Cephalexin is a commonly prescribed medication that belongs to the class of antibiotics known as cephalosporins, used to treat a variety of bacterial infections throughout the body. This medication works by interfering with the bacteria’s ability to build a cell wall, which ultimately kills the organism. The liquid form of cephalexin, referred to as an oral suspension, is prepared by a pharmacist who mixes the dry powder with a specific amount of water before dispensing it to the patient.
Storage Requirements for Liquid Cephalexin
The reconstituted liquid cephalexin suspension generally requires refrigeration to maintain its effectiveness and chemical stability. Storing the antibiotic at cooler temperatures, specifically between $2^\circ \text{C}$ and $8^\circ \text{C}$ ($36^\circ \text{F}$ and $46^\circ \text{F}$), slows down the rate of chemical degradation. This cooling process helps ensure that the concentration of the active drug remains high enough to fight the infection over the entire treatment period. If the suspension is allowed to get too warm, the drug can break down more quickly, reducing its potency.
The manufacturer’s label instructs storing the product in a refrigerator, and this is the default procedure. The suspension should not be frozen, as this destroys the drug’s physical integrity and makes proper dosing impossible. In some cases, the pharmacist or the packaging label may instruct storage at controlled room temperature ($20^\circ \text{C}$ to $25^\circ \text{C}$ or $68^\circ \text{F}$ to $77^\circ \text{F}$). This variation depends on the specific formulation, so always check the label or consult your pharmacist.
Understanding Stability and Expiration
The stability of cephalexin changes once the powder is mixed with water to create the oral suspension. Reconstitution begins a countdown for the medication’s expiration, regardless of storage temperature. The liquid form of cephalexin is chemically stable for 14 days after the pharmacist prepares it. Beyond this two-week window, the active drug degrades and loses potency.
Cephalexin molecules break down chemically in the presence of water over time, causing a loss of effectiveness. Using the antibiotic after 14 days risks treatment failure or the development of antibiotic-resistant organisms because the dose may not contain enough active ingredient. Discard any remaining suspension exactly 14 days after it was mixed, even if the liquid still looks and smells normal. This 14-day limit safeguards against administering a sub-therapeutic dose.
Safe Administration and Disposal
Proper administration ensures the patient receives the full prescribed dose. Since the medication is a suspension, drug particles can settle at the bottom over time. Shake the bottle vigorously before drawing out each dose to ensure even distribution.
The dose should be measured using the specialized oral syringe, dropper, or measuring spoon provided by the pharmacy, not a common household spoon. After the full course of treatment is completed or the 14-day expiration period has passed, any unused portion must be disposed of safely.
Disposal Methods
The safest method is to utilize a drug take-back program or a mail-back envelope, often available at local pharmacies or police departments. If a take-back option is not available, the liquid must be prepared for household trash disposal to prevent accidental ingestion.
- Mix the unused liquid with an undesirable substance, such as used coffee grounds or cat litter.
- Place this mixture into a sealed plastic bag or container.
- Throw the sealed container into the household trash.