Condition Guide

Medications for Bacterial Infections

ICD-10: A49

Key Takeaways

Antibiotic selection should be guided by the suspected organism, local resistance patterns, and patient-specific factors (allergies, renal function, drug interactions).
Amoxicillin and amoxicillin-clavulanate are first-line for most community-acquired bacterial infections (sinusitis, otitis media, dental infections, UTIs in some regions).
Fluoroquinolones (ciprofloxacin, levofloxacin) should be reserved for serious infections — overuse has driven resistance and they carry risks of tendon rupture, peripheral neuropathy, and aortic aneurysm.
Azithromycin (Z-pack) is widely overused for respiratory infections — most acute bronchitis is viral and does not require antibiotics.
MRSA (methicillin-resistant Staphylococcus aureus) requires specific antibiotics — trimethoprim-sulfamethoxazole (Bactrim) for mild skin infections; vancomycin for serious infections.

Overview

Bacterial Infections affects approximately Very common — most people experience multiple bacterial infections per year.

Total Medications

Drug Classes

Off-Label Uses

Drug Classes for Bacterial Infections

Pharmacist-reviewed overview of each medication class, how it works, and when it's used.

Penicillins

First-LineGeneric Available

Mechanism of Action

Inhibit bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), preventing cross-linking of peptidoglycan chains. Beta-lactam ring is essential for activity; beta-lactamase-producing bacteria can inactivate penicillins.

Common Examples

AmoxicillinAmoxicillin-clavulanate (Augmentin)AmpicillinDicloxacillinPiperacillin-tazobactam (Zosyn)

Clinical Notes

Amoxicillin is first-line for strep throat, otitis media, sinusitis (bacterial), and dental infections. Amoxicillin-clavulanate adds beta-lactamase inhibitor coverage for resistant organisms. True penicillin allergy is rare — most patients reporting 'penicillin allergy' can safely receive penicillins after allergy evaluation.

Common Side Effects

Diarrhea (especially amoxicillin-clavulanate)
Rash
Allergic reactions (anaphylaxis — rare)
C. difficile colitis

Cephalosporins

First-LineGeneric Available

Mechanism of Action

Beta-lactam antibiotics that inhibit cell wall synthesis. Successive generations have broader gram-negative coverage. Cross-reactivity with penicillin allergy is low (~1–2%) for 2nd–5th generation cephalosporins.

Common Examples

Cephalexin (Keflex) — 1st genCefuroxime — 2nd genCeftriaxone — 3rd genCefdinir — 3rd genCeftaroline — 5th gen (MRSA coverage)

Clinical Notes

Cephalexin is first-line for skin and soft tissue infections (non-MRSA). Ceftriaxone is the most commonly used IV antibiotic for community-acquired pneumonia, UTIs, and many serious infections. Cefdinir is a common oral option for otitis media and sinusitis.

Common Side Effects

Diarrhea
Rash
Allergic reactions
C. difficile colitis

Macrolides

Second-LineGeneric Available

Mechanism of Action

Inhibit bacterial protein synthesis by binding to the 50S ribosomal subunit, preventing translocation. Bacteriostatic against most organisms.

Common Examples

Azithromycin (Zithromax, Z-pack)Clarithromycin (Biaxin)Erythromycin

Clinical Notes

Azithromycin is the most prescribed antibiotic in the US but is widely overused. Indicated for atypical pneumonia (Mycoplasma, Chlamydophila), pertussis, and as an alternative for penicillin-allergic patients. High rates of macrolide resistance in Streptococcus pneumoniae limit use for community-acquired pneumonia.

Common Side Effects

GI upset (nausea, diarrhea)
QT prolongation (cardiac arrhythmia risk)
Hearing loss (high doses)
Drug interactions (clarithromycin is a strong CYP3A4 inhibitor)

Fluoroquinolones

Second-LineGeneric Available

Mechanism of Action

Inhibit bacterial DNA gyrase and topoisomerase IV, preventing DNA replication and transcription. Bactericidal with excellent tissue penetration.

Common Examples

Ciprofloxacin (Cipro)Levofloxacin (Levaquin)Moxifloxacin (Avelox)

Clinical Notes

Reserve for serious infections (complicated UTIs, pyelonephritis, hospital-acquired pneumonia, anthrax exposure) or when first-line agents cannot be used. FDA black box warnings for tendinitis/tendon rupture, peripheral neuropathy, CNS effects, and aortic aneurysm. Avoid for uncomplicated UTIs, sinusitis, and bronchitis.

Common Side Effects

Tendinitis and tendon rupture
Peripheral neuropathy
CNS effects (insomnia, anxiety, seizures)
QT prolongation
Photosensitivity
C. difficile colitis

Sulfonamides / Trimethoprim

TMP-SMX

First-LineGeneric Available

Mechanism of Action

Trimethoprim-sulfamethoxazole (TMP-SMX) inhibits sequential steps in bacterial folate synthesis, producing a synergistic bactericidal effect. Effective against many gram-positive and gram-negative organisms including MRSA.

Common Examples

Trimethoprim-sulfamethoxazole (Bactrim, Septra)

Clinical Notes

First-line for uncomplicated UTIs (where resistance rates are <20%), community-acquired MRSA skin infections, and Pneumocystis jirovecii pneumonia (PCP) prophylaxis and treatment. Avoid in sulfa-allergic patients and in the third trimester of pregnancy.

Common Side Effects

Rash (including Stevens-Johnson syndrome — rare)
Hyperkalemia
Elevated creatinine (competes with creatinine secretion)
Bone marrow suppression with long-term use
Sulfa allergy cross-reactivity

All Medications

FDA-approved and commonly used medications for Bacterial Infections in our database.

Off-Label Uses

Semaglutide

(Ozempic)Off-Label

Semaglutide is a once-weekly (or once-daily oral) GLP-1 receptor agonist that lowers blood sugar and reduces body weight by mimicking the natural gut hormone GLP-1. It is sold under three brand names — Ozempic (injectable, type 2 diabetes), Wegovy (injectable, weight management), and Rybelsus (oral tablet, type 2 diabetes) — all manufactured by Novo Nordisk. Clinical trials show it reduces HbA1c by up to 2.0 percentage points and body weight by up to 15% at the highest injectable dose.

$935–$1,349/month

Omeprazole

(Prilosec)Off-Label

Omeprazole (brand name: Prilosec) is a proton pump inhibitor (PPI) available both over-the-counter and by prescription. It reduces stomach acid and is used to treat heartburn, GERD, and stomach ulcers.

$4–$25/month

Generic Available

Lovastatin

(Lovastatin)Off-Label

LOVASTATIN (brand name: Lovastatin) is a statin (HMG-CoA reductase inhibitor). Indications and Usage Therapy with lovastatin should be a component of multiple risk factor intervention in those individuals with dyslipidemia at risk for atherosclerotic vascular disease. Lovastatin should be used in addition to a diet restricted in saturated fat and cholesterol as part of a…

$10-$30/month

Dorzolamide Hydrochloride Timolol Maleate

(Dorzolamide Hydrochloride Timolol Maleate)Off-Label

DORZOLAMIDE HYDROCHLORIDE TIMOLOL MALEATE (brand name: DORZOLAMIDE HYDROCHLORIDE TIMOLOL MALEATE) is a Beta-Blockers. 1 INDICATIONS & USAGE Dorzolamide hydrochloride and timolol maleate ophthalmic solution is indicated for the reduction of elevated intraocular pressure (IOP) in patients with open-angle glaucoma or ocular hypertension who are insufficiently responsive to beta-blockers (failed to achieve target IOP…

$50–$150/month

Timolol Maleate

(Timolol Maleate)Off-Label

Timolol Maleate is an eye drop medication used to treat high pressure inside the eye. It works by helping to reduce the amount of fluid your eye produces, which in turn lowers the pressure. This medication is primarily prescribed for conditions like ocular hypertension and open-angle glaucoma to help protect your vision.

$50–$150/month

Sertraline Hydrochloride

(Sertraline hydrochloride)Off-Label

Sertraline hydrochloride is an antidepressant medication belonging to a group called selective serotonin reuptake inhibitors (SSRIs). It helps improve mood and reduce symptoms by affecting a natural substance in the brain called serotonin. This medication is used to treat various conditions like depression, obsessive-compulsive disorder, panic disorder, post-traumatic stress disorder, social anxiety disorder, and premenstrual dysphoric disorder.

$10–$50/month

Escitalopram Oral

(Escitalopram Oral Solution)Off-Label

Escitalopram oral is a medication known as an antidepressant (specifically, an SSRI) that helps improve mood. It is primarily used to treat major depressive disorder in adults and children aged 12 and older, as well as generalized anxiety disorder in adults, by helping to restore the balance of certain natural substances in the brain.

$200–$500/month

Liraglutide

(Victoza)Off-Label

Liraglutide (Victoza) is a type of medicine that mimics a natural hormone in your body. It is prescribed to help adults and children aged 10 and older with type 2 diabetes manage their blood sugar levels, and it can also lower the risk of serious heart problems like heart attack or stroke in adults with type 2 diabetes and existing heart disease. It works by helping your body release insulin when needed and reducing the amount of sugar your liver makes.

$900–$1,200/month

Empagliflozin

(Jardiance)Off-Label

Empagliflozin (Jardiance) is a medication that helps your kidneys remove extra sugar from your body through urine. It is prescribed to treat type 2 diabetes by lowering blood sugar, and also helps reduce the risk of heart-related problems and hospitalizations in adults with heart failure or chronic kidney disease.

$550–$700/month

Bexagliflozin

(Bexagliflozin)Off-Label

Bexagliflozin is a medication used alongside diet and exercise to help adults with type 2 diabetes manage their blood sugar levels. It works by helping your kidneys remove more sugar from your body through your urine. This helps lower high blood sugar.

$350–$600/month

Empagliflozin, Linagliptin, Metformin Hydrochloride

(Trijardy XR)Off-Label

Trijardy XR is a combination medicine used by adults with type 2 diabetes, along with diet and exercise, to help lower blood sugar levels. It combines three different medications that work in various ways to help your body manage sugar. For some adults with type 2 diabetes and existing heart disease, it can also help reduce the risk of heart-related death.

$600–$900/month

Empagliflozin, Metformin Hydrochloride

(Synjardy XR)Off-Label

Synjardy XR is a combination medicine that helps adults and children (10 years and older) with type 2 diabetes manage their blood sugar. It works by helping your body remove excess sugar through your urine and by reducing the amount of sugar your liver makes and your body absorbs. For adults with type 2 diabetes and established heart disease, it also helps reduce the risk of cardiovascular death.

$500–$800/month

Dapagliflozin

(Dapagliflozin)Off-Label

Dapagliflozin (brand name: DAPAGLIFLOZIN) is a medication that helps your kidneys remove excess sugar from your body. It is used to treat type 2 diabetes, heart failure, and chronic kidney disease by improving blood sugar control and protecting your heart and kidneys.

$450–$600/month

Canagliflozin

(Invokana)Off-Label

Invokana (canagliflozin) is a medication for adults and children aged 10 and older with type 2 diabetes. It helps lower blood sugar by causing the kidneys to remove more sugar from the body through urine. For adults with type 2 diabetes and existing heart or kidney disease, Invokana also helps reduce the risk of serious heart problems, hospitalization for heart failure, and progression of kidney disease.

$500–$750/month

Ertugliflozin

(Steglatro)Off-Label

STEGLATRO (ertugliflozin) is a medication called an SGLT2 inhibitor, used to help adults with type 2 diabetes manage their blood sugar levels. It works by helping your kidneys remove more sugar from your body through your urine, which lowers your overall blood sugar. This medication is used along with diet and exercise.

$400–$700/month

Valsartan

(Valsartan)Off-Label

VALSARTAN (brand name: Valsartan) is a ARBs. 1 INDICATIONS & USAGE Valsartan is an angiotensin II receptor blocker (ARB) indicated for: Hypertension in adults and children six years and older, to lower blood pressure. Lowering blood pressure reduces the risk of fatal and nonfatal cardiovascular events, primarily strokes and myocardial…

$10–$40/month

Diclofenac Sodium

(Diclofenac Sodium)Off-Label

DICLOFENAC SODIUM (brand name: Diclofenac Sodium) is a NSAIDs. 1 INDICATIONS AND USAGE Diclofenac sodium topical solution, USP is indicated for the treatment of signs and symptoms of osteoarthritis of the knee(s) (1). Diclofenac sodium topical solution is a nonsteroidal anti-inflammatory drug indicated for the treatment of signs and symptoms of osteoarthritis…

$10-$30/month

Diclofenac Sodium, Capsaicin

(Lextol)Off-Label

DICLOFENAC SODIUM, CAPSAICIN (brand name: Lextol) is a NSAIDs. 1 INDICATIONS AND USAGE Diclofenac sodium topical solution, USP is indicated for the treatment of signs and symptoms of osteoarthritis of the knee(s) (1). Diclofenac sodium topical solution is a nonsteroidal anti-inflammatory drug indicated for the treatment of signs and symptoms of osteoarthritis…

$200–$500/month

Ketorolac Tromethamine

(Ketorolac Tromethamine)Off-Label

KETOROLAC TROMETHAMINE (brand name: Ketorolac Tromethamine) is a NSAIDs. INDICATIONS AND USAGE Carefully consider the potential benefits and risks of Ketorolac Tromethamine Tablets USP and other treatment options before deciding to use Ketorolac Tromethamine Tablets USP. Use the lowest effective dose for the shortest duration consistent with individual patient treatment…

$10–$50/month

How to Choose the Right Medication

Clinical decision factors used by prescribers when selecting a treatment.

1For uncomplicated UTI: TMP-SMX (if local resistance <20%) or nitrofurantoin (Macrobid) — avoid fluoroquinolones.
2For strep throat: amoxicillin 10 days, or penicillin V — azithromycin only if penicillin-allergic.
3For community-acquired pneumonia (outpatient, no comorbidities): amoxicillin or doxycycline — azithromycin if atypical organisms suspected.
4For skin and soft tissue infections (non-MRSA): cephalexin — TMP-SMX or doxycycline if MRSA suspected.
5For sinusitis: most cases are viral — antibiotics only if symptoms persist >10 days or are severe; amoxicillin-clavulanate if antibiotics indicated.
6Always check local antibiogram data for resistance patterns — what works in one region may not work in another.

Monitoring & Follow-Up

Reassess at 48–72 hours — if not improving, reconsider diagnosis, culture results, and antibiotic choice.
Send cultures before starting antibiotics whenever possible — this guides de-escalation.
For TMP-SMX: monitor potassium and creatinine, especially in elderly or CKD patients.
For fluoroquinolones: ask about tendon pain at follow-up; stop immediately if tendinitis develops.
Educate patients to complete the full antibiotic course and not to share or save antibiotics.

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Frequently Asked Questions

How do I know if my infection is bacterial or viral?

Distinguishing bacterial from viral infections is clinically challenging. General indicators that suggest bacterial infection include: symptoms lasting more than 10 days without improvement, high fever (>103°F), purulent (thick, colored) discharge, localized pain and swelling, and elevated white blood cell count with left shift on CBC. However, many of these features overlap with viral infections. Rapid strep tests, urinalysis, and cultures can help confirm bacterial infections in specific contexts. Most upper respiratory infections, bronchitis, and sore throats are viral and do not benefit from antibiotics.

What is antibiotic resistance and why does it matter?

Antibiotic resistance occurs when bacteria evolve mechanisms to survive exposure to antibiotics — by producing enzymes that inactivate the antibiotic (beta-lactamases), modifying the antibiotic's target, or pumping the antibiotic out of the cell. Resistance is driven by antibiotic overuse and misuse. The WHO estimates that antibiotic-resistant infections cause 700,000 deaths per year globally, projected to reach 10 million by 2050 if trends continue. Each unnecessary antibiotic prescription contributes to resistance — this is why antibiotics should only be used when genuinely indicated.

References & Clinical Sources

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Medical Disclaimer

The information on RxGuide is intended for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician, pharmacist, or other qualified health provider with any questions you may have regarding a medical condition or medication. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.