Peptide Profile
Daptomycin
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
Dose Range
4-6mg/kg
Frequency
Once daily
Route
Intravenous infusion over 30 minutes (FDA-approved)
Cycle Length
4-6 weeks
Onset
Rapid (hours to days)
Evidence
Strong
Compound Profile
Scientific & Efficacy Data
C₇₂H₁₀₁N₁₇O₂₆
Molecular Formula
1,620.69 Da
Molecular Weight
Terminal half-life: 8-9 hours in healthy adults with normal renal function; supports once-daily dosing; post-antibiotic effect: 1-6 hours against S. aureus; renal dose adjustment: CrCl <30 mL/min — extend interval to every 48 hours
Half-Life
IV: 100% (direct administration); not orally bioavailable (degraded in GI tract); inactivated in lungs by pulmonary surfactant
Bioavailability
103060-53-3
CAS #
21585658
PubChem ID ↗
Developed By · 1980s (discovery by Eli Lilly); 2003 (FDA approval for cSSSI); 2006 (FDA approval for bacteremia/endocarditis)
Cubist Pharmaceuticals
Cubist Pharmaceuticals (Merck)
Primary Benefits
Amino Acid Sequence
Decanoyl-LTPIKDVGRLLTGYVDGGQQVLTGSDosing
How much
do I take?
Starting Dose
4 mg/kg IV once daily
FDA-approved dose for complicated skin and skin structure infections (cSSSI). Administer as 30-minute IV infusion or 2-minute IV push. Obtain baseline CPK before starting therapy. Monitor CPK weekly (more often if concurrent statins or symptoms of myopathy). Consider temporarily discontinuing statins during daptomycin therapy. Dose adjust for renal impairment: CrCl <30 mL/min — 4 mg/kg every 48 hours. Can be administered as OPAT.
Standard Dose
6 mg/kg IV once daily
FDA-approved dose for S. aureus bacteremia including right-sided infective endocarditis. Duration guided by clinical response: minimum 2 weeks for uncomplicated bacteremia, 4-6 weeks for endocarditis. Monitor CPK weekly. Repeat blood cultures every 48-72 hours until clearance. If bacteremia persists beyond 5-7 days, consider higher doses (8-10 mg/kg off-label) or combination therapy with ceftaroline or beta-lactam (seesaw effect).
Advanced Dose
8-12 mg/kg IV once daily (off-label high-dose)
Off-label high-dose daptomycin used for persistent MRSA bacteremia, endocarditis with high vancomycin MICs, and complex osteoarticular infections. Multiple retrospective studies support safety and efficacy of doses up to 10-12 mg/kg. Monitor CPK at least weekly, more frequently at higher doses. Often combined with ceftaroline (seesaw synergy) or rifampicin (biofilm activity) for persistent infections. Infectious disease specialist management required.
Timing
Best time to take
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.
If stacking
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.
Adjusting Your Dose
Increase if
- +You've tolerated the current dose for the recommended period without significant side effects
- +Therapeutic goals haven't been met at the current dose level
- +Your healthcare provider recommends dose escalation based on your response
- +Lab work or clinical assessments support a higher dose
Decrease if
- -Side effects are bothersome or impacting daily life despite management strategies
- -You experience any signs of an adverse reaction
- -Lab results indicate the need for dose reduction
- -Your healthcare provider recommends a lower dose based on your response
Signs of right dose
- ✓Therapeutic goals being met with minimal side effects
- ✓Stable and consistent response to treatment
- ✓Lab values or clinical markers trending in the right direction
- ✓Good tolerance with manageable or absent side effects
Dosing Calculator
Calculate Your Exact Dose
Step 1: Peptide Weight
Find the weight printed on your peptide vial label
Look here!
The peptide weight is printed on the label
Look here!
The weight is on the label
Suitability
Is this
right for me?
Best For
Treatment of MRSA bacteremia and right-sided infective endocarditis (FDA-approved indication at 6 mg/kg)
Daptomycin is particularly well-suited for individuals focused on treatment of mrsa bacteremia and right-sided infective endocarditis (fda-approved indication at 6 mg/kg). Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Complicated skin and skin structure infections including surgical site infections and diabetic foot infections (FDA-approved at 4 mg/kg)
Daptomycin is particularly well-suited for individuals focused on complicated skin and skin structure infections including surgical site infections and diabetic foot infections (fda-approved at 4 mg/kg). Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
VRE bloodstream infections and endocarditis when ampicillin-based therapy is not feasible
Daptomycin is particularly well-suited for individuals focused on vre bloodstream infections and endocarditis when ampicillin-based therapy is not feasible. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Outpatient parenteral antibiotic therapy (OPAT) for Gram-positive infections requiring IV treatment
Daptomycin is particularly well-suited for individuals focused on outpatient parenteral antibiotic therapy (opat) for gram-positive infections requiring iv treatment. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Consider Alternatives If
Who Should Avoid
Do not use if
- ×Known hypersensitivity to daptomycin or any component of the formulation
- ×Pneumonia or any lower respiratory tract infection — daptomycin is inactivated by pulmonary surfactant (phosphatidylcholine) and will fail to treat pneumonia
- ×Concurrent use of HMG-CoA reductase inhibitors (statins) is relatively contraindicated — consider temporary discontinuation to reduce risk of additive myotoxicity
- ×Pre-existing significant skeletal muscle disease or unexplained CPK elevation >5x ULN
Use with caution if
- !You are taking other medications—discuss potential interactions with your healthcare provider
- !You have a history of liver or kidney disease
- !You are elderly or have multiple medical conditions
- !You are planning surgery in the near future—inform your surgeon about Daptomycin use
- !You have any chronic health conditions that require regular monitoring
Administration
How do I
use it?
Reconstitution
What you need
- •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
Injection
Route
Subcutaneous injection (into the fatty tissue just under the skin)—allows for consistent absorption and can be self-administered at home after proper training
Best sites
- •Abdomen (stomach area)—at least 2 inches from the belly button, most popular choice for self-injection
- •Front of thighs—middle to upper portion of the outer leg
- •Back of upper arm—outer area (may need assistance from another person)
Technique
- 1.Wash your hands thoroughly with soap and water before handling supplies
- 2.Clean the injection site with an alcohol swab and let it air dry completely
- 3.Pinch a fold of skin at the chosen injection site
- 4.Insert the needle at a 45-90 degree angle (depending on needle length and body composition)
- 5.Inject the medication slowly and steadily over 5-10 seconds
- 6.Release the skin fold and remove the needle, applying gentle pressure with a clean swab
- 7.Rotate injection sites to prevent tissue irritation or lipodystrophy
- 8.Dispose of the needle safely in a sharps container—never recap or reuse needles
Storage
Signs of degradation
Sample Daily Schedule
Safety
Is it
safe?
Safety Profile
Daptomycin is an FDA-approved antibiotic with extensive clinical safety data from Phase 2/3 trials and post-market pharmacovigilance spanning over 20 years. Key safety concerns include muscle toxicity (creatine phosphokinase elevation) occurring in 3-12% of treated patients, potentially progressing to myopathy with weakness if unmonitored. Pulmonary toxicity (eosinophilic pneumonia) is rare (<1%) but serious. Peripheral neuropathy, nausea, and injection site reactions are common but usually mild. Creatinine elevation in renal impairment is significant—dosing must be reduced in patients with eGFR <30 mL/min. CPK monitoring is essential during treatment, especially in patients on statins or with baseline elevations.
Daptomycin was studied through Phase 2 and Phase 3 clinical trials for bacterial infections including bacteremia and endocarditis, with FDA approval based on large multicenter randomized controlled trials. Post-marketing surveillance data spans 20+ years of widespread clinical use. Adverse event monitoring is well-established, and risk factors for myopathy and pulmonary toxicity are well-characterized.
Common Side Effects
Experienced by some users
CPK elevation
Asymptomatic creatine phosphokinase (CPK) elevation reported in 5.3-10.2% of patients, reflecting daptomycin's interaction with skeletal muscle phospholipid membranes. Usually mild (<5x ULN) and reversible.
Management: Monitor CPK weekly (baseline + weekly during therapy). If CPK >5x ULN with symptoms (myalgia, weakness), discontinue daptomycin. If CPK >10x ULN even without symptoms, strongly consider discontinuation. Temporarily discontinue statins during therapy.
GI effects (nausea, diarrhea, vomiting)
Nausea (5.8%), diarrhea (5.2%), vomiting (3.2%), and constipation are the most common non-skeletal adverse effects.
Management: Usually mild and self-limiting. Antiemetics for nausea if needed. Monitor for C. difficile infection if diarrhea is persistent or severe. Adequate hydration.
Headache and insomnia
Headache reported in 5.4% and insomnia in 4.5% of patients in clinical trials.
Management: Standard analgesics for headache. Sleep hygiene measures for insomnia. Usually resolve during treatment or after completion.
Injection site reactions
Pain, erythema, and mild phlebitis at the IV infusion site in 5.8% of patients.
Management: Rotate infusion sites. Use large-bore vein if available. 2-minute IV push may be better tolerated than 30-minute infusion for some patients.
Less Common
- •Eosinophilic pneumonia
These typically resolve with continued use or dose adjustment.
Stop and Seek Help If
- ×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.
Interactions
With other peptides
- ✓May be used together under medical guidance.
- ✓May be used together under medical guidance.
- ✓May be used together under medical guidance.
With medications
- !Statins (HMG-CoA reductase inhibitors) — additive myotoxicity risk with daptomycin; consider temporary statin discontinuation during daptomycin therapy or monitor CPK more frequently - Use with caution—discuss with your healthcare provider.
- !Tobramycin (in vitro antagonism demonstrated when co-administered with daptomycin for certain organisms — potential reduced efficacy) - Use with caution—discuss with your healthcare provider.
- !Use for pneumonia or respiratory infections — daptomycin is inactivated by pulmonary surfactant; this is an absolute clinical restriction, not a drug interaction - Use with caution—discuss with your healthcare provider.
With supplements
- ✓Multivitamins - Generally safe to take alongside Daptomycin. Space doses apart if taking oral formulations to ensure optimal absorption.
- ✓Electrolyte supplements - Helpful if experiencing any GI side effects that could lead to dehydration. Safe to combine.
Effectiveness
Does it
work?
Evidence Level
Strong human trials
What to Expect
Hours 0-48 (initiation)
What you might notice
- •IV infusion generally well-tolerated; mild injection site discomfort possible
- •Bactericidal activity begins within hours of achieving therapeutic levels
- •Baseline CPK obtained for monitoring
- •Nausea or headache may occur with first doses
What's normal
- •Daptomycin achieves peak bactericidal activity within the first 24 hours
- •For bacteremia, blood cultures should be repeated at 48-72 hours to assess clearance
- •Once-daily dosing is established from the start — no loading dose needed
- •Mild GI effects are common initially and usually transient
What's next
- →Continue daily IV dosing per indicated schedule
- →Repeat blood cultures at 48-72 hours for bacteremia
- →First CPK check at day 3-7
- →Assess clinical response (fever, WBC, hemodynamics) at 48-72 hours
Days 3-14 (active treatment)
What you might notice
- •Clinical improvement: defervescence, resolving signs of infection
- •Blood culture clearance expected by day 3-5 for susceptible organisms
- •CPK may show mild elevation — usually asymptomatic
- •For cSSSI: visible improvement in skin infection by day 3-4
What's normal
- •cSSSI treatment typically completed in 7-14 days
- •Bacteremia clearance should occur by day 3-5; if persistent, reassess
- •Mild CPK elevation is common and not necessarily an indication to stop
- •Once-daily dosing may allow OPAT transition for clinically stable patients
What's next
- →Continue weekly CPK monitoring throughout treatment
- →For cSSSI: complete 7-14 day course as clinically indicated
- →For bacteremia: continue until 2 weeks after first negative blood culture
- →For endocarditis: plan for 4-6 week total treatment course
Week 2-6 (extended treatment/completion)
What you might notice
- •Infection resolving or resolved depending on indication
- •Endocarditis patients: continued improvement on echocardiographic follow-up
- •CPK typically returns to normal within 1 week of completing therapy
- •Overall recovery and return to baseline function
What's normal
- •Extended courses (4-6 weeks) are standard for endocarditis and osteoarticular infections
- •OPAT allows patients to receive remaining treatment at home
- •CPK should be monitored weekly through end of therapy
- •Post-treatment relapse surveillance is recommended for endocarditis
What's next
- →Complete the full treatment course per infectious disease guidance
- →Final CPK check at end of treatment to confirm normalization
- →Resume statins if held during daptomycin therapy (after 1 week off daptomycin)
- →Follow-up blood cultures and clinical assessment post-treatment
Signs It's Working
Treatment Response
- ✓Improvement in the primary symptoms or condition being treated
- ✓Positive changes in relevant lab values or clinical markers
- ✓Consistent, stable response to Daptomycin over time
- ✓Reduction in symptom frequency or severity
General Well-being
- ✓Improved energy levels and daily functioning
- ✓Better quality of life related to the treated condition
- ✓Manageable or absent side effects indicating good tolerance
- ✓Positive feedback from healthcare provider during check-ups
Not Seeing Results?
Common reasons
- •Not at therapeutic dose yet—initial doses are for building tolerance, not maximum effect
- •Insufficient time at target dose—most compounds need several weeks to show full benefits
- •Inconsistent dosing schedule—regular, consistent use is crucial for optimal results
- •Individual variation in response—genetics, metabolism, and other factors affect outcomes
- •Underlying conditions or medications interfering with absorption or effectiveness
- •Improper storage leading to degraded product—always verify proper storage conditions
Key Research
"Daptomycin versus standard-of-care for the treatment of complicated skin and skin-structure infections — Phase III randomized trial"
Arbeit RD, Maki D, Tally FP, Campanaro E, Eisenstein BI, 2004
Finding: Daptomycin loses its antimicrobial power when it contacts lung surfactant—a unique limitation that explains why it failed in pneumonia treatment despite working well for skin infections.
View Study"Daptomycin for the treatment of Staphylococcus aureus bacteremia and endocarditis"
Fowler VG, Boucher HW, Corey GR, Abrutyn E, Karchmer AW, Rupp ME, 2006
Finding: Clinical evidence (2006) supports the therapeutic use of daptomycin in medical treatment protocols.
View Study"High-dose daptomycin for persistent MRSA bacteremia: safety and efficacy analysis"
Kullar R, Davis SL, Levine DP, Rybak MJ, 2011
Finding: Research (2011) demonstrates daptomycin's efficacy in clinical treatment and therapeutic applications.
View Study"Daptomycin plus ceftaroline combination therapy for persistent MRSA bacteremia — the seesaw effect"
Sakoulas G, Moise PA, Casapao AM, Nonejuie P, 2014
Finding: Clinical evidence (2014) supports the therapeutic use of daptomycin in medical treatment protocols.
View Study"Mechanism of action of daptomycin: calcium-dependent membrane depolarization and phosphatidylglycerol targeting"
Silverman JA, Perlmutter NG, Shapiro HM, 2003
Finding: Study (2003) elucidates the molecular mechanism of action and biological pathways by which daptomycin produces therapeutic effects.
View StudyFrequently Asked Questions