Cephalexin is a commonly prescribed antibiotic in Australia, widely used to treat bacterial infections such as respiratory tract infections, skin infections, urinary tract infections, and more. If you’ve been prescribed cephalexin or are considering it, you might wonder: how long does it take for cephalexin to clear an infection? This blog post will provide a clear, evidence-based answer tailored to the Australian context.
How Quickly Does Cephalexin Start Working?
Cephalexin begins to work soon after you take the first dose. Peak levels of the drug in the bloodstream are typically reached within an hour, allowing it to start attacking the bacteria responsible for the infection. However, symptoms usually take around 48 hours (2 days) to show noticeable improvement7.
This means while the antibiotic starts killing bacteria quickly, it may take a couple of days before you feel better.
Typical Duration of Treatment
The length of time you need to take cephalexin depends on the type and severity of the infection:
- Mild to moderate infections such as uncomplicated urinary tract infections, skin infections, or throat infections are usually treated for 7 to 14 days.
- For more severe infections or infections caused by less susceptible bacteria, longer courses or higher doses may be necessary, sometimes extending beyond 14 days.
- In some cases, treatment may be adjusted based on your response or if the infection recurs.
Australian clinical guidelines generally recommend a minimum of 5 to 7 days for common infections, with some conditions like streptococcal throat infections requiring at least 10 days to prevent complications.
When Should You Expect to Feel Better?
Most patients start to feel relief from symptoms within the first few days of treatment. If you do not notice any improvement after 48 to 72 hours, or if symptoms worsen, it is important to contact your healthcare provider.
Why Completing the Full Course Matters
Even if you feel better early on, it’s essential to complete the entire prescribed course of cephalexin. Stopping treatment too soon can allow some bacteria to survive, potentially leading to a return of the infection or development of antibiotic resistance.
Dosage and Administration in Australia
- Adults commonly take 250 mg every 6 hours or 500 mg every 12 hours, depending on the infection.
- Children’s doses are weight-based, usually between 25 to 50 mg/kg/day divided into multiple doses.
- Treatment duration and dosage may be adjusted for kidney function or severity of infection.
Summary
Cephalexin typically starts working within hours, but you should expect to see symptom improvement within about 48 hours. Most infections require 7 to 14 days of treatment to be fully cleared, depending on the infection’s nature and severity. Always follow your doctor’s instructions carefully, complete the full course, and consult your healthcare provider if symptoms do not improve or worsen.