Cephalexin (Keflex) Dosage for Canine Use
Cephalexin, often known by the brand name Keflex, is a common prescription antibiotic used by veterinarians to treat various bacterial infections in dogs, particularly skin infections (pyoderma), respiratory tract infections, and urinary tract infections. It belongs to the cephalosporin class of antibiotics. **It is absolutely vital to consult a licensed veterinarian** before administering Cephalexin or any antibiotic to your dog, as incorrect use can lead to antibiotic resistance or adverse side effects.
**Cephalexin is a prescription drug** and should only be used under the guidance of a professional who can diagnose the infection and determine the necessary length of treatment.
The Standard Dosage Guidelines
The dosing of Cephalexin is based on the dog's body weight and the severity of the infection. The standard veterinary therapeutic dose range is typically between $10 \text{ mg}$ and $15 \text{ mg}$ per pound of body weight ($10-15 \text{ mg}/\text{lb}$). This dose is generally administered two to three times per day.
The calculator uses the standard formula to find the dose required in milligrams ($Dose_{mg}$) based on the dog's weight in pounds ($Weight_{lb}$):
$$Dose_{mg} = Weight_{lb} \times R$$
Where $R$ is the prescribed dosage rate, typically $\mathbf{12.5 \frac{mg}{lb}}$ for a target dose. If the weight is entered in kilograms, it is first converted ($1 \text{ kg} \approx 2.2 \text{ lb}$).
Converting Milligrams to Tablets or Milliliters
Once the total dose in milligrams is determined, you must convert this into the physical amount to administer. The method depends on the form of the medication:
Capsules or Tablets:
Since Cephalexin often comes in standard sizes (like $250 \text{ mg}$ or $500 \text{ mg}$), the number of units ($U$) needed is found by rounding up the calculated dose to the nearest whole or half unit that meets or slightly exceeds the target dose:
$$V_{mL} = \frac{Dose_{mg}}{C_{liquid}} \quad \left( C_{liquid} \text{ in } \frac{mg}{mL} \right)$$
**Strong caution** must be used with liquid formulas to ensure precise measurement, as dispensing errors can occur easily.