Indications And Dosing Regimens - NAPLEX

Fidaxomicin $200\text{ mg}$ PO BID for $10$ days. Inhibits C. difficile RNA polymerase, providing high efficacy and lower recurrence rates compared to vancomycin for initial infections.

Ceftriaxone $500\text{ mg}$ IM once (add doxycycline if chlamydia not excluded). High-dose ceftriaxone ensures effective treatment of gonorrhea with added doxycycline to cover potential chlamydial co-infection.

Doxycycline $100\text{ mg}$ PO BID for $7$ days. Provides effective intracellular activity against Chlamydia trachomatis, ensuring clearance in uncomplicated genital infections.

Nitrofurantoin $100\text{ mg}$ PO BID for $5$ days. Recommended as first-line due to high efficacy against E. coli with low resistance rates and favorable safety profile in nonpregnant women without complicating factors.

Benzathine penicillin G $2.4\text{ million units}$ IM once. Delivers treponemacidal levels to eradicate Treponema pallidum in early stages, preventing progression to secondary syphilis.

Valacyclovir $500\text{ mg}$ PO BID for $3$ days. Suppresses herpes simplex virus replication during outbreaks, reducing lesion duration and viral shedding in recurrent episodes.

Valacyclovir $1\text{ g}$ PO TID for $7$ days. Inhibits varicella-zoster virus replication to shorten rash duration and reduce postherpetic neuralgia risk in immunocompetent adults.

Oseltamivir $75\text{ mg}$ PO daily for $7$ days after last exposure. Prevents influenza replication in exposed individuals, reducing infection risk in close contacts during outbreaks.

Oseltamivir $75\text{ mg}$ PO BID for $5$ days. Inhibits influenza neuraminidase to reduce viral replication and symptom duration when started within 48 hours of onset.

Benzathine penicillin G $2.4\text{ million units}$ IM weekly for $3$ doses. Ensures prolonged treponemacidal activity to treat potential persistent organisms in latent stages without neurologic involvement.

TMP-SMX DS $160/800\text{ mg}$ PO BID for $3$ days. Provides effective coverage against susceptible uropathogens with a short course to minimize resistance development when local resistance is below 20%.

Fosfomycin tromethamine $3\text{ g}$ PO once. Single-dose administration inhibits bacterial cell wall synthesis, offering convenience and high efficacy for uncomplicated cases caused by susceptible organisms.

Azithromycin $500\text{ mg}$ PO day $1$, then $250\text{ mg}$ daily days $2$–$5$. This macrolide regimen covers atypical pathogens like Mycoplasma and Chlamydia, suitable for healthy outpatients with low risk of resistance.

Doxycycline $100\text{ mg}$ PO BID for $5$–$7$ days. Offers broad coverage including atypicals and some gram-positives, serving as an alternative for patients intolerant to macrolides or beta-lactams.

Vancomycin $125\text{ mg}$ PO QID for $10$ days. Targets C. difficile toxins directly in the gut with minimal systemic absorption, standard for initial mild episodes to reduce recurrence risk.

Metronidazole $500\text{ mg}$ PO BID for $7$ days. Achieves high tissue concentrations to eradicate Trichomonas vaginalis, preferred for its efficacy and tolerability in symptomatic women.

Isoniazid + rifapentine once weekly for $12$ weeks (directly observed or self-administered per protocol). Short-course combination targets latent Mycobacterium tuberculosis with high completion rates and efficacy equivalent to longer regimens.

Prednisone $40$–$60\text{ mg}$ PO daily for $5$–$7$ days. Provides rapid anti-inflammatory effects to reduce airway inflammation and improve lung function in acute exacerbations.

Levothyroxine about $1.6\ \frac{\text{mcg}}{\text{kg}}$ PO daily (full replacement in healthy adults). Weight-based dosing approximates full thyroid hormone replacement to normalize TSH levels without overtreatment in euthyroid goal.

Omeprazole $20\text{ mg}$ PO daily for $4$–$8$ weeks. Suppresses gastric acid production to promote esophageal healing and symptom relief in erosive or non-erosive reflux disease.

Lisinopril $10\text{ mg}$ PO daily (lower if on diuretic or CKD per clinician judgment). Initiates ACE inhibition at a dose balancing efficacy and tolerability, adjustable based on blood pressure response and comorbidities.

Metformin IR $500\text{ mg}$ PO daily or BID with meals; titrate weekly as tolerated. Starts at low dose to minimize gastrointestinal side effects while improving glycemic control through reduced hepatic glucose production.