Administering medications through a Nasogastric (NG) tube is a common practice when a person cannot swallow safely or effectively. An NG tube is a thin, flexible tube inserted through the nose into the stomach, primarily used for enteral feeding or removing stomach contents (decompression). This route allows essential treatments to reach the gastrointestinal tract, bypassing the mouth. This method is necessary for patients who require short-term tube feeding or have conditions preventing oral intake. However, this routine procedure demands strict adherence to preparation and administration protocols to prevent complications.
Preparing Medications for Tube Delivery
The preparation of medication is an important first step, focusing on converting the drug into a form that will pass easily through the narrow tube without clogging. Liquid medications are the preferred form for administration through an NG tube because they require the least amount of manipulation. Many liquid drugs, however, have a high viscosity or osmolality, which can cause tube clogging or gastrointestinal side effects such as diarrhea, so they should often be diluted with purified water just before administration.
If a suitable liquid form is not available, immediate-release tablets or capsules may be used, but only after consultation with a pharmacist to ensure they are safe to modify. Solid medication must be crushed into a very fine powder using a mortar and pestle or a pill crusher, ensuring no visible clumps remain. This fine powder is then thoroughly dissolved in a small amount of water, typically 15 to 30 milliliters (mL), to create a smooth, suspension-like mixture.
Each medication must be prepared and dissolved individually in its own cup; they must never be mixed together. Mixing multiple medications can lead to unpredictable drug interactions, altered absorption, or immediate tube blockage. Purified water, such as sterile or distilled water, is suggested over tap water for dilution, as the minerals and contaminants in tap water could potentially interact with the drug.
Safe Administration Procedure
Before any medication is administered, the placement of the NG tube must be verified to ensure the tip is correctly located in the stomach. The most reliable method for initial confirmation is a chest or abdominal X-ray. For ongoing bedside checks before each use, aspirate a small amount of fluid from the tube and test its acidity using pH paper. A gastric pH reading of 5.5 or below is generally considered a strong indication of correct placement in the stomach.
Once the tube placement is confirmed, the first step is to flush the tube with a small volume of water, usually 15 to 30 mL for adults. This initial flush confirms the tube is patent and helps clear any residual feeding formula. The prepared medication is then administered using a syringe attached to the NG tube port. Remove the plunger to allow the solution to flow by gravity, or use a gentle push method to instill the medication slowly and steadily.
After the entire dose of the first medication has flowed in, the tube must be flushed again with a small volume of water, typically 10 to 15 mL, before administering the next drug. This flush is performed between each separate medication to prevent drugs from interacting within the tube. Once all medications have been given, a final flush of 15 to 30 mL of water is essential to clear the tube completely and maintain its patency.
Recognizing and Preventing Complications
One of the most frequent complications is tube clogging, which is commonly caused by improper preparation, such as not crushing tablets to a fine enough powder, or by failing to flush the tube adequately before and after administration. To prevent this, the flushing volumes and techniques must be strictly followed, ensuring that each medication dose is followed by water.
Certain medication forms must never be administered through an NG tube because they will cause a blockage or lose their therapeutic effect. This includes sustained-release, extended-release, or enteric-coated tablets, which are designed to dissolve slowly or in the intestines and would be rendered ineffective if crushed. Sublingual or chewable tablets are also unsuitable, as their absorption mechanism is not compatible with the gastrointestinal route.
If a tube becomes clogged, the first-line intervention is to attempt to clear it by gentle irrigation with warm water using a syringe. A systematic approach of pushing and pulling the syringe plunger, followed by a short soaking period, may help dissolve the blockage. Another serious risk is pulmonary aspiration, which is the entry of stomach contents or medication into the lungs, often due to an incorrectly placed tube. To mitigate this, the patient should be kept in an elevated position, with the head of the bed raised at least 30 degrees, for at least 30 minutes following administration.