Cephalexin starts working quickly, often within an hour of the first dose, but noticeable improvement in symptoms typically takes about 2 to 3 days. It is important to continue taking the full prescribed course even if symptoms improve earlier to ensure the infection is fully cleared and to prevent antibiotic resistance.

Timing for Effectiveness

• Cephalexin begins killing bacteria rapidly after the first dose, with peak concentrations reached about one hour post-dose.
• Symptom improvement for infections such as skin or tooth infections may not be noticeable until 2 to 3 days after starting treatment.
• For most infections, patients can expect to start feeling better within a few days, depending on the infection type.

Treatment Recommendations

• Always take cephalexin exactly as prescribed and complete the full course.
• Do not stop early even if feeling better, as this can cause the infection to return and contribute to antibiotic resistance.
• If symptoms do not improve after 2 to 3 days or worsen at any time, contact a healthcare provider.

Additional Notes

• Cephalexin can be taken with or without food, but taking it on an empty stomach may optimize absorption.
• Side effects may include nausea, vomiting, diarrhea, and allergic reactions, among others.

This information applies generally but may vary based on the specific infection and individual health circumstances.