Cubicin (Daptomycin)
Cyclic lipopeptide antibiotic for serious Gram-positive infections
Quick Facts About Cubicin (Daptomycin)
Key Takeaways About Cubicin
- Effective against MRSA: Daptomycin is one of the first-line treatments for serious MRSA infections including bacteremia and right-sided endocarditis
- Not for pneumonia: Cubicin is inactivated by pulmonary surfactant and must not be used to treat lung infections
- Monitor CPK levels: Weekly creatine phosphokinase (CPK) blood tests are required during treatment to detect muscle toxicity early
- Pause statins during treatment: Concurrent use of statins increases the risk of muscle damage; temporary discontinuation is generally recommended
- Unique mechanism of action: Daptomycin works by disrupting the bacterial cell membrane, making cross-resistance with other antibiotics uncommon
What Is Cubicin and What Is It Used For?
Cubicin (daptomycin) is a cyclic lipopeptide antibiotic that kills bacteria by disrupting their cell membranes. It is used to treat complicated skin and soft tissue infections in adults and children (aged 1–17), and Staphylococcus aureus bacteremia and right-sided endocarditis in adults.
Daptomycin, the active ingredient in Cubicin, belongs to a unique class of antibiotics known as cyclic lipopeptides. Unlike many other antibiotics that target protein synthesis or cell wall construction, daptomycin works through a distinct mechanism: it binds to bacterial cell membranes in a calcium-dependent process, causing rapid depolarization of the membrane potential. This membrane disruption leads to the inhibition of protein, DNA, and RNA synthesis simultaneously, resulting in swift bacterial cell death without cell lysis. This bactericidal action is concentration-dependent, meaning higher concentrations achieve faster and more complete bacterial killing.
Cubicin is specifically approved for the treatment of complicated skin and skin structure infections (cSSTI) caused by susceptible Gram-positive organisms, including Staphylococcus aureus (both methicillin-susceptible and methicillin-resistant strains), Streptococcus pyogenes, Streptococcus agalactiae, Streptococcus dysgalactiae, and Enterococcus faecalis (vancomycin-susceptible strains only). These infections may include deep soft tissue infections, surgical wound infections, major abscesses, and infected diabetic foot ulcers.
In adult patients, Cubicin is also indicated for the treatment of Staphylococcus aureus bloodstream infections (bacteremia), including those associated with right-sided infective endocarditis. Endocarditis is a serious infection of the inner lining of the heart chambers and valves. It is important to note that the efficacy of daptomycin has been demonstrated specifically for right-sided endocarditis; there are limited data supporting its use for left-sided endocarditis, and it is generally not recommended for that indication without specialist consultation.
Depending on the type and severity of infection, your physician may prescribe additional antibacterial agents alongside Cubicin to ensure optimal treatment outcomes. Combination therapy is particularly common in severe or complicated infections where broader coverage is warranted.
Cubicin must not be used to treat pneumonia or other lung infections. Daptomycin is inactivated by pulmonary surfactant, a substance naturally present in the lungs, which renders the antibiotic ineffective against respiratory pathogens. Clinical trials confirmed that daptomycin did not meet non-inferiority criteria for community-acquired pneumonia. Alternative antibiotics must be used for respiratory tract infections.
What Should You Know Before Taking Cubicin?
Before receiving Cubicin, inform your doctor about any kidney problems, muscle disorders, previous allergic reactions to daptomycin, current medications (especially statins), and if you are pregnant or breastfeeding. Regular blood tests to monitor kidney function and muscle enzymes (CPK) are required throughout treatment.
Contraindications
You must not receive Cubicin if you are allergic to daptomycin, sodium hydroxide, or any other ingredients in this medicine. Hypersensitivity to daptomycin can manifest as anaphylaxis, angioedema, or severe skin reactions, and any prior history of such reactions is an absolute contraindication to further use. If you suspect you may be allergic, discuss this with your physician before treatment begins.
Warnings and Precautions
Several important precautions should be discussed with your healthcare provider before starting Cubicin therapy:
Kidney impairment: If you have or have previously had kidney problems, your doctor may need to adjust your dose of Cubicin. Daptomycin is primarily eliminated through the kidneys, and reduced kidney function can lead to higher drug levels in the blood, potentially increasing the risk of side effects. Patients with severe kidney impairment or those receiving dialysis require modified dosing schedules, typically receiving Cubicin every 48 hours rather than daily.
Muscle toxicity: In some cases, patients treated with Cubicin develop muscle soreness, pain, or weakness. This is one of the most clinically significant adverse effects of daptomycin. If you experience these symptoms, inform your doctor immediately. Blood tests measuring creatine phosphokinase (CPK) will be performed to assess muscle damage. Your doctor will determine whether to continue treatment based on CPK levels and clinical symptoms. Muscle-related symptoms typically resolve within a few days of stopping Cubicin.
Obesity: If you are significantly overweight, blood levels of Cubicin may be higher than in average-weight individuals. Your healthcare team may need to monitor you more closely for potential side effects and adjust dosing based on actual body weight calculations.
Previous severe skin reactions: If you have ever experienced severe skin rashes, skin peeling, blistering, or mouth sores after taking daptomycin, you should not receive Cubicin again. Serious dermatological reactions, though rare, can be life-threatening and require immediate medical attention.
- Severe allergic reactions: wheezing, difficulty breathing, swelling of the face, neck, or throat, skin rash, hives, or fever
- Serious skin reactions: new or worsening fever, red raised or fluid-filled skin spots, blisters or sores in the mouth or on the genitals
- Kidney problems: fever accompanied by a new rash
- Nerve symptoms: unusual tingling or numbness in the hands or feet, loss of sensation or difficulty moving
- Diarrhea: especially if bloody or mucoid, or if it becomes severe or persistent
- Respiratory symptoms: new or worsening fever, cough, or breathing difficulties (may indicate eosinophilic pneumonia)
Your doctor will take blood tests to monitor your muscles both before starting treatment and at regular intervals during Cubicin therapy. CPK levels are typically checked at baseline and at least weekly thereafter, with more frequent monitoring in patients at higher risk for muscle toxicity.
Use in Children and Elderly Patients
Cubicin is approved for use in children and adolescents aged 1 to 17 years for the treatment of complicated skin and soft tissue infections. It should not be given to children under 1 year of age, as animal studies have indicated that this age group may experience severe adverse effects, including effects on the muscular and nervous systems.
Elderly patients (over 65 years) may receive the same dose as other adults, provided their kidney function is adequate. Since kidney function naturally declines with age, older patients may require dose adjustments, and closer monitoring of renal function and CPK levels is recommended.
Pregnancy and Breastfeeding
Cubicin is not normally administered to pregnant women due to insufficient data on its safety during pregnancy. If you are pregnant, think you may be pregnant, or are planning to have a baby, consult your doctor before receiving this medicine. Animal reproductive studies have not demonstrated teratogenic effects, but the absence of well-controlled human studies means that daptomycin should only be used during pregnancy if the potential benefit justifies the potential risk to the fetus.
You should not breastfeed while being treated with Cubicin. Daptomycin is excreted in human breast milk in low concentrations, and its effects on the nursing infant have not been adequately studied. The potential for serious adverse reactions in breastfed infants necessitates a decision to either discontinue breastfeeding or avoid Cubicin treatment, taking into account the importance of the drug to the mother.
Driving and Operating Machinery
Cubicin is not known to affect the ability to drive or use machines. However, as with any intravenous antibiotic, some patients may experience dizziness or other central nervous system effects. If you experience such symptoms, avoid driving or operating machinery until these effects resolve.
Cubicin contains less than 1 mmol (23 mg) of sodium per dose, making it essentially sodium-free. This is relevant for patients on sodium-restricted diets or with conditions requiring careful sodium monitoring.
How Does Cubicin Interact with Other Drugs?
Cubicin can interact with statins, fibrates, ciclosporin, NSAIDs, COX-2 inhibitors, and oral anticoagulants like warfarin. The most clinically significant interaction involves drugs that can cause muscle toxicity (statins, fibrates), as concurrent use may increase the risk of myopathy and rhabdomyolysis.
Drug interactions with Cubicin are clinically important and require careful management. Tell your doctor about all medications you are currently taking, have recently taken, or plan to take. This includes prescription medications, over-the-counter drugs, vitamins, and herbal supplements.
Major Interactions
| Drug/Class | Interaction | Clinical Action |
|---|---|---|
| Statins (e.g., atorvastatin, simvastatin, rosuvastatin) | Both statins and daptomycin can cause muscle damage (elevated CPK, myopathy). Additive risk of rhabdomyolysis. | Temporarily discontinue statin therapy during Cubicin treatment. Resume after completing the antibiotic course. |
| Fibrates (e.g., gemfibrozil, fenofibrate) | Fibrates also carry risk of myopathy. Combined use with daptomycin increases muscle toxicity risk. | Temporarily suspend fibrate therapy during Cubicin treatment if clinically appropriate. |
| Ciclosporin | May increase daptomycin exposure and enhance the risk of muscle-related adverse effects. | Monitor CPK levels more frequently. Consider dose adjustment if clinically warranted. |
Moderate Interactions
| Drug/Class | Interaction | Clinical Action |
|---|---|---|
| NSAIDs (e.g., ibuprofen, diclofenac) | NSAIDs may affect kidney function, potentially altering the renal excretion of daptomycin. | Monitor renal function closely if concurrent use is necessary. |
| COX-2 inhibitors (e.g., celecoxib) | Similar to NSAIDs, COX-2 inhibitors may impair renal clearance of daptomycin. | Assess kidney function regularly during concurrent administration. |
| Warfarin (oral anticoagulant) | Daptomycin may interfere with certain coagulation assays (prolonged PT/INR), leading to falsely abnormal results. | Your doctor may need to monitor your blood clotting time more frequently and use alternative coagulation assays. |
Cubicin can interfere with laboratory tests that measure blood clotting (coagulation). Specifically, daptomycin may cause a falsely prolonged prothrombin time (PT) and elevated international normalized ratio (INR) when certain recombinant thromboplastin reagents are used. This laboratory artifact does not reflect an actual coagulation disorder. If you are receiving Cubicin, it is important that your doctor is aware of this potential interference when interpreting coagulation test results.
What Is the Correct Dosage of Cubicin?
Cubicin is given intravenously once daily. Adults receive 4 mg/kg for skin infections or 6 mg/kg for bacteremia and endocarditis. Pediatric dosing varies by age group. Treatment typically lasts 1–2 weeks for skin infections, with duration for bacteremia and endocarditis determined individually.
Cubicin is always administered by a doctor or nurse in a healthcare setting. The medication is given directly into the bloodstream (intravenously), either as a 30-minute infusion or, in adults only, as a 2-minute injection. The reconstituted solution should be a clear, pale yellow to light brown liquid. The specific dosage depends on your weight and the type of infection being treated.
Adults (18 Years and Older)
| Indication | Dose | Frequency | Administration |
|---|---|---|---|
| Complicated skin and soft tissue infections (cSSTI) | 4 mg/kg | Once daily | IV infusion (30 min) or IV injection (2 min) |
| S. aureus bacteremia | 6 mg/kg | Once daily | IV infusion (30 min) or IV injection (2 min) |
| Right-sided infective endocarditis | 6 mg/kg | Once daily | IV infusion (30 min) or IV injection (2 min) |
The same dose recommendations apply to patients over 65 years of age, provided that their kidney function is adequate. No dose adjustment is needed based on age alone.
Patients with Kidney Impairment
If your kidney function is reduced (creatinine clearance less than 30 mL/min), your doctor will adjust the dosing frequency. Instead of receiving Cubicin daily, you may receive it every 48 hours (once every other day). For patients receiving hemodialysis or continuous ambulatory peritoneal dialysis (CAPD), Cubicin should ideally be administered after dialysis sessions on dialysis days, as the drug is partially removed during dialysis.
Children and Adolescents (1 to 17 Years)
Dosing for pediatric patients depends on the child's age group. It is important to note that in children, Cubicin must be given as an infusion only—the 2-minute IV injection is not approved for pediatric use.
| Age Group | Dose | Infusion Duration |
|---|---|---|
| 12–17 years | 5 mg/kg once daily | 30 minutes |
| 7–11 years | 7 mg/kg once daily | 30 minutes |
| 2–6 years | 9 mg/kg once daily | 60 minutes |
| 1–2 years | 12 mg/kg once daily | 60 minutes |
Children under 7 years of age receiving higher doses (9–12 mg/kg) require a longer infusion time of 60 minutes to ensure safe administration. Cubicin must not be used in children under 1 year of age.
Treatment Duration
A typical treatment course for skin infections lasts 1 to 2 weeks. For bloodstream infections or endocarditis, the duration of treatment is determined individually by your doctor based on clinical response, resolution of bacteremia, and guidelines from infectious disease specialists. Treatment courses for bacteremia and endocarditis are often significantly longer, frequently extending to 4–6 weeks or more depending on clinical response and complications.
Cubicin must only be reconstituted with 0.9% sodium chloride solution. It is not compatible with glucose-containing solutions. The reconstituted solution may be stored for up to 12 hours at 25°C or up to 24 hours refrigerated (2–8°C). Each vial is for single use only; any unused solution should be discarded.
What Are the Side Effects of Cubicin?
Like all antibiotics, Cubicin can cause side effects. The most clinically important are muscle toxicity (elevated CPK, myopathy, rhabdomyolysis), eosinophilic pneumonia, severe allergic reactions, and serious skin reactions. Common side effects include fungal infections, headache, nausea, diarrhea, and injection site reactions.
Not everyone who receives Cubicin will experience side effects, but it is important to be aware of potential reactions so that you can recognize and report them promptly. The side effects are categorized below by frequency, from most common to rarest. Your healthcare team will monitor you throughout treatment, but you should always report any unusual or concerning symptoms immediately.
The following serious adverse reactions have been reported with Cubicin. Contact your doctor or nurse immediately if you experience any of these:
- Severe allergic reactions (anaphylaxis): chest pain or tightness, rash or hives, throat swelling, rapid or weak pulse, wheezing, fever, chills, flushing, dizziness, fainting, or metallic taste in the mouth
- Unexplained muscle pain, tenderness, or weakness: may indicate rhabdomyolysis (muscle breakdown) which can lead to kidney damage
- Eosinophilic pneumonia: difficulty breathing, new or worsening cough, new or worsening fever (typically after >2 weeks of treatment)
- Serious skin reactions: widespread red, raised, or fluid-filled skin spots; blisters or sores in the mouth or on the genitals
- Severe kidney problems: fever accompanied by a new rash
Common Side Effects
Affects fewer than 1 in 10 patients
- Fungal infections (such as oral thrush, candidiasis)
- Urinary tract infection
- Decreased red blood cell count (anemia)
- Dizziness, anxiety, insomnia
- Headache
- Fever, weakness (asthenia)
- High or low blood pressure
- Constipation, abdominal pain
- Diarrhea, nausea, or vomiting
- Flatulence, abdominal distension or bloating
- Skin rash or itching
- Pain, itching, or redness at the injection site
- Pain in the arms or legs
- Elevated liver enzymes or creatine phosphokinase (CPK) in blood tests
Uncommon Side Effects
Affects fewer than 1 in 100 patients
- Blood disorders (increased platelets, elevated white blood cells)
- Decreased appetite
- Tingling or numbness in hands or feet, taste disturbances
- Tremor
- Changes in heart rhythm, flushing
- Indigestion (dyspepsia), tongue inflammation
- Itchy skin rash
- Muscle pain, cramps, weakness, or inflammation (myositis), joint pain
- Kidney problems
- Vaginal inflammation and irritation
- General pain or weakness, fatigue
- Elevated blood sugar, serum creatinine, myoglobin, or LDH in blood tests
- Prolonged blood clotting time, electrolyte imbalances
- Eye itching
Rare Side Effects
Affects fewer than 1 in 1,000 patients
- Jaundice (yellowing of the skin and eyes)
- Prolonged prothrombin time (coagulation time)
Frequency Not Known
Cannot be estimated from available data
- Antibiotic-associated colitis including pseudomembranous colitis (severe or prolonged diarrhea that is bloody or mucoid, with abdominal pain or fever)
- Increased tendency to bruise
- Bleeding gums or nosebleeds
If you experience any side effects, including any not listed above, talk to your doctor or nurse. You can also report suspected side effects to your national pharmacovigilance authority to contribute to the ongoing safety monitoring of medicines.
How Should You Store Cubicin?
Store unopened Cubicin vials in the refrigerator (2–8°C / 36–46°F). Keep out of reach of children. Do not use after the expiry date printed on the label. Once reconstituted, use within 12 hours at room temperature or 24 hours if refrigerated.
Cubicin powder for injection/infusion should be stored in a refrigerator at 2°C to 8°C (36°F to 46°F) in its original packaging until ready for use. The product should be kept out of the sight and reach of children at all times.
Do not use this medicine after the expiry date stated on the carton and vial label after “EXP.” The expiry date refers to the last day of that month. Once the powder has been reconstituted into a solution, it should be used promptly. The chemical and physical stability of the reconstituted solution has been demonstrated for:
- 12 hours at 25°C (room temperature) for the reconstituted solution in the vial
- Up to 48 hours at 2–8°C (refrigerated) for the reconstituted solution in the vial
- 12 hours at 25°C or 24 hours at 2–8°C for the diluted solution in an infusion bag
From a microbiological standpoint, the product should ideally be used immediately after reconstitution. If not used immediately, storage times and conditions prior to administration are the responsibility of the healthcare professional and should normally not exceed 24 hours at 2–8°C unless reconstitution and dilution were performed under controlled and validated aseptic conditions.
What Does Cubicin Contain?
Each Cubicin vial contains 350 mg of daptomycin as the active substance. The only additional ingredient is sodium hydroxide (used for pH adjustment). The powder appears as a pale yellow to light brown cake or powder in a glass vial.
Cubicin contains only two components:
- Active substance: Daptomycin — 350 mg per vial
- Other ingredient: Sodium hydroxide (used to adjust the pH of the solution)
The product is supplied as a pale yellow to light brown lyophilized (freeze-dried) cake or powder in a glass vial. Before administration, it must be reconstituted with 0.9% sodium chloride solution to form a clear solution. Cubicin is available in packs containing 1 vial or 5 vials.
The marketing authorization holder is Merck Sharp & Dohme B.V., Waarderweg 39, 2031 BN Haarlem, Netherlands. Daptomycin is also available as generic formulations under several brand names, including Daptomycin Accordpharma, Daptomycin hameln, Daptomycin Advanz Pharma, Daptomycin Reddy, and Daptomycin Hospira.
Cubicin is physically and chemically compatible with the following agents when added to 0.9% sodium chloride infusion solutions: aztreonam, ceftazidime, ceftriaxone, gentamicin, fluconazole, levofloxacin, dopamine, heparin, and lidocaine. Cubicin is not compatible with glucose-containing solutions and must never be mixed with or infused through lines containing dextrose.
Frequently Asked Questions About Cubicin
Cubicin (daptomycin) is a cyclic lipopeptide antibiotic used to treat serious bacterial infections caused by Gram-positive organisms. It is approved for complicated skin and soft tissue infections (cSSTI) in adults and children aged 1–17 years, and for Staphylococcus aureus bacteremia and right-sided infective endocarditis in adults. It is particularly valuable for infections caused by methicillin-resistant Staphylococcus aureus (MRSA) and is administered intravenously in hospital settings.
No. Cubicin must not be used to treat pneumonia or any lung infection. Daptomycin is inactivated by pulmonary surfactant, a natural substance in the lungs that is essential for breathing. This inactivation renders daptomycin completely ineffective against respiratory pathogens. A clinical trial for community-acquired pneumonia demonstrated that daptomycin did not achieve adequate efficacy. Alternative antibiotics should be used for pulmonary infections.
Weekly blood tests during Cubicin therapy primarily measure creatine phosphokinase (CPK), an enzyme released from damaged muscle cells. Daptomycin can cause skeletal muscle toxicity, ranging from mild CPK elevation to potentially serious conditions such as myopathy and rhabdomyolysis (severe muscle breakdown). Early detection through regular CPK monitoring allows your doctor to discontinue the drug before serious muscle damage occurs. Your doctor may also monitor kidney function and other blood parameters during treatment.
Yes, there is a clinically significant interaction between Cubicin and statins. Both daptomycin and HMG-CoA reductase inhibitors (statins) can independently cause muscle toxicity, elevated CPK levels, and myopathy. When used together, the risk of additive or synergistic muscle damage increases. Most clinical guidelines and prescribing information recommend temporarily discontinuing statin therapy during daptomycin treatment. Always inform your doctor if you are taking any statin medication. The same caution applies to fibrates and ciclosporin.
Yes, Cubicin (daptomycin) is highly effective against methicillin-resistant Staphylococcus aureus (MRSA) and is one of the first-line recommended treatments for serious MRSA infections. International guidelines from the Infectious Diseases Society of America (IDSA) recommend daptomycin as a primary option for MRSA bacteremia and right-sided endocarditis. Its unique mechanism of action—disruption of the bacterial cell membrane—is fundamentally different from beta-lactam antibiotics, making cross-resistance very uncommon.
The duration of Cubicin treatment depends on the type and severity of infection. For complicated skin and soft tissue infections, a typical treatment course lasts 1 to 2 weeks. For bacteremia and right-sided endocarditis, treatment is usually longer, often 4 to 6 weeks or more, depending on clinical response and the presence of complications. Your doctor will determine the appropriate treatment length based on your individual clinical situation, blood culture results, and response to therapy.
References
- European Medicines Agency (EMA). Cubicin – Summary of Product Characteristics (SmPC). Updated 2025. Available at: ema.europa.eu/en/medicines/human/EPAR/cubicin
- U.S. Food and Drug Administration (FDA). Cubicin (daptomycin) – Prescribing Information. Available at: accessdata.fda.gov
- Liu C, Bayer A, Cosgrove SE, et al. Clinical Practice Guidelines by the Infectious Diseases Society of America (IDSA) for the Treatment of Methicillin-Resistant Staphylococcus aureus Infections in Adults and Children. Clin Infect Dis. 2011;52(3):e18–e55. doi:10.1093/cid/ciq146
- Gudiol F, Aguado JM, Almirante B, et al. Diagnosis and treatment of bacteremia and endocarditis caused by Staphylococcus aureus: a clinical guideline from the Spanish Society of Clinical Microbiology and Infectious Diseases (SEIMC). Enferm Infecc Microbiol Clin. 2015;33(9):625.e1–625.e23.
- Fowler VG Jr, Boucher HW, Corey GR, et al. Daptomycin versus standard therapy for bacteremia and endocarditis caused by Staphylococcus aureus. N Engl J Med. 2006;355(7):653–665. doi:10.1056/NEJMoa053783
- Arbeit RD, Maki D, Tally FP, Campanaro E, Eisenstein BI; Daptomycin 98-01 and 99-01 Investigators. The safety and efficacy of daptomycin for the treatment of complicated skin and skin-structure infections. Clin Infect Dis. 2004;38(12):1673–1681. doi:10.1086/420818
- World Health Organization (WHO). Model List of Essential Medicines, 23rd List, 2023. Geneva: WHO; 2023.
- Humphries RM, Pollett S, Sakoulas G. A current perspective on daptomycin for the clinical microbiologist. Clin Microbiol Rev. 2013;26(4):759–780. doi:10.1128/CMR.00030-13
- Gould IM, David MZ, Esposito S, et al. New insights into methicillin-resistant Staphylococcus aureus (MRSA) pathogenesis, treatment and resistance. Int J Antimicrob Agents. 2012;39(2):96–104.
About the Medical Editorial Team
Medical Writing
iMedic Medical Editorial Team
Specialists in infectious disease and clinical pharmacology. Content based on EMA SmPC, FDA prescribing information, and peer-reviewed literature following GRADE evidence framework.
Medical Review
iMedic Medical Review Board
Independent review by board-certified physicians. All claims verified against international guidelines (WHO, EMA, FDA, IDSA, ESCMID). Evidence Level 1A.