What It Means When You Have Diarrhea After Taking Medicine

Medications can come with a wide range of side effects. Depending on what kinds of medicines you take, you might experience headaches, drowsiness, dry mouth, nausea, or more. Some medications, in particular, can cause our gastrointestinal tract a great deal of grief. For many, this comes in the form of diarrhea. According to a 2000 scientific review published in the scientific journal Drug Safety, diarrhea is responsible for approximately 7% of all negative drug side effects and has been associated with over 700 different medications.

There are two different kinds of diarrhea a person may experience in connection with their medicines: acute diarrhea or chronic diarrhea. Acute cases of diarrhea are usually short-lived and appear at the onset of treatment. Chronic cases, on the other hand, may persist for upwards of four weeks and may emerge even after a person has been taking the medication for quite some time. Either way, nobody likes dealing with "the runs." While most cases of medication-induced diarrhea are temporary and do not require medical treatment, there are instances in which it can potentially be a sign of something more serious, cautions Alberta Health.

Medication-related diarrhea and possible infection

Antacids, antibiotics, antidepressants, NSAIDs, chemotherapy drugs, metformin, and even certain supplements are just a few of the many different medications that can prompt a bout of diarrhea (via WebMD). For example, chemotherapy drugs can throw off the functioning of the small intestine, while antacids are made up of calcium and magnesium, all of which can have you sprinting for the bathroom.

Many people are particularly familiar with antibiotic-related tummy trouble, as these medications can disrupt your carefully balanced microbiome. Roughly 5% to 30% of people who take antibiotics experience either acute diarrhea or chronic diarrhea even after they've finished taking the round of medication as prescribed, according to 2002 research published in the British Medical Journal (BMJ). In some cases, diarrhea that occurs after taking antibiotics may indicate a Clostridium difficile infection. This bacteria accounts for as much as one-quarter of antibiotic-related diarrhea cases. Once evidence of the pathogen has been identified in the patient's stool, the infection can be treated with medication, although relapse is possible. While there is some evidence to suggest probiotics may be effective in staving off antibiotic-related diarrhea, the research is not conclusive.

When to seek medical help

In more serious cases, if you experience diarrhea that strikes immediately after taking medicine, it could mean that you're having a potentially toxic reaction to the drug, explains Alberta Health. This is sometimes seen in relation to a heart failure medication known as digoxin or the mental health treatment drug lithium.

In cases of lithium toxicity, diarrhea is usually accompanied by additional symptoms, including bloating, stomach pain, nausea, or vomiting that emerges within 60 minutes of having taken too much of the drug (via Cleveland Clinic). Neurological symptoms may occur soon after, such as confusion, balance problems, tremors, slurred speech, seizures, or more. A person exhibiting these signs will need immediate medical intervention. For those taking digoxin, call your physician promptly if you experience diarrhea after taking the medication (via MedlinePlus). The same is true if you experience vomiting, an upset stomach, loss of appetite, swelling in the extremities, abnormal weight gain, or trouble breathing. 

Regardless of what medicine you may be taking, if you notice the development of diarrhea, always speak with your doctor. Changes to the dosage or type of medication may be recommended.