Compounding Errors: What They Are, Why They Happen, and How to Stay Safe

When a pharmacist mixes ingredients to create a custom medication—like a dye-free version of a pill or a liquid form for a child who can’t swallow tablets—that’s compounding, the process of preparing personalized medications when commercially available options don’t work. Also known as custom pharmacy preparation, it’s a vital service for people with allergies, special dosing needs, or rare conditions. But when things go wrong, compounding errors can cause serious harm, even death.

These mistakes aren’t just about misreading a prescription. They happen because of poor labeling, wrong ingredient strength, cross-contamination, or using non-sterile equipment. A compounder might accidentally use the wrong chemical form of a drug—like mixing up potassium chloride instead of potassium citrate—or fail to check for interactions between ingredients. In one documented case, a patient lost vision after a compounded eye drop was contaminated with a toxic solvent. Another patient suffered kidney failure because a compounded pain cream contained 10 times the intended dose of a powerful steroid. These aren’t rare flukes. The FDA and state boards track hundreds of compounding errors every year, and many go unreported because patients never connect their symptoms to the medication.

What makes this worse is that compounding pharmacies, unlike big drug manufacturers, aren’t required to prove each batch is safe before it’s sold. They operate under looser rules, and oversight varies wildly by state. Some follow strict standards from the USP, while others cut corners. And because these medications are made to order, there’s no way to recall them all at once if something goes wrong. You might be the only one who gets the bad batch.

That’s why knowing what to look for matters. If your compounded medication looks different from last time—if the color, smell, or texture changed—ask why. If you’re given a new bottle without a clear label listing every ingredient and its strength, don’t take it. Check if the pharmacy is accredited by the PCAB (Pharmacy Compounding Accreditation Board). Ask if they test each batch for potency and purity. Most importantly, if you feel worse after starting a compounded drug, don’t assume it’s just side effects. It could be a mistake.

The posts below dig into the hidden risks behind everyday medications—from inactive ingredients that trigger reactions, to how generic drugs are tested for safety, to how post-marketing surveillance catches dangerous trends. You’ll find real stories, data, and practical steps to protect yourself from errors that most people never even think about. Whether you’re on a custom compound, a generic pill, or a new prescription, this collection gives you the tools to ask the right questions before you swallow anything.