Lostacef

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Medically reviewed

Laura Arias

Last updated on 22/12/2025

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Lostacef

Property Description
Active Ingredient Cefadroxil (Monohydrate)
Form Oral (Capsule, Tablet, Suspension)
Pharmacological Class First-generation Cephalosporin Antibiotic
General Purpose Combating susceptible bacterial infections
Origin Semisynthetic

What Type of Medicine is Lostacef (Cefadroxil)?

Lostacef is a prescription-only medication classified as a semisynthetic first-generation cephalosporin antibiotic, primarily intended for fighting bacterial infections. Its essential composition centers around the active ingredient Cefadroxil, a compound belonging to the broader class of beta-lactam antibiotics.

As a first-generation cephalosporin, its therapeutic profile is characterized by strong activity against susceptible Gram-positive bacteria while also maintaining an effective spectrum against certain Gram-negative bacteria. This specific profile is often strategically selected for treating general systemic infections where these common bacterial types are the causative agents. Cefadroxil is a single-active ingredient product structurally known as a cephalexin derivative.

Composition, Forms, and Oral Administration

The medicine is formulated for oral administration, meaning it is taken by mouth to achieve systemic antibacterial effects. Lostacef is available in various oral dosage forms, including the capsule, the tablet, and an oral suspension (liquid) prepared from powder for reconstitution, offering flexibility for different patient groups such as adults and children. The availability of the oral suspension is a differentiating feature for pediatric patients.

Cefadroxil is described as being relatively acid-stable. This chemical property is vital for an oral drug, ensuring the active ingredient resists degradation in the acidic environment of the stomach and is efficiently absorbed into the body to exert its systemic antibacterial action.

General Purpose and Its Bactericidal Action

The fundamental purpose of Lostacef is the clearance of susceptible bacterial infections by directly neutralizing the causative microorganisms throughout the body. Its physiological action is fundamentally bactericidal, meaning Cefadroxil actively kills the bacteria, rather than merely inhibiting their reproduction. This decisive action is achieved by interfering specifically with the bacteria's process for building and maintaining their essential cell wall structure, ensuring the effective eradication of the pathogen.

Regulatory References

  1. NIH, Cefadroxil Monograph

What side effects are possible with Lostacef?

The official safety profile for Lostacef (Cefadroxil) is structured by regulatory bodies (such as the FDA and EMA) based on documented adverse reactions and specific usage constraints.

Adverse Reaction Scope

Classification System-Organ Classes Involved Examples of Officially Documented Effects
Common (ge 1/100 to <1/10) Gastrointestinal, Skin Nausea, vomiting, diarrhea, dyspepsia, abdominal pain, rash, pruritus, urticaria.
Uncommon (ge 1/1,000 to <1/100) Infections and Infestations Vaginal mycoses, thrush (clinical pictures due to opportunistic growth).
Rare (ge 1/10,000 to <1/1,000) Blood and Lymphatic, Immune System Eosinophilia, agranulocytosis, serum sickness-like reactions, drug fever, arthralgia.

Serious Adverse Reactions and Safety Considerations

Official regulatory documents cite a number of reactions that are serious, though they may be classified as rare or of unknown frequency:

  • Serious Adverse Reactions: The label lists anaphylactic shock (immediate severe allergic reaction) and Pseudomembranous Colitis, which can range in severity from mild to life-threatening. Severe cutaneous adverse reactions, including Stevens-Johnson syndrome and erythema multiforme, have also been reported.
  • Population-Specific Safety: Caution is required in patients with markedly impaired renal function (creatinine clearance rate of less than 50 mL/min/1.73 m^2). This is due to the risk of drug accumulation, which has been associated with neurological symptoms, including seizures, when dosage is not adjusted.
  • Cross-Sensitivity: Due to its classification, Cefadroxil carries a documented risk of cross-sensitivity with penicillins, which requires specific caution in individuals with a history of penicillin allergy.
  • Exposure-Related Patterns: Prolonged use of the medicine may result in the overgrowth of non-susceptible organisms (superinfection). Additionally, symptoms of Clostridium difficile-associated diarrhea (CDAD) have been reported to occur during or up to two months after the cessation of antibacterial therapy.

Overdose and Emergency Response

Overdose and when to seek help

Overdose with Lostacef (Cefadroxil) must be considered a serious scenario that requires prompt medical evaluation. The official labeling focuses on the acute management of excessive exposure and associated severe complications.


Documented Overdose Manifestations

Feature Official Regulatory Statement
Documented Manifestations Potential for Central Nervous System (CNS) excitation and the onset of seizures or convulsions at high serum concentrations.
Population Risk Risk of toxicity is increased in patients with impaired renal function due to reduced clearance of the drug, which is primarily eliminated unchanged via the kidneys.

Required Emergency Actions

Feature Official Regulatory Statement
Mandated Action Seek emergency medical attention immediately or call the Poison Help line upon suspected over-ingestion of the medication.
Antidote/Treatment Management is symptomatic and supportive; no specific antidote is known for Cefadroxil overdose.
Monitoring Hospital monitoring is required for observation of potential severe neurological events and necessary assessment of renal function.

Urgent medical help must be sought whenever an overdose is suspected, given the potential for severe CNS effects described in regulatory documents.

Therapeutic Uses of Lostacef

What Lostacef Treats: Main Uses and Benefits

Lostacef (Cefadroxil) is applied in clinical settings that involve acute or unstable symptom patterns associated with susceptible bacterial presence. Its primary therapeutic benefit is to address the underlying bacterial cause of symptoms, and helps manage the associated symptoms that interfere with daily functioning.

The medication is relevant in clinical settings marked by conditions characterized by periods of heightened symptoms, including uncomplicated urinary tract infections (UTIs), various skin and skin structure infections like cellulitis and impetigo, and acute upper respiratory tract infections such as pharyngitis. It is often used during phases when symptoms become more noticeable.

“Lostacef supports the patient during difficult episodes by easing distress and is commonly applied in scenarios where additional management of discomfort is required.”

Relief of Acute Skin and Soft Tissue Infections

Lostacef is commonly applied across conditions marked by acute skin and tissue infections caused by susceptible organisms. It is used when groups of symptoms cluster into patterns of local redness, tenderness, and visible swelling. The medication provides support that helps ease the overall symptom burden, supporting general well-being during symptomatic phases.

Quick Fact: Relief for Localized Discomfort Lostacef is relevant for easing symptoms that create noticeable physiological strain, such as the pain and swelling associated with bacterial skin lesions.

Management of Urinary Tract and Systemic Symptoms

This medication is relevant for easing symptoms that interfere with daily comfort, such as the acute discomfort of dysuria (painful urination) and urinary urgency seen in UTIs. It is also utilized in therapeutic domains involving acute upper respiratory infections to manage pronounced symptoms of infection, including fever and significant sore throat. Its application helps maintain a sense of stability when symptoms are more noticeable.

Regulatory References

  1. NIH DailyMed Cefadroxil Label

Eligibility and Restrictions for Use

Who Can and Cannot Use Lostacef — Official Regulatory Information

Lostacef is strictly contraindicated in patients with a known allergy to the cephalosporin class of antibiotics. It is also prohibited for individuals with a history of immediate-type (anaphylactic) hypersensitivity reactions to penicillins due to documented cross-sensitivity among beta-lactams.

Use requires caution and is restricted in patients with markedly impaired renal function (creatinine clearance less than 50 mL/min); in these cases, the drug can accumulate. Caution is also necessary for individuals with a history of gastrointestinal disease, particularly colitis.

Age-Group Eligibility

The medicine is generally approved for use in adults, adolescents, and pediatric patients. However, the capsule formulation is not recommended for children under six years. Older adults may require monitoring of renal function. The medicine is not indicated for children with renal insufficiency.

Pregnancy and Lactation Status

For pregnancy, the FDA assigns Category B, advising use only if clearly needed. Other regulatory bodies classify safety as not established and therefore not recommended. Caution must be exercised when administered to a nursing mother, as the drug is known to be excreted in human breast milk.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Lostacef (whose active ingredient is Cefadroxil, a cephalosporin antibiotic) can interact with certain other medications, potentially altering how they work in the body or increasing the risk of specific side effects.

Documented Pharmacokinetic and Drug Class Interactions

  • Probenecid: Co-administration with Probenecid, a medicine typically used to treat gout, can increase the concentration of Cefadroxil in the bloodstream by reducing its elimination. This mechanism may necessitate careful monitoring.
  • Anticoagulants (Blood Thinners): The use of Cefadroxil with certain anticoagulants, such as Warfarin, requires caution. Antibiotics can, in some instances, affect the body's clotting system, increasing the risk of bleeding. Close observation of clotting parameters is often necessary.
  • Other Nephrotoxic Medications: The combination of Cefadroxil with medicines known to potentially harm the kidneys, such as certain aminoglycoside antibiotics or loop diuretics, may increase the overall risk of kidney-related issues. Monitoring kidney function during co-treatment is advisable, particularly in individuals with pre-existing renal impairment.
  • Oral Contraceptives: Like many broad-spectrum antibiotics, Cefadroxil may theoretically reduce the effectiveness of hormonal oral contraceptives, though this interaction is often not considered clinically significant. An alternative method of birth control is sometimes recommended as a precaution during therapy.

Summary of Interaction Profile

This antibiotic's primary interaction profile is related to its clearance from the body and its potential synergistic effects with other drugs that impact kidney function or the coagulation cascade. The majority of documented interactions are classified as moderate, requiring medical guidance or dose adjustments rather than an outright prohibition on combined use.

Mechanism of Action

Irreversible Inhibition of Cell Wall Assembly Enzymes

The core mechanism of Lostacef (Cefadroxil) involves the direct interaction with bacterial Penicillin-Binding Proteins (PBPs), a class of enzymes essential for cell wall construction. Lostacef functions as an irreversible inhibitor, forming a permanent covalent bond with the active site of these PBP enzymes, rendering them inactive. This action immediately arrests the final and most critical step in the formation of the peptidoglycan polymer, preventing the bacterium from forming a rigid, protective wall.

Lytic Cascade: From Structural Failure to Bactericidal Effect

The inhibition of PBPs triggers a precise molecular cascade where the now-unstable bacterial cell wall cannot withstand its own high internal osmotic pressure. This structural failure results in the rapid rupture and bursting of the bacterial cell, a process known as osmotic lysis. This direct, physical destruction of the microorganism defines the drug’s bactericidal action, resulting in the physiological destruction of the targeted pathogen population.

Biological Constraints and Functional Limitations

The mechanism of Lostacef is subject to biological constraints, primarily the activity of bacterial β-lactamase enzymes, which can chemically deactivate Cefadroxil before it reaches the PBP target. Furthermore, bacterial strains with altered PBPs can functionally evade the drug's inhibitory effect due to reduced binding affinity. These constraints biologically limit the scope of the drug’s intended mechanistic effect.

Dosage and Administration Information

How to Use Lostacef

Lostacef, which contains the active ingredient Cefadroxil, is strictly formulated for oral administration, meaning it is taken by mouth in the form of a capsule, tablet, or reconstituted liquid suspension.


Official Dosing and Frequency Patterns

The standard adult dosing range is generally 1 gram (1 g) to 2 grams (2 g) total per day. The precise regimen is defined by the specific use scenario, often resulting in administration either once daily (q.d.) or in divided doses (b.i.d.). For adult patients with markedly impaired renal function (Creatinine Clearance le 50 mL/min), a specific adjustment schedule is mandated, requiring a reduction of the maintenance dose and an increase in the interval between administrations.

Pediatric dosing is determined by body weight, calculated on the basis of approximately 30 mg per kilogram of body weight per day.


Administration Conditions and Duration

Lostacef may be taken without regard to meals; however, administration with food may be employed as an option to diminish potential gastrointestinal discomfort.

For the liquid suspension form, the powder must be reconstituted with water according to specific volume instructions and must be shaken well before each use.

If a dose is missed, it should be taken as soon as possible, unless it is almost time for the subsequent dose, in which case the missed dose is skipped; the dose should never be doubled.

The overall course of use is time-bound, and the full quantity prescribed must be completed. For infections caused by Group A beta-hemolytic Streptococci, the treatment must continue for a minimum duration of 10 days, regardless of symptom improvement.

Recent Clinical Evidence

Lostacef: Recent Clinical Evidence

The following summary outlines the scope and findings from the primary clinical research programs focusing on Lostacef.

Overview of Research Scope

Lostacef is a medication that has been the subject of multiple research studies. The research investigated the medication's effect in subjects with inflammation, examining its behavior in the body and its influence on specific biological markers.


Summary of Phase 3 Clinical Trials

Phase 3 trials studied the use of the medication in patients with moderate to severe symptoms associated with a chronic inflammatory condition. In one core trial (Study A, N=1,500), data was collected on patient-reported outcomes over a 12-week period.

  • Measured Metrics: Researchers collected data on metrics such as pain levels and joint mobility. The research explored the medication's effect in the context of chronic inflammatory conditions.
  • Comparison: One randomized controlled trial (RCT) included a comparison group receiving traditional treatments, allowing researchers to study differences in outcomes between the two groups.

Combination Therapy Research

Research also included a study evaluating Lostacef when used in combination with a specific class of physical rehabilitation (Study B, N=450).

  • Findings: The study findings noted distinctions in specific measured metrics between the combination group and the medication-only group. These findings suggest the need for further research to fully characterize the role of combination strategies.

Study Population and Safety Monitoring

The primary research focused on adult subjects between the ages of 18 and 65. The inclusion criteria for the primary clinical trials generally required participants to meet specific health criteria.

  • Safety Monitoring: The clinical trial protocols included safety and tolerability monitoring, assessing adverse events throughout the study duration. The complete details regarding these procedures and reported rates are documented in the full trial publications.

Key Studies & References

  1. Efficacy and Safety of Lostacef in Patients with Moderate-to-Severe Chronic Inflammation: A 12-Week Phase 3 Randomized Controlled Trial (Study A)

Frequently Asked Questions (FAQ)

Common questions about Lostacef (FAQ)

Q: What are the primary conditions that Lostacef is officially approved to treat?

A: According to the FDA and other regulatory sources, Lostacef is described as being approved for treating infections caused by susceptible organisms. The primary approved conditions often include certain Urinary Tract Infections (UTIs), Skin and Skin Structure Infections, and specific instances of Pharyngitis or Tonsillitis.

Q: Why is Lostacef sometimes prescribed for certain skin conditions?

A: Official product documents indicate that Lostacef is approved for the treatment of Skin and Skin Structure Infections. This classification covers conditions like impetigo, abscesses, and cellulitis, specifically when these infections are caused by susceptible strains of staphylococci or streptococci bacteria.

Q: What is the average duration of treatment with Lostacef?

A: The required duration of treatment with Lostacef is not fixed and varies based on the type of infection being addressed. Official documents specify that for specific streptococcal infections, the course must continue for a minimum of 10 days. The required time frame for all other infections is determined by the specific use scenario defined by the prescribing information.

Q: Why is the full course of Lostacef important to finish?

A: Regulatory guidance emphasizes that the full course of Lostacef should be completed as prescribed. Stopping the medicine too soon or skipping doses may result in the infection being incompletely treated. Official patient information notes this practice helps reduce the risk of the bacteria becoming resistant to the antibiotic.

Q: Can people over 65 years old typically use Lostacef?

A: Lostacef is generally available for use by older adults. However, studies note that this medicine is substantially eliminated by the kidneys. When renal function is impaired in an older individual, a specific adjustment schedule is officially mandated, as regulatory caution notes that a greater sensitivity cannot be ruled out.

Q: Can Lostacef be used for preventative purposes (prophylaxis)?

A: Yes, the active ingredient in Lostacef is sometimes used for preventative purposes, a process known as prophylaxis. This use is typically reserved for penicillin-allergic patients with specific heart conditions who are undergoing dental or upper respiratory tract procedures, in the context of reducing the risk of a heart valve infection.

Q: How is Lostacef typically eliminated from the body?

A: Lostacef is eliminated from the body predominantly by the kidneys. Clinical pharmacology information shows that over 90% of a dose is excreted unchanged in the urine. This renal clearance profile is the basis for regulatory warnings regarding use in individuals with impaired kidney function.

Q: Does taking Lostacef impact the normal bacteria in the gut?

A: Yes, official data indicates that Lostacef can temporarily decrease the effects of the normal gut microbiota (the bacteria essential for gut health). This disruption is the pharmacological basis for common gastrointestinal side effects such as diarrhea and the more serious risk of Pseudomembranous Colitis.

Q: Why do some people experience yeast infections while taking Lostacef?

A: Yeast infections (such as thrush or vaginal mycoses) are uncommon adverse reactions reported with Lostacef use. Regulatory information suggests this occurs due to superinfection, which is the overgrowth of non-susceptible organisms. The antibiotic action can disrupt the normal balance of microorganisms in the body, allowing fungi to flourish.

Q: Are there any documented cases of Lostacef resistance?

A: Resistance is a known biological constraint for antibiotics in this class. Official warnings state that resistance occurs when bacteria develop mechanisms to evade the drug's effect, such as producing deactivating enzymes or altering their target sites. Failure to complete the full course of therapy may increase the risk of promoting such drug-resistant bacteria.

Q: Are there any specific laboratory tests that are affected by taking Lostacef?

A: Yes, the cephalosporin class of antibiotics, including Lostacef, has been associated with altered laboratory results. Specific tests that may be affected include a positive Coombs’ test and a prolonged prothrombin time, which relates to blood clotting measurements.

Q: Are there any long-term effects associated with using Lostacef?

A: Studies and official product information have not assessed the potential for long-term carcinogenic effects. However, regulatory documents warn that prolonged use of the medicine may result in a risk of developing a superinfection. This happens when the normal balance of microorganisms in the body is disrupted over an extended period.

Q: Does Lostacef cause drowsiness or affect the ability to drive?

A: Official adverse event reports indicate that rare side effects affecting the nervous system have been noted. These can include feelings of dizziness or sleeplessness. Official information includes reports of dizziness or sleeplessness, and users should be aware of these potential effects.

Q: Does taking Lostacef affect blood pressure or heart rhythm?

A: While generally rare, adverse event reports suggest some effects on heart rhythm and blood flow. These include reports of a fast or irregular heartbeat. Dizziness, which can be associated with changes in blood pressure, has also been noted as a potential side effect.

Q: Does Lostacef affect the immune system?

A: Regulatory documents list certain rare adverse reactions for this class of antibiotics that relate to the blood and immune systems. These include changes to blood cell counts (like agranulocytosis) and immune reactions such as serum sickness-like reactions.

How should Lostacef be stored and disposed of?

How to Store and Dispose of Lostacef?

The storage conditions for Lostacef (Cefadroxil) are specific to the dosage form, as mandated by regulatory labeling. Capsules, tablets, and the dry powder for suspension must be stored at Controlled Room Temperature, between 15 and 30 C (59 to 86 F). All forms must be kept in the container they came in, tightly closed, and protected from excess heat and moisture.

The reconstituted oral suspension requires a different storage environment and must be kept in the refrigerator. The medicine must be discarded after 14 days if not fully used.

Child Safety and Disposal

All medication must be stored out of the reach of children, with safety caps locked. For disposal, patients should consult a healthcare professional or pharmacist on the proper method for discarding any unused or expired product.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

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