Why Pneumonia and Skin Infections Need Good Options

Two Common Infections

Community-acquired bacterial pneumonia brings many adults to the hospital each year, and acute bacterial skin and skin structure infections such as abscesses, deep cellulitis, and wound infections are among the most frequent reasons for antibiotic prescriptions. Both can be treated as outpatients in mild cases, but moderate and severe infections often start with IV therapy.

The Problem of Resistance

Resistance to common drugs, including macrolides, some fluoroquinolones, and older tetracyclines, has narrowed choices for many patients. Clinicians have wanted options that work against common pathogens, cover atypical organisms, and allow a smooth transition from hospital to home.

Why Transitions Matter

Every extra day in hospital adds cost and risk. A drug that can be given by IV and then continued as a pill, at the same dose and schedule, can shorten hospital stays when a patient is improving.

Key Takeaways

• Nuzyra (omadacycline) received FDA approval on October 2, 2018, for adults with CABP and ABSSSI caused by susceptible organisms.
• It is a modernized tetracycline in the aminomethylcycline subclass, available as IV and oral forms dosed once daily.
• The OPTIC trial compared it with moxifloxacin for CABP, and the OASIS-1 and OASIS-2 trials compared it with linezolid for ABSSSI.
• The label warns about permanent tooth discoloration and enamel hypoplasia, bone growth inhibition, hypersensitivity, and C. difficile infection.
• Use in children under 8 years of age is not recommended, and pregnancy and breastfeeding need careful risk-benefit discussion.
• The label directs use only for infections proven or strongly suspected to be caused by susceptible bacteria, to limit resistance.

What Is Nuzyra

Brand and Generic Names

Nuzyra is the brand name for omadacycline, developed by Paratek Pharmaceuticals. It is supplied as lyophilized powder for IV infusion and as oral tablets. Both forms use the same once-daily dosing approach.

Drug Class

Omadacycline belongs to the tetracycline class of antibiotics, which inhibit bacterial protein synthesis. It is in the aminomethylcycline subclass, a chemically modified tetracycline. Its label describes it as a modernized version of the older tetracyclines.

Why the Formulations Matter

Having both IV and oral forms within a single drug means a patient can start therapy in hospital and continue at home without switching to a different antibiotic.

FDA Approval: October 2, 2018

The Approval Decision

The FDA approved Nuzyra on October 2, 2018, for adults with CABP and ABSSSI caused by susceptible microorganisms. The agency's announcement noted that the drug should be used only when infections are proven or strongly suspected to be caused by susceptible bacteria, a standard stewardship statement.

Advisory Committee

The FDA's Antimicrobial Drugs Advisory Committee recommended approval in August 2018, before the final decision.

Postmarketing Commitments

As part of approval, the sponsor agreed to conduct further studies in CABP and in pediatric populations. Information from those studies may change labeling over time, so check the current prescribing information.

The Tetracycline Family and Why This Version Is Different

A Familiar Class

Tetracyclines such as doxycycline and minocycline have been used for more than half a century. They share a core structure and a set of class warnings, including effects on developing teeth and bones and the risk of C. difficile infection.

What Changed

Omadacycline has added chemical groups that help it overcome two common resistance mechanisms in tetracycline-resistant bacteria: efflux pumps that push the drug out of the cell, and ribosomal protection proteins that block its target. The label describes it as designed to overcome tetracycline resistance.

Not Interchangeable

Omadacycline is a separate medicine with its own labeling. It is not a substitute for doxycycline or minocycline in other conditions, and its approved uses are limited to CABP and ABSSSI.

How Omadacycline Works

Protein Synthesis Inhibition

Omadacycline binds to the bacterial 30S ribosomal subunit and blocks the addition of new amino acids to growing proteins. Without functional proteins, the bacteria cannot grow and replicate. Tetracyclines are generally considered bacteriostatic, meaning they inhibit growth rather than directly killing bacteria, and the immune system plays a role in clearing the infection.

Activity and Tissue Levels

Omadacycline reaches lung tissue and skin at concentrations relevant to the approved infections. Pharmacokinetic studies show that it is excreted partly unchanged in urine and partly through other routes, which is why dosing is adjusted for individual patients by clinicians.

Why Dosing Schedule Matters

Once-daily dosing is a practical benefit. Maintaining steady drug levels with a consistent schedule supports the antibacterial effect over the course of treatment.

Approved Uses

Community-Acquired Bacterial Pneumonia

Nuzyra is approved for adults with CABP caused by susceptible organisms. The label lists common pathogens, including Streptococcus pneumoniae, Haemophilus influenzae, Legionella pneumophila, Mycoplasma pneumoniae, and Chlamydophila pneumoniae. Treatment decisions depend on severity, local resistance, and patient factors.

Acute Bacterial Skin and Skin Structure Infections

Nuzyra is also approved for adults with ABSSSI caused by susceptible organisms. Covered pathogens include Staphylococcus aureus (both methicillin-susceptible and methicillin-resistant isolates), Streptococcus pyogenes, and several enterococci and gram-negative organisms named in the label.

Not Approved For

Omadacycline is not approved for uncomplicated urinary tract infections in these labeled pages, bloodstream infections, or conditions unrelated to CABP and ABSSSI. Off-label use is a clinical decision that carries its own considerations.

The OPTIC Trial: Pneumonia

Design

The OPTIC trial was a multinational, randomized, double-blind, double-dummy noninferiority study. Adults with CABP were randomized to omadacycline or moxifloxacin, a respiratory fluoroquinolone. Double-dummy design means both groups received matching active drug and placebo, which helps keep the comparison unbiased.

Why Moxifloxacin Was the Comparator

Moxifloxacin is a widely used standard for CABP that covers typical and atypical organisms. Comparing against it asks whether omadacycline is about as effective as an established option.

Primary Question

The primary question was whether omadacycline was noninferior to moxifloxacin in clinical response at an early assessment. The FDA considered the results sufficient for approval in CABP.

The OASIS Trials: Skin Infections

Design

OASIS-1 and OASIS-2 were two multicenter, multinational, double-blind, double-dummy trials in adults with ABSSSI. Patients received omadacycline or linezolid, another standard IV and oral antibiotic for skin infections.

Two Dosing Approaches

OASIS-1 used an IV-to-oral approach, starting with IV therapy and continuing with tablets. OASIS-2 used an oral loading dose. These two designs tested how the drug works in different practical settings.

Pooled Results

The pooled OASIS analysis found omadacycline noninferior to linezolid for early clinical response in ABSSSI. This is the main efficacy basis for the skin indication.

Trial Results Explained

Noninferiority Explained

All three pivotal trials were noninferiority studies. They show that omadacycline performed comparably to established comparators within a pre-set margin. They do not prove omadacycline is more effective.

Safety Signals

In the pooled ABSSSI trials, serious adverse reactions occurred in a small percentage of patients, and discontinuations due to adverse reactions were similar across groups. In the OPTIC pneumonia trial, the serious adverse event rate was similar to moxifloxacin. There was a mortality imbalance in CABP, discussed below.

Context for Patients

Clinical trials enroll selected patients and may not reflect every real-world situation. Your clinician weighs trial evidence alongside your infection, health history, and local resistance patterns.

Which Bacteria It Targets

Pneumonia Pathogens

The label for CABP lists organisms including Streptococcus pneumoniae, Haemophilus influenzae, Klebsiella pneumoniae, Legionella pneumophila, Mycoplasma pneumoniae, and Chlamydophila pneumoniae. Atypical coverage is one reason clinicians consider it for pneumonia.

Skin Infection Pathogens

For ABSSSI, the label lists Staphylococcus aureus, including MRSA, Streptococcus pyogenes, Streptococcus anginosus group, Enterococcus faecalis, and some gram-negative organisms. Susceptibility testing should guide therapy whenever it is available.

Not Universal

No antibiotic covers every organism. Some resistant gram-negative bacteria and certain pathogens are not covered. Culture results and susceptibility testing help avoid mismatched therapy.

IV-to-Oral Treatment

The Practical Advantage

Because the IV and oral forms share the same drug and schedule, a patient who is improving in hospital can switch to tablets at home without changing antibiotics. This can support earlier discharge when the care team judges it safe.

When Switching Makes Sense

The care team decides when to switch based on clinical stability, fever resolution, the ability to swallow, and the infection's response. Not every patient is a candidate.

Continuity

Finish the full course on the schedule your team sets. Stopping early because you feel better can allow the infection to return.

Dosing, Food, and Duration

General Approach

Nuzyra is given once daily. The labeled regimens for CABP and ABSSSI differ, and the label includes loading-dose information for oral therapy. Follow the current prescribing information and your care team's instructions, because doses are specific to the form and indication.

Duration

Labeled treatment for CABP and ABSSSI generally runs from 7 to 14 days. The exact length depends on the infection, severity, and response.

Taking Tablets

The label gives specific instructions about taking tablets with water and about fasting around the dose. Some tetracyclines are less well absorbed when taken with food, dairy, or minerals such as calcium, iron, magnesium, or aluminum. Ask your pharmacist about separating doses from antacids, supplements, and dairy.

Missed Doses

If you miss a tablet, take it when you remember unless it is almost time for the next dose. Do not double up.

Tooth Discoloration Warning

What the Label Says

The label warns that using Nuzyra during tooth development can cause permanent discoloration of the teeth (yellow-gray-brown) and enamel hypoplasia. Tooth development covers the last half of pregnancy, infancy, and childhood up to age 8.

Why This Matters

The effect on teeth is permanent. It is one reason the drug is not recommended for children under 8 and why pregnancy is a major consideration.

Other Tetracyclines

Doxycycline, minocycline, and other tetracyclines carry similar tooth warnings. Clinicians weigh these risks when choosing any drug in the class.

Bone Growth and Pregnancy Warnings

Inhibition of Bone Growth

Tetracyclines can reversibly inhibit bone growth when used during the second and third trimesters of pregnancy and in young children. The label advises patients about this risk.

Fetal Harm

Omadacycline may cause embryo-fetal harm. Animal studies showed effects on fetal weight and embryo loss at certain doses. Pregnant patients should discuss the risks and alternatives with their obstetric and infectious disease teams.

Contraception

Women who could become pregnant should talk to their clinician about pregnancy testing and contraception before starting therapy.

Children and Breastfeeding

Children Under 8

The label says use in children under 8 years of age is not recommended because of tooth and bone effects. Pediatric studies are ongoing, and the label may change.

Breastfeeding

Tetracyclines are excreted in human milk, and the amount absorbed by a breastfed infant is not known. The label advises that breastfeeding is not recommended during treatment and for 4 days after the last dose.

Common Side Effects

Nausea and Vomiting

Nausea and vomiting are the most common adverse reactions. In OASIS-1, which used an IV-to-oral approach, nausea occurred in about 12 percent and vomiting in about 5 percent. In OASIS-2, which used an oral loading dose, nausea was about 30 percent and vomiting about 17 percent. Taking the medicine as directed can help limit these effects.

Infusion Site Reactions

Pain, redness, or swelling at the IV site can occur, particularly with peripheral lines. Report any unusual pain or swelling promptly.

Liver Tests and Other Lab Changes

Liver enzyme increases, including ALT, AST, and gamma-glutamyl transferase, were reported as common in clinical data. Your team may check labs during longer treatment.

Other Reactions

Headache, insomnia, constipation, diarrhea, and changes in blood pressure have been reported. Photosensitivity can occur with tetracyclines, so use sun protection during treatment.

Serious Risks and Warnings

Hypersensitivity Reactions

Serious allergic reactions can occur. Hives, facial swelling, trouble breathing, or fainting require emergency care. Anyone with a known allergy to omadacycline or tetracycline-class drugs should not take Nuzyra.

Clostridioides difficile Infection

C. difficile-associated diarrhea can range from mild diarrhea to fatal colitis and can occur with nearly all antibacterial drugs. Diarrhea during or after treatment should be evaluated promptly, and treatment for C. difficile differs from treatment for the original infection.

Pseudotumor Cerebri

Increased pressure around the brain, called pseudotumor cerebri, has been reported with tetracyclines. Symptoms include severe headache, vision changes, or ringing in the ears. Report these symptoms right away.

Other Tetracycline Class Effects

Tetracyclines can cause fixed drug eruptions, increased BUN, acidosis, pancreatitis, and abnormal liver tests. Clinicians monitor for these in patients at risk.

The CABP Mortality Imbalance

What Was Observed

In the OPTIC pneumonia trial, eight deaths (2 percent) occurred in patients treated with omadacycline compared with four deaths (1 percent) in patients treated with moxifloxacin. The difference was small in absolute terms, but the label includes it under warnings and precautions.

How to Interpret It

Small numbers of deaths in a trial can create imbalances that are hard to interpret. The label notes the imbalance so prescribers can weigh the risk in individual patients. Pneumonia itself carries significant mortality, particularly in older adults and those with severe illness.

What Patients Should Know

Discuss any concerns about this imbalance with your clinician. Your clinician can compare your risk factors and the alternatives before deciding on a treatment.

Who Should Not Take Nuzyra

Known Hypersensitivity

People with known hypersensitivity to omadacycline or other tetracycline-class drugs should not take Nuzyra.

Children Under 8

Use is not recommended in children under 8 because of tooth and bone effects.

Pregnancy and Breastfeeding

These require individualized decisions. Pregnancy carries fetal and bone-growth concerns, and breastfeeding is not recommended during treatment and for 4 days after the last dose.

Kidney or Liver Disease

Patients with significant kidney or liver disease need individualized assessment. Your team may adjust monitoring or choose an alternative.

Drug Interactions

Minerals and Antacids

Antacids, calcium, iron, zinc, and magnesium supplements can reduce absorption of tetracycline-class drugs. Separate these from your dose as your pharmacist directs.

Blood Thinners and Other Drugs

Tetracyclines can affect how some anticoagulants work, so your team may monitor clotting tests. Give your care team a full list of medications, including over-the-counter products and supplements.

Oral Contraceptives

Ask your clinician whether antibiotics affect your contraception plan, and follow their advice about backup methods.

How Nuzyra Compares With Other Options

Moxifloxacin

Moxifloxacin was the comparator in OPTIC. Fluoroquinolones carry their own warnings, including tendon, nerve, and heart-rhythm effects, so the choice depends on individual risk.

Linezolid

Linezolid was the comparator in OASIS. It offers IV and oral options for skin and some pneumonia infections but has its own warnings, including low platelet counts with longer courses.

Doxycycline and Minocycline

Older tetracyclines are inexpensive and widely used for many infections. Nuzyra's advantage is its labeled use for CABP and ABSSSI and its design against tetracycline resistance mechanisms, but its cost and labeling differ.

Antibiotic Stewardship

Use Only When Indicated

The label emphasizes using Nuzyra only for infections proven or strongly suspected to be caused by susceptible bacteria. Prescribing it for viral infections or non-bacterial conditions offers no benefit and increases resistance risk.

Culture First

Cultures and susceptibility testing should guide therapy when they are available. Clinicians reassess the regimen as results return.

Resistance Monitoring

Resistance patterns are tracked by public health authorities and hospital laboratories. Report unusual findings to your infection prevention team.

Availability and Cost

Availability

Nuzyra is available through pharmacies and hospital systems. Availability of the IV form depends on the facility, and your care team can confirm stock.

Cost

Drug prices change over time and differ between IV and oral forms. Ask your pharmacist or insurer for current pricing. Compared with generic tetracyclines, branded omadacycline is more expensive.

Insurance Coverage

Coverage for FDA-approved indications is typically more straightforward. Prior authorization may be required, and your pharmacy team can help.

Questions to Ask Your Care Team

• Is my infection caused by an organism susceptible to omadacycline?
• Am I a candidate for switching from IV to tablets, and when?
• What is my exact dose and schedule, and how should I take the tablets?
• Which of my medicines, minerals, or supplements should I separate from the dose?
• What signs of C. difficile or pseudotumor cerebri should make me call right away?
• If I could become pregnant, what should I know before starting?

Frequently Asked Questions

Q: What is Nuzyra used for?

A: Nuzyra is approved for adults with community-acquired bacterial pneumonia and acute bacterial skin and skin structure infections caused by susceptible organisms.

Q: When was Nuzyra approved?

A: The FDA approved it on October 2, 2018.

Q: Is Nuzyra a tetracycline?

A: Yes. It is a modernized tetracycline-class antibiotic, specifically an aminomethylcycline.

Q: Can I switch from IV to pills?

A: Yes, the label allows IV therapy to be followed by oral tablets at the same once-daily regimen. Your care team decides when a switch is appropriate.

Q: Can children take Nuzyra?

A: The label does not recommend use in children under 8 because of tooth discoloration and bone growth effects.

Q: Does Nuzyra stain teeth?

A: The warning concerns use during tooth development, including the last half of pregnancy, infancy, and childhood up to age 8. The discoloration can be permanent.

Q: Is Nuzyra the same as doxycycline?

A: They are related but distinct. Each has its own labeled uses and warnings. Nuzyra's labeled uses are CABP and ABSSSI.

Q: What should I do if I get diarrhea during treatment?

A: Contact your care team promptly. Persistent or bloody diarrhea needs evaluation, including testing for C. difficile.

Medical Disclaimer

This article is for general education only and does not provide medical advice, diagnosis, or treatment. Pneumonia and skin infections can be serious, and they require evaluation by a qualified clinician. Do not start, stop, or change any antibiotic without guidance from your care team. For dosing, interactions, and warnings, consult the current U.S. prescribing information on DailyMed. If you have high fever, trouble breathing, confusion, chest pain, spreading redness, or a severe headache with vision changes, seek emergency care immediately.

Sources and Further Reading

• U.S. FDA approval announcement for Nuzyra (omadacycline), October 2, 2018
• Nuzyra (omadacycline) U.S. Prescribing Information, including Warnings and Precautions on tooth development, bone growth, hypersensitivity, and C. difficile-associated diarrhea
• Drugs.com Nuzyra FDA approval history (approval date October 2, 2018)
• Paratek Pharmaceuticals clinical summaries of the OPTIC trial (CABP) and OASIS-1 and OASIS-2 trials (ABSSSI)
• Medscape and Healio coverage of the FDA approval, October 2018
• Review article: Omadacycline: A Newly Approved Antibacterial from the Class of Tetracyclines, Pharmaceuticals, 2019

This article reflects information available as of October 2026. Confirm current prescribing details with your healthcare provider and the latest FDA labeling. For more on antibiotic options, visit MyOnlineMedShop blog or contact us.