Pre-exposure prophylaxis (PrEP) is a medication taken by HIV-negative individuals to prevent HIV infection. It is an effective method to reduce the risk of acquiring the virus. Many people considering or starting PrEP have questions about potential side effects as their bodies adjust to the medication.
Diarrhea as a Common Initial Side Effect
Diarrhea is a common initial side effect for some individuals starting PrEP. It is typically mild and temporary, often resolving as the body adapts to the medication. Approximately 1% to 10% of new users may experience diarrhea in the first few weeks or month of starting PrEP. This symptom usually subsides within a few days to a couple of weeks, allowing most individuals to continue their medication without ongoing discomfort.
Why PrEP Can Cause Diarrhea
The active ingredients in PrEP, such as emtricitabine and tenofovir disoproxil fumarate, or emtricitabine and tenofovir alafenamide, can lead to gastrointestinal upset. These medications are nucleoside/nucleotide reverse transcriptase inhibitors that interfere with HIV’s ability to replicate. As the body adjusts to these compounds, it can manifest as digestive disturbances like diarrhea.
Managing Diarrhea and Seeking Medical Guidance
For mild diarrhea, several strategies can help manage symptoms. Taking PrEP with food can often reduce gastrointestinal discomfort. Staying well-hydrated by drinking plenty of fluids is important to prevent dehydration. Avoiding irritating foods like spicy or greasy items and opting for bland, easy-to-digest foods such as bananas, rice, applesauce, and toast (BRAT diet) can also be beneficial. Over-the-counter anti-diarrheal medications may offer relief, but consult a healthcare provider before using them.
Seek medical guidance if diarrhea becomes severe or persistent. Contact a healthcare professional if diarrhea lasts longer than two days, if there are signs of dehydration (excessive thirst, dry mouth, dizziness, dark urine), or if you experience a fever. Other concerning symptoms include severe abdominal pain, bloody or black stools, or if diarrhea significantly impacts your daily life. Do not stop taking PrEP without first consulting your healthcare provider, as this could compromise its effectiveness in preventing HIV.
Other Common Initial PrEP Side Effects
Beyond diarrhea, new PrEP users might experience other common, generally mild, and temporary initial side effects. Nausea is frequently reported, often occurring alongside stomach discomfort. Some individuals may also notice headaches or fatigue when first starting the medication. Bloating, dizziness, and minor skin irritations like rashes are also possible, though less common. These symptoms typically resolve within the first few weeks as the body becomes accustomed to the medication.