Understanding the Link: Can the Patch Cause Diarrhea?

October 9, 2025 •

4 min read

In clinical trials for the Rivastigmine patch, up to 10% of patients reported experiencing diarrhea [1.3.1]. While transdermal patches are designed to deliver medication steadily through the skin, the question remains for many users: can the patch cause diarrhea and other systemic side effects?

Quick Summary

Yes, certain medication patches can cause diarrhea. This occurs because the drug enters the bloodstream and affects the entire body, including the gastrointestinal system. Specific patches, like those for dementia and pain, list diarrhea as a known side effect.

Key Points

Systemic Effect: Yes, medication from a patch enters the bloodstream and can affect the entire body, including the gastrointestinal tract, potentially causing diarrhea [1.3.4].
Specific Patches: Patches for dementia (Rivastigmine), pain (Fentanyl, Buprenorphine), and hormone replacement are known to have diarrhea as a possible side effect [1.3.2, 1.5.2, 1.9.1, 1.2.4].
Mechanism Varies: The cause can be related to the drug's primary action, such as how cholinesterase inhibitors increase gut activity [1.3.1] or how hormones influence motility [1.6.1].
Consult a Doctor: Never stop using a patch without medical advice, as this can cause withdrawal or other issues. A doctor can help manage side effects [1.3.3].
Management is Possible: For mild diarrhea, staying hydrated and adjusting your diet can help. For severe cases, a doctor might adjust the dose or change the medication [1.6.5, 1.2.1].
Opioid Complexity: While opioids are known for causing constipation, diarrhea can also occur, sometimes at the start of treatment or as a symptom of a serious condition like serotonin syndrome [1.5.1, 1.9.4].
Not All Patches: Some patches, like Scopolamine, are much more likely to cause constipation due to their anticholinergic effects that slow the gut [1.10.1].

The Surprising Link Between Your Skin and Your Gut

Transdermal patches represent a modern approach to medicine, offering a steady release of medication directly through the skin into the bloodstream [1.7.1]. This method is praised for its convenience and ability to bypass the digestive system's initial breakdown process, known as first-pass metabolism [1.8.5]. However, just because a medication doesn't start in the stomach doesn't mean it can't cause stomach problems. Once the active ingredient is in your circulatory system, it travels throughout your body, interacting with various organs, including your gastrointestinal (GI) tract. This systemic exposure is why a medication applied to your arm can lead to an upset stomach, nausea, or even diarrhea [1.7.2, 1.3.4].

How Can a Patch Lead to Diarrhea?

The mechanism isn't always direct, but it's pharmacologically sound. Different drugs have different effects. For example, cholinesterase inhibitors, a class of drugs used for dementia, increase cholinergic activity, which can lead to increased gastric acid secretion and GI motility [1.3.1]. Hormones like estrogen can also influence intestinal function because estrogen receptors are present throughout the GI tract [1.6.1]. Opioids can have complex effects; while they are commonly known to cause constipation, some patients experience diarrhea, especially during dose initiation or changes [1.5.1, 1.7.2]. In some documented cases, severe diarrhea from a fentanyl patch was observed within hours of application, which resolved after the patch was removed [1.5.1].

Common Patches Associated with Diarrhea

While many patches have a low incidence of this side effect, some are more commonly associated with it. It's important to note that skin irritation at the application site is the most frequent side effect for most patches [1.7.1, 1.7.3]. However, systemic effects do occur.

Rivastigmine (Exelon Patch)

Used to treat dementia associated with Alzheimer's and Parkinson's disease, the rivastigmine patch is well-known for its potential to cause gastrointestinal side effects [1.3.4]. Diarrhea is listed as a common side effect, affecting around 6% to 10% of users depending on the dosage [1.3.1]. These effects, including nausea and vomiting, are often why patients switch from the oral capsule to the patch, though they can still persist [1.3.3]. The drug works as a cholinesterase inhibitor, and this action can increase activity in the GI tract [1.3.1].

Opioid Patches (Fentanyl, Buprenorphine)

Opioid patches are powerful pain relievers. While constipation is the more famously associated side effect, diarrhea can also occur [1.8.4, 1.7.2]. With the fentanyl patch, diarrhea is listed as a potential side effect that may occur, especially during the first 72 hours of treatment or after a dose increase [1.5.1, 1.5.5]. Similarly, the buprenorphine patch lists diarrhea as a very common side effect, affecting up to 10.3% of users [1.9.1]. Diarrhea can also be a symptom of serotonin syndrome, a serious condition that can occur when taking these medications with other drugs that affect serotonin levels [1.9.4].

Hormone Patches (Estradiol, Birth Control)

Diarrhea is considered a less common side effect of estradiol patches used for hormone replacement therapy (HRT) [1.6.2]. However, hormones can affect GI motility, and some research has linked HRT to an increased risk of irritable bowel syndrome (IBS), which often involves diarrhea [1.6.1, 1.6.4]. Birth control patches, which also deliver hormones, can cause a range of side effects, including diarrhea, as the body adjusts to the new hormonal levels [1.2.5].

Nicotine Patches

Used for smoking cessation, nicotine patches can also cause gastrointestinal upset. Diarrhea is listed as a rare side effect for the transdermal patch formulation, though other GI symptoms like nausea and abdominal pain are more common [1.4.2, 1.4.4]. Nicotine itself can stimulate the digestive system, leading to these effects [1.4.3].

Comparison of Patches and GI Side Effects


Medication Patch	Primary Use	Likelihood of Causing Diarrhea	Common GI Side Effects	Note
Rivastigmine	Dementia	Common (6-19%) [1.3.1, 1.3.5]	Nausea, vomiting, diarrhea, loss of appetite [1.3.2]	The patch may offer fewer GI side effects than oral capsules, but they are still prevalent [1.3.3].
Fentanyl	Severe Pain	Occasional [1.5.3]	Constipation, nausea, vomiting, diarrhea [1.7.2]	Often occurs at treatment initiation or with dose increases [1.5.1].
Buprenorphine	Pain / Opioid Dependence	Very Common (up to 10.3%) [1.9.1]	Nausea, constipation, diarrhea, abdominal pain [1.9.1]	Diarrhea can also be a symptom of withdrawal if the patch is stopped suddenly [1.9.3].
Estradiol (HRT)	Menopause Symptoms	Less Common / Rare [1.6.2]	Nausea, bloating, abdominal cramps [1.2.1]	Hormones can influence gut motility and have been linked to IBS-like symptoms [1.6.1].
Nicotine	Smoking Cessation	Rare [1.4.2, 1.4.4]	Nausea, abdominal pain, dyspepsia [1.4.2]	Nicotine itself can affect the digestive system [1.4.3].
Scopolamine	Motion Sickness	Unlikely	Dry mouth, constipation [1.10.5]	As an anticholinergic, it decreases GI motility, making constipation far more likely than diarrhea [1.10.1].

Managing Diarrhea Caused by a Patch

If you suspect your medication patch is causing diarrhea, the first and most crucial step is to consult your healthcare provider. Do not stop using the medication on your own, as this can lead to other complications or withdrawal symptoms [1.3.3, 1.7.2].

Your doctor may suggest several strategies:

Monitoring and Evaluation: They will help determine if the patch is the true cause by reviewing the timing and severity of your symptoms [1.2.1].
Hydration and Diet: For mild cases, managing symptoms is key. Drink plenty of fluids to avoid dehydration [1.6.5]. A simple, bland diet (like the BRAT diet - bananas, rice, applesauce, toast) can be helpful [1.3.3].
Dose Adjustment: Sometimes, the side effect is dose-dependent. Your doctor might recommend a lower dose to see if the symptoms subside [1.3.4].
Switching Medication: If the side effect is persistent and intolerable, your doctor may switch you to a different formulation (e.g., from a patch to a gel or oral medication) or a different drug altogether [1.2.1].

Conclusion: A Balancing Act

Transdermal patches offer significant benefits, but they are not free from systemic side effects. The answer to 'Can the patch cause diarrhea?' is a clear yes for certain medications. While often less frequent than with oral drugs, the possibility exists because the medication circulates throughout the body. Understanding this potential side effect allows for better monitoring and communication with your healthcare provider. Always report new or bothersome symptoms to your doctor to ensure your treatment plan remains safe and effective.

For more detailed information on Fentanyl patches, you can visit the National Center for Biotechnology Information (NCBI).

Frequently Asked Questions

Not necessarily. Diarrhea is often a systemic side effect of the medication itself affecting your GI tract. An allergic reaction to a patch typically involves severe skin reactions like blistering, rash, or swelling, and may include difficulty breathing [1.7.5, 1.2.1]. However, you should report any new symptom to your doctor.

Rivastigmine (Exelon), used for dementia, and Buprenorphine, used for pain, are frequently reported to cause diarrhea, with incidence rates up to 19% for Rivastigmine and 10.3% for Buprenorphine [1.3.5, 1.9.1].

Yes, but it is considered a rare side effect for the transdermal patch. More common gastrointestinal side effects from the nicotine patch include nausea and abdominal pain [1.4.2, 1.4.4].

Report it to your doctor immediately. Diarrhea can occur when starting a fentanyl patch or when the dose is increased [1.5.1]. Your doctor needs to evaluate this symptom, especially since it can also be a sign of a more serious condition like serotonin syndrome [1.5.2].

It might reduce the severity. For some drugs like Rivastigmine, gastrointestinal side effects like diarrhea are reported less frequently with the patch compared to the oral capsules, but the risk is not eliminated [1.3.3].

Yes, like most hormonal birth control methods, the patch can cause a range of side effects as your body adjusts, including diarrhea, nausea, and abdominal pain [1.2.5].

First, consult your doctor. For mild cases, they may recommend staying hydrated and eating a bland diet [1.6.5, 1.3.3]. For persistent or severe diarrhea, they might adjust your dose or prescribe a different medication [1.2.1]. Do not take any anti-diarrhea medicine without talking to a pharmacist or doctor.