Used lidocaine patches should be folded in half with the sticky sides pressed together, then thrown away in household trash, out of reach of children and pets. Lidocaine patches are not on the FDA’s flush list, so flushing is not recommended. But these patches deserve more care than you might expect during disposal, because even a used patch still contains a surprisingly large amount of medication.
Why Used Patches Still Need Careful Disposal
A single prescription lidocaine patch (5%) contains 700 mg of lidocaine. After a full 12-hour wear period, only about 3% of that dose gets absorbed through your skin. That means at least 665 mg of active lidocaine remains in the patch after you peel it off. That’s nearly as much drug as the patch started with.
This residual medication is what makes careless disposal risky. A toddler who finds a used patch in an open trash can, or a dog who chews one up, can be exposed to a dose large enough to cause serious harm. Lidocaine toxicity can cause seizures, breathing problems, and in severe cases, cardiac arrest. Young children are especially vulnerable because of their small body weight. A case report in the medical literature describes an 18-month-old who went into cardiorespiratory arrest after accidental lidocaine ingestion. These incidents are rare, but they’re preventable with proper disposal.
Step-by-Step Disposal for Used Patches
After you remove a lidocaine patch from your skin, fold it in half so the adhesive sides stick to each other. This traps the remaining medication inside and makes it harder for a child or pet to access the sticky, drug-coated surface. From there, place the folded patch in a sealed plastic bag or container before putting it in your household trash. Keep it somewhere children and animals cannot reach, ideally in a bin with a secure lid.
This applies to both prescription 5% patches and over-the-counter 4% patches. The OTC versions contain less lidocaine per patch, but the same disposal steps are appropriate for both strengths.
How to Dispose of Unused or Expired Patches
Full, unused patches contain even more lidocaine than used ones, so they require extra caution. The FDA’s preferred method for most non-flush-list medications is a drug take-back program. You have two main options:
- Drug take-back locations: Many pharmacies, hospitals, and law enforcement offices host permanent collection bins or periodic take-back events. You can find the nearest location through the DEA’s website at deatakeback.com or by calling (800) 882-9539.
- Mail-back envelopes: Some pharmacies and community programs offer prepaid envelopes designed for mailing unused medications to approved disposal facilities.
If neither option is available to you, the FDA recommends disposing of unused patches in your household trash using these steps: remove the patches from their original packaging, mix them with something unpleasant like used coffee grounds, dirt, or cat litter, seal the mixture in a plastic bag, and place it in your trash. The unappealing substance discourages anyone (including pets) from digging through the bag. Scratch out any personal information on the prescription label before recycling or discarding the empty box.
Why You Shouldn’t Flush Lidocaine Patches
The FDA maintains a “flush list” of medications considered so dangerous that flushing is preferable to the risk of someone finding them in the trash. This list is dominated by opioids like fentanyl patches, oxycodone, and morphine, along with a few non-opioid medications. Lidocaine patches are not on the flush list. Flushing introduces pharmaceuticals into the water supply, and since lidocaine patches don’t carry the same acute overdose risk as opioids, the environmental tradeoff isn’t justified. Stick with trash disposal or a take-back program.
Keeping Patches Secure Before Disposal
The window between removing a patch and throwing it away is when accidents are most likely to happen. Don’t leave a used patch sitting on a nightstand, countertop, or bathroom sink where a child could grab it. The sticky surface can adhere to skin on contact, and a curious toddler might put it in their mouth. Fold and dispose of the patch immediately after removal. If you’re storing unused patches, keep them in their sealed pouches in a location that’s out of sight and out of reach, just as you would with any other medication.