Iclaprim
Pronunciation: (eye-CLA-prim).
- Generic name
- iclaprim
- Brand names
- Iclaprim, Primicin, Iclaprim-Plus
- Drug class
- Antibiotic (Dihydrofolate Reductase Inhibitor)
Availability and supply rules vary by country
Trade names by country:
Australia: · Full directory
What iclaprim is and how it works
Uses, formulations, monitoring, and supply rules can differ by patient, product, and country. Follow the exact local product information and professional advice.
Mechanism of action: how iclaprim works
Iclaprim is a selective dihydrofolate reductase (DHFR) inhibitor. It blocks the bacterial DHFR enzyme, preventing the reduction of dihydrofolic acid to tetrahydrofolic acid, a critical step in bacterial DNA, RNA, and protein synthesis. This inhibition leads to bactericidal activity against susceptible Gram-positive organisms, including MRSA and Streptococcus pneumoniae.
What iclaprim is used for
Acute bacterial skin and skin structure infections (ABSSSI) — studied in clinical trials, NOT an approved indication
CORRECTED: iclaprim was studied for this indication in the Phase 3 REVIVE-1 and REVIVE-2 trials versus vancomycin, but the FDA declined to approve it (Complete Response Letter, 2019) due to (2)
Hospital-acquired bacterial pneumonia (HABP) / ventilator-associated bacterial pneumonia (VABP) — studied in earlier-phase trials, NOT an approved indication
Recorded in the clinician database as a studied use; not an FDA-approved indication. (2)
Before taking iclaprim
Do not take / not appropriate for
- Contraindicated in patients with known hypersensitivity to iclaprim or other DHFR inhibitors, and in those with severe hepatic impairment. (Contraindication)
Tell your clinician about
(2)How to take iclaprim
- General Instructions: Iclaprim is administered by a healthcare professional as an intravenous infusion, usually in a hospital setting. Do not attempt to self-administer.. Adult Dosing: The typical adult dose is 80 mg administered intravenously every 12 hours for 5–7 days, depending on the infection and clinical response.. Pediatric Dosing: Safety and efficacy in children under 18 years have not been established. Use in pediatric patients is not routinely recommended.. Administration: Given as a slow intravenous infusion over 2 hours. Follow all instructions from your healthcare provider.. When To Stop: Complete the full prescribed course. Stop only if instructed by your doctor due to side effects or allergic reaction.. Storage: Store vials at room temperature, away from moisture and heat. Prepared infusions should be used promptly or stored as directed by hospital protocols.
- This page does not provide a dose calculator. Dosing must follow the prescriber, pharmacist, or product label.
Procedures and treatment changes
Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (2)
Missed dose
If you miss a dose, contact your healthcare provider immediately. Do not double up on doses. Hospital staff will ensure proper dosing schedule.
Overdose
In case of overdose, seek emergency medical attention. Symptoms may include severe nausea, vomiting, confusion, or signs of liver toxicity. Supportive care and monitoring are essential as there is no specific antidote. (2)
Side effects
Side effects and their urgency vary; report severe, persistent, or concerning symptoms to a healthcare professional.
Nausea
Incidence: Reported in the clinician-authored database; frequency not established
Diarrhea
Incidence: Reported in the clinician-authored database; frequency not established
Vomiting
Incidence: Reported in the clinician-authored database; frequency not established
Headache
Incidence: Reported in the clinician-authored database; frequency not established
Rash
Incidence: Reported in the clinician-authored database; frequency not established
Anemia
Incidence: Reported in the clinician-authored database; frequency not established
Thrombocytopenia
Incidence: Reported in the clinician-authored database; frequency not established
Signs of liver problems: yellowing of the skin/eyes, dark urine, unusual fatigue, or right upper abdominal pain
(1)Signs of an allergic reaction: rash, hives, swelling of the face/lips/tongue/throat, or difficulty breathing
(1)Unusual bleeding or bruising, or signs of anemia (fatigue, pale skin)
(1)Serious warnings
MOST IMPORTANT WARNING — serious
Symptoms: MOST IMPORTANT WARNING: Iclaprim is NOT an FDA-approved medicine and is not currently commercially available for prescription anywhere verified. The FDA declined to approve it in 2019 specifically because of unresolved questions about liver toxicity risk raised in its clinical trial data. Anyone encountering this drug name would only do so through participation in a clinical trial, not a standard prescription — always verify the current regulatory and trial status with a clinician or the trial sponsor before assuming this is an available treatment.
Action: Follow the urgency stated and seek prompt or emergency care when indicated. (2)
Serious allergic reactions may occur — serious
Symptoms: Serious allergic reactions may occur. May cause liver toxicity; monitor liver function. Not recommended in severe renal or hepatic impairment. May interact with other medications affecting folate metabolism. Use in pregnancy and breastfeeding only if clearly needed.
Action: Follow the urgency stated and seek prompt or emergency care when indicated. (2)
Contraindications recorded in the clinician database — serious
Symptoms: Contraindications recorded in the clinician database: Contraindicated in patients with known hypersensitivity to iclaprim or other DHFR inhibitors, and in those with severe hepatic impairment. Use with caution in patients with moderate renal or hepatic dysfunction. Monitor for signs of hypersensitivity, hematologic changes, and liver toxicity.
Action: Follow the urgency stated and seek prompt or emergency care when indicated. (2)
Interactions
| Medicine or test | Effect | Action |
|---|---|---|
| Recorded interactions | Iclaprim may interact with drugs that affect folate metabolism (such as methotrexate), other antibiotics, and medications that are hepatotoxic. Always inform your healthcare provider of all medicines you are taking. | (1) |
Pregnancy, breastfeeding, kidney/liver function, age
Pregnancy
Not established; no published data were identified. Since iclaprim is not an approved medicine, this would only be relevant to someone considering clinical trial participation, which has its own separate, trial-specific safety review and consent process. (2)
Breastfeeding
Not established; no published data were identified, for the same reason as pregnancy above. (2)
Children
Frequency: Not applicable.. Weight Based: Not recommended for pediatric use.. Max Daily Dose: Not applicable.. Max Single Dose: Not applicable.. Age Restrictions: Safety not established in children. (2)
Renal_impairment
The clinician database records general caution in renal/hepatic impairment and contraindication in severe hepatic impairment; no published, approved-label-level renal or hepatic dose-adjustment regimen exists because iclaprim has not been approved. (2)
Hepatic_impairment
The clinician database records general caution in renal/hepatic impairment and contraindication in severe hepatic impairment; no published, approved-label-level renal or hepatic dose-adjustment regimen exists because iclaprim has not been approved. (2)
Monitoring
(2)Storage
The clinician database records storage at room temperature for unopened vials, away from moisture and heat, with prepared infusions used promptly per institutional protocol; no official approved-product storage label exists because iclaprim has not been approved.
Professional information
Clinician-facing context only. This section does not replace current product labeling.
General
Indication: Acute bacterial skin and skin structure infections (ABSSSI)
Dose summary: The Phase 3 REVIVE-1/REVIVE-2 trials used a fixed dose of 80 mg IV every 12 hours for 5-14 days. -- CORRECTS an internal inconsistency in the clinician database: its 'Adult dosing' field said 10 mg, while its 'Administration' field said 80 mg; published clinical trial data confirm 80 mg is correct. This dosing was used in trials only — there is no approved commercial dosing, since iclaprim is not an approved medicine.
Renal context: Not established; iclaprim is not an approved medicine and no official renal-dosing guidance has been published. (2)
Frequently asked questions
What infections does iclaprim treat?
Iclaprim is NOT an FDA-approved medicine — it is an investigational antibiotic. In clinical trials, it was studied for complicated skin and soft tissue infections and hospital-acquired pneumonia caused by Gram-positive bacteria, including MRSA, but the FDA declined to approve it in 2019 due to
How is iclaprim given?
In the clinical trials where it was studied, iclaprim was given as an intravenous infusion by a healthcare professional in a hospital setting. It is not currently available as a prescribed treatment outside of a clinical trial.
Can Iclaprim be used in children?
The safety and effectiveness of iclaprim in children under 18 years have not been established, and its use is not routinely recommended in pediatric patients.
What should I do if I experience side effects?
Report any side effects to your healthcare provider. Seek immediate medical attention for severe reactions such as difficulty breathing, severe rash, or jaundice.
Can I take iclaprim if I am pregnant or breastfeeding?
Iclaprim should be used during pregnancy or breastfeeding only if clearly needed and prescribed by your doctor, as safety data is limited.
Are there any foods or medicines I should avoid while taking iclaprim?
Avoid alcohol and inform your doctor about all other medications you are taking, especially those affecting folate metabolism or liver function.
What happens if I miss a dose?
If you miss a dose, contact your healthcare provider immediately. Do not attempt to double the next dose.
What happens if I take too much Iclaprim?
Taking too much Iclaprim can lead to an overdose, potentially causing exacerbated side effects such as nausea, vomiting, or more severe reactions. If you suspect an overdose, it is crucial to seek immediate emergency medical attention. Do not attempt to self-treat an overdose, as professional medical intervention is necessary to manage potential complications.
Can I drink alcohol while taking Iclaprim?
While there isn't a direct contraindication for alcohol consumption with Iclaprim, it's generally advisable to limit or avoid alcohol when taking antibiotics. Alcohol can potentially worsen common side effects like nausea or dizziness, and may also interfere with your body's ability to fight off infection. Always consult your healthcare provider for personalized advice regarding alcohol and medication.
Is Iclaprim safe during pregnancy?
The safety of Iclaprim during pregnancy falls under a specific pregnancy category, which indicates the level of risk. It is essential to consult your doctor if you are pregnant, planning to become pregnant, or breastfeeding before taking Iclaprim. Your healthcare provider can assess the potential benefits against any risks to both you and your baby, and recommend the most appropriate course of action.
What is the mechanism of action of iclaprim?
Iclaprim is a selective dihydrofolate reductase (DHFR) inhibitor. It blocks the bacterial DHFR enzyme, preventing the reduction of dihydrofolic acid to tetrahydrofolic acid, a critical step in bacterial DNA, RNA, and protein synthesis. This inhibition leads to bactericidal activity against susceptible Gram-positive organisms, including MRSA and Streptococcus pneumoniae.
What is the generic name of Iclaprim?
The generic name is iclaprim. It is sold under brand names including Iclaprim, Primicin, Iclaprim-Plus.
What class of drug is iclaprim?
Iclaprim is classed as: Antibiotic (Dihydrofolate Reductase Inhibitor).
References
- Iclaprim clinician-authored medicine recordMedGuideGlobal (internal clinician-authored record) · null · accessed 2026-08-06 · source 1
- FDA issues Complete Response Letter for iclaprim NDA; Phase 3 REVIVE-1 and REVIVE-2 trial resultsU.S. Food and Drug Administration (Complete Response Letter) and ContagionLive reporting · United States · dated 2019 · accessed 2026-08-06 · source 2
Brand names by country
Single-ingredient iclaprim names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.