Famotidine is an H2-receptor antagonist that decreases the amount of acid produced in the stomach. Available over-the-counter and by prescription, this medication is commonly used to treat conditions like heartburn, acid reflux, and ulcers. Proper storage is foundational to ensuring that any medication maintains its full effectiveness and remains safe to use. The storage requirements for famotidine vary significantly depending on its specific form.
Standard Storage for Tablets
Famotidine tablets and chewable forms should not be refrigerated. The standard guidance for these solid dosage forms is to keep them at controlled room temperature, typically defined as 20°C to 25°C (68°F to 77°F). Temporary excursions between 15°C and 30°C (59°F and 86°F) are usually permissible.
The primary concern for tablets is protection from excess heat and moisture. Storing tablets in a cool, dry location, such as a bedroom drawer or cabinet, away from direct sunlight is the best practice. Placing tablets in a refrigerator can expose them to high humidity when the container is opened, which can compromise the integrity of the active ingredient and the tablet structure itself.
Specific Guidelines for Oral Suspensions
The storage instructions for liquid famotidine, known as an oral suspension, differ substantially from the tablets. Famotidine oral suspension is often supplied as a dry powder that must be mixed with water by a pharmacist before dispensing. Once constituted, the liquid form has a much shorter expiration period than the tablets.
Many commercially prepared suspensions are stable at controlled room temperature for a limited time, such as 30 days after mixing. However, to maximize the shelf life of the reconstituted drug, especially in extemporaneously compounded preparations, refrigeration between 2°C and 8°C (36°F and 46°F) is often recommended. The liquid must be protected from freezing, as this can severely damage the suspension and make the medication ineffective.
Why Temperature and Humidity Affect Medication
Temperature and humidity are the main environmental factors that drive chemical degradation in pharmaceuticals. Famotidine, like many drug compounds, is susceptible to chemical breakdown over time. Excessive heat provides the energy necessary to accelerate these reactions, causing the active drug molecule to change into an inactive form.
Moisture in the air, or humidity, facilitates hydrolysis, a degradation process where water molecules break down the chemical bonds in the drug structure. Humidity can also increase the rate of photodegradation, which is the breakdown caused by light exposure. Maintaining storage conditions within the recommended temperature and humidity ranges ensures the drug’s potency remains consistent throughout its labeled shelf life.
Recognizing Compromised Medication and Safe Disposal
Improper storage can lead to medication compromise, which is often visible to the user. For oral suspensions, signs of damage include an unusual change in color, a noticeable odor, or the presence of crystals that do not dissolve when shaken. Tablets may show signs of crumbling, cracking, or discoloration, which indicates the integrity of the dosage form has been compromised by moisture or heat.
When medication is expired or compromised, the safest disposal method is a drug take-back program, which may be available at local pharmacies or police departments. If a take-back option is not readily accessible, the U.S. Food and Drug Administration (FDA) recommends mixing the medication with an unappealing substance, such as used coffee grounds or cat litter. This mixture should then be placed into a sealed plastic bag or container before being thrown into the household trash, preventing accidental ingestion by children or pets.