hands thoroughly with soap and water. Gather all supplies on a clean, flat surface.
Remove the plastic cap from the peptide vial and wipe the rubber stopper with an alcohol swab. Let it air dry.
Draw the appropriate amount of bacteriostatic water into a sterile syringe.
Insert the needle into the vial at an angle, aiming at the inside wall of the vial. Slowly push the plunger to let the water trickle down the glass wall -- do NOT squirt directly onto the powder.
Once all water is added, gently swirl the vial in a slow circular motion. Never shake the vial, as this can damage the peptide bonds.
Continue swirling until the powder is completely dissolved and the solution is clear. If particles remain, let the vial sit for a few minutes and swirl again.
Label the vial with the date of reconstitution, the peptide name, and the concentration (e.g. 250mcg per 0.1mL).
Example calculation
Add the recommended volume of bacteriostatic water to the Daptomycin vial. Gently swirl (do not shake) until the powder is fully dissolved. The resulting solution should be clear. Calculate your individual dose based on the concentration and your prescribed amount.
Dose calculation
Your dose of Daptomycin is determined by your healthcare provider. Using an insulin syringe marked in units, draw up the exact amount prescribed. For example, if the reconstituted concentration is 1mg/mL and your dose is 0.5mg, draw up 0.5mL (50 units on an insulin syringe). Always double-check calculations before injection.
Pro tip
Always add the bacteriostatic water slowly, letting it run down the side of the vial. Never shake the vial -- swirl gently to avoid damaging the peptide.
Location
Site 01
Abdomen
Pinch the skin 2 inches from navel. Avoid the area directly around the belly button. Rotate between left and right sides.
Site 02
Outer Thigh
Middle third of the outer thigh. Keep at least 4 inches above the knee and below the hip. Alternate legs each injection.
Site 03
Upper Arm
Back or outer area of the upper arm. This site may require assistance from another person for proper technique.
Rotate between 3 sites to prevent tissue buildup and ensure consistent absorption.
Pro tip
Rotate your injection sites with each dose to prevent lipohypertrophy (buildup of fatty tissue). Keep a simple log of where you last injected.
Step by step
Wash your hands thoroughly with soap and water before handling supplies
Clean the injection site with an alcohol swab and let it air dry completely
Pinch a fold of skin at the chosen injection site
Insert the needle at a 45-90 degree angle (depending on needle length and body composition)
Inject the medication slowly and steadily over 5-10 seconds
Release the skin fold and remove the needle, applying gentle pressure with a clean swab
Rotate injection sites to prevent tissue irritation or lipodystrophy
Dispose of the needle safely in a sharps container—never recap or reuse needles
Pro tip
This peptide uses subcutaneous injection (into the fatty tissue just under the skin)—allows for consistent absorption and can be self-administered at home after proper training. Inject at a 45-90 degree angle into pinched skin. Aspirate before injecting to ensure you haven't hit a blood vessel.
Timing
Optimal timing
Best time
Daptomycin is administered intravenously in a clinical setting. Timing is determined by your healthcare provider based on the treatment protocol and your medical needs.
With food?
IV administration of Daptomycin is not dependent on meal timing. Your healthcare team will provide specific instructions regarding food and fluid intake around treatment sessions.
Stacking notes
Daptomycin should be used as directed by your healthcare provider. If combining with other medications or supplements, discuss potential interactions with your provider. Avoid combining with compounds that have overlapping mechanisms unless specifically guided by a medical professional.
Sample daily schedule
As prescribed (once daily)
As prescribed by your healthcare provider injection
Site: Intravenous infusion over 30 minutes (FDA-approved)—rotate sites if applicable
Maintain a consistent schedule for optimal results with Daptomycin. Set reminders if needed. If you miss a dose, follow your healthcare provider's instructions—do not double up on doses to compensate.
Dosing tiers
Dose
4 mg/kg
Frequency
Once every 24 hours
Duration
7–14 days
The FDA-approved adult dose for complicated skin and skin-structure infections: 4 mg/kg every 24 hours for 7 to 14 days, intravenously in 0.9% sodium chloride, either as a 2-minute injection or a 30-minute infusion [6]. Below a creatinine clearance of 30 mL/min — including haemodialysis and CAPD — the same dose moves to every 48 hours, given after dialysis on dialysis days [6].
Dose
6 mg/kg
Frequency
Once every 24 hours
Duration
2–6 weeks
The FDA-approved adult dose for Staphylococcus aureus bloodstream infection, including right-sided infective endocarditis: 6 mg/kg every 24 hours for 2 to 6 weeks, every 48 hours below a creatinine clearance of 30 mL/min [6]. It is NOT approved for left-sided infective endocarditis, and NOT for pneumonia — pulmonary surfactant inactivates the drug directly [1][6].
Dose
8–12 mg/kg
Frequency
Once every 24 hours
Duration
2–6 weeks
Off-label in adults, and on-label in small children — the same numbers mean different things depending on who is being dosed. For children the label sets 12 mg/kg every 24 hours for ages 1 to 6 with S. aureus bacteraemia, 9 mg/kg for 7 to 11 and 7 mg/kg for 12 to 17, because clearance is faster [6]. In adults, above 6 mg/kg is off-label. The meta-analysis is not equivocal about the trade-off: in complicated bacteraemia and infective endocarditis, standard dosing succeeded significantly LESS often than high dosing (odds ratio 0.48, 95% CI 0.30-0.76 and 0.50, 0.30-0.82), and less often still against 8 mg/kg or more (0.38, 0.21-0.69 and 0.30, 0.15-0.60) — while the incidence of raised CPK was significantly lower on standard dosing [5]. In osteomyelitis and prosthetic infection, standard dosing did not do worse [5]. The label requires weekly CPK monitoring, more often in renal impairment or alongside a statin [6].
Preservation
Before mixing
Store Daptomycin in the refrigerator at 36-46°F (2-8°C) in its original packaging. Protect from light and moisture. Do not freeze. Check the expiration date before use. Some formulations may be stored at room temperature for limited periods—check your specific product labeling.
After mixing
Once reconstituted, Daptomycin should be kept refrigerated at 36-46°F (2-8°C) and used within the timeframe specified on your product labeling (typically 14-28 days). Label the vial with the reconstitution date. Do not use if the solution appears cloudy, discolored, or contains particles.
Shelf life after mixing
12 hours at room temperature; 48 hours refrigerated (reconstituted); check expiration on commercial vials (typically 2-3 years for lyophilized powder)
Signs of degradation
Discard the vial immediately if you notice any of these:
Solution appears cloudy, discolored, or contains visible particles (should be clear)
Product has been exposed to temperatures outside the recommended storage range
Product has been frozen (unless specifically designed for freeze-thaw stability)
Expiration date has passed or reconstituted solution has exceeded its use-by date
Unusual odor, color change, or visible contamination
Important
When to stop
Severe or worsening side effects that don't improve with dose adjustment or supportive care
Signs of an allergic reaction—rash, hives, swelling, or difficulty breathing
Your healthcare provider recommends discontinuation based on your clinical response
Development of any new medical condition that may be contraindicated with Daptomycin
Pregnancy or planning to become pregnant (unless specifically approved for use during pregnancy)
Abnormal lab results or clinical markers that suggest adverse effects
Daptomycin should only be started, adjusted, or discontinued under medical supervision. This information is for educational purposes only and does not replace professional medical advice. Never stop a prescribed treatment without consulting your healthcare provider first, as abrupt discontinuation may have consequences.
Clean technique checklist
Wash hands thoroughly with soap and water before handling supplies
Swab vial tops and injection site with alcohol and let dry
Never touch the needle tip or allow it to contact non-sterile surfaces
Use a new syringe and needle for each injection
Dispose of used sharps in a proper sharps container
Store reconstituted peptides according to the storage instructions above
Published research
Silverman JA, Mortin LI, VanPraagh ADG, Li T, Alder J · 2005
Why daptomycin must never be used for pneumonia, and the paper that explains it. Daptomycin failed to meet non-inferiority criteria in a trial for severe community-acquired pneumonia, and showed an odd pattern in animal models — it worked in Staphylococcus aureus haematogenous pneumonia and inhalation anthrax but had no activity against Streptococcus pneumoniae in simple bronchial-alveolar pneumonia. The reason is that pulmonary surfactant inhibits it directly, an effect specific to daptomycin and consistent with its membrane mechanism. The authors call this the first example of organ-specific inhibition of an antibiotic. It is why the FDA label states plainly that daptomycin is not indicated for the treatment of pneumonia [6].
Bland CM, Bookstaver PB, Lu ZK, Dunn BL, Rumley KF · 2014
The statin question, with both arms. A multicentre retrospective study across 13 institutions compared 49 adults receiving a statin alongside daptomycin with 171 receiving daptomycin alone. Myalgias occurred in 3 of 49 (6.1%) on the combination against 5 of 171 (2.9%) on daptomycin alone (p=0.38). CPK above 1,000 U/L occurred in 5 of 49 (10.2%) against 9 of 171 (5.3%) (p=0.32), and 2 of those 5 had myopathy symptoms. Three patients (6.1%) stopped because of CPK elevation with myalgia against 6 (3.5%) in the daptomycin-alone group (p=0.42). CPK and myalgias reversed on stopping daptomycin. Musculoskeletal toxicity was numerically higher on the combination but not statistically so — a study this size could not settle it, which is why the label still asks for more frequent CPK monitoring in patients on a statin [6].
Lee MT, Yang PY, Charron NE, Hsieh MH, Chang YY, Huang HW · 2018
Laboratory work on how daptomycin actually acts on a membrane, and a correction of the textbook picture: the study it builds on disproved the existence of daptomycin ion channels. Using aspirated giant vesicles, the authors found daptomycin causes ion leakage only above a threshold concentration in the membrane, only transiently, and only on first binding — after that the same molecules cease to induce leakage, and the effect cannot be transferred from one membrane to another. Binding is weaker in gel-phase bilayers and weaker again with cholesterol present, which the authors suggest is part of why daptomycin discriminates between bacterial and human cell membranes. This is model-membrane biophysics, not a clinical result.
Iwata S, Koyama H, Murata Y · 2021
An open-label single-arm phase 2 study in 18 Japanese children aged 1 to 17 (14 with complicated skin and soft tissue infection, 4 with bacteraemia), given age-adjusted intravenous daptomycin for 5 to 14 days or 5 to 42 days respectively. Adverse events were reported in 6 of 14 (42.9%) of the skin-infection group and 4 of 4 (100%) of the bacteraemia group, but there were no deaths, no serious adverse events and no discontinuations for adverse events. Among the 8 participants with MRSA, 7 (87.5%) had a favourable clinical response at test of cure. Eighteen children with no control arm — supportive, not decisive.
Samura M, Takada K, Hirose N, Kurata T, Nagumo F, Uchida M, et al. · 2023
The paper that settles the high-dose question, and it cuts both ways. Pooling across four databases, standard dose (4-6 mg/kg) was compared with high dose (above 6 mg/kg) and with 8 mg/kg or more. In complicated bacteraemia and infective endocarditis, treatment success was significantly LOWER on standard dose than on high dose (odds ratio 0.48, 95% CI 0.30-0.76 for complicated bacteraemia; 0.50, 0.30-0.82 for endocarditis) and lower still against the 8 mg/kg or more group (0.38, 0.21-0.69 and 0.30, 0.15-0.60). For osteomyelitis and foreign-body or prosthetic infection, standard dose did not do worse. The cost is measurable: the incidence of elevated CPK was significantly lower on standard dose than on high dose. So high dose buys success in complicated bloodstream infection and endocarditis, and pays for it in muscle enzyme elevation.
U.S. Food and Drug Administration; NorthStar Rx LLC · 2024
Indicated for complicated skin and skin-structure infections in adults and children aged 1 to 17, and for Staphylococcus aureus bloodstream infection in adults (including right-sided infective endocarditis) and in children aged 1 to 17. Three limitations of use matter more than the indications: it is NOT indicated for pneumonia, NOT indicated for LEFT-sided infective endocarditis due to S. aureus, and NOT recommended below one year of age because of effects on muscular, neuromuscular and nervous systems seen in neonatal dogs. Adult dosing is 4 mg/kg every 24 hours for 7-14 days in skin infection and 6 mg/kg every 24 hours for 2-6 weeks in bacteraemia, moving to every 48 hours below a creatinine clearance of 30 mL/min including haemodialysis and CAPD, given after dialysis on dialysis days. Warnings cover anaphylaxis, myopathy and rhabdomyolysis, eosinophilic pneumonia, DRESS, tubulointerstitial nephritis, peripheral neuropathy, Clostridioides difficile diarrhoea, and reduced efficacy in moderate baseline renal impairment. The only contraindication is known hypersensitivity to daptomycin.
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