Hovilpri (pritelivir) is an antiviral tablet used to treat herpes simplex virus (HSV) sores in adults with weakened immune systems when other medicines haven't worked.
Like all medicines, Hovilpri can cause side effects and may interact with other medicines, supplements, or alcohol.
Keep reading to learn about the possible side effects of Hovilpri, how to manage them, and which medicines may interact with Hovilpri.
This article does not include all possible side effects or interactions. Tell your health care provider about any symptoms that concern you or do not improve.
Hovilpri Side Effects
Common side effects
Headache was the only side effect reported by more than 5% of people who took Hovilpri in the main clinical study. It happened in 6% of people who took Hovilpri and 4% of people who got other treatments.
Overall, side effects were reported in 22% of people who took Hovilpri, compared with 54% of people who got the other treatments (IV foscarnet, IV or topical cidofovir, or imiquimod cream). About 2% of people stopped Hovilpri because of side effects, compared with 20% in the comparison group.
Your results may differ from what was seen in clinical studies.
Other effects seen in the study
Some people had higher-than-normal liver enzymes on blood tests. Liver enzymes are proteins that can rise in the blood when the liver is stressed or damaged. One person stopped taking Hovilpri because of high liver enzymes.
How to Manage Hovilpri Side Effects
While not a complete guide, the following tips can help you prevent or manage the side effects of Hovilpri.
Headache
Headache is the most commonly reported side effect of Hovilpri. Symptoms may include head pain or pressure.
To help manage headaches:
- Rest in a quiet, dark room if needed.
- Drink enough fluids throughout the day.
- Try relaxation techniques, such as deep breathing.
- Maintain a regular sleep schedule.
- Minimize stress.
- Eat regular meals or snacks.
An over-the-counter (OTC) pain reliever may help ease your headache, but check with your pharmacist or other health care provider first to make sure it is safe for you.
Tell your health care provider if your headaches are severe or don't go away. Don't stop taking Hovilpri on your own. Your sores need to heal, and stopping the medicine early may keep that from happening.
High liver enzymes
In the main study of Hovilpri, some blood tests showed higher liver enzymes in people who took the medicine. The enzyme called alanine aminotransferase (ALT) rose to at least 2.5 times the upper limit of normal in 8% of people who took Hovilpri (4 out of 51), compared with 2% (1 out of 50) in the comparison group. The enzyme called aspartate aminotransferase (AST) rose by that much in 6% (3 out of 51) of people who took Hovilpri and 4% (2 out of 50) in the comparison group.
Higher liver enzymes don't always cause symptoms. Tell your health care provider right away if you notice signs of a liver problem, such as:
- Yellowing of your skin or the whites of your eyes
- Dark urine or pale stools
- Pain in the upper right part of your belly
- Nausea or vomiting that doesn't go away
- Unusual tiredness or loss of appetite
Tell your health care provider if you have liver problems or take other medicines that can affect your liver. Keep all appointments with your health care provider, including for blood tests. Your provider may check your liver with blood tests. If your liver enzymes rise, your provider may decide whether you should keep taking Hovilpri. Don't stop it on your own.
If you have symptoms that feel serious or life-threatening, seek medical care right away.
Hovilpri Interactions
Hovilpri can interact with other medicines. An interaction happens when a substance changes how a medicine works or affects the body. Some interactions can make Hovilpri not work as well. Other interactions can raise the levels of other medicines in your body.
Hovilpri is absorbed best when your stomach acid is at its normal level. Medicines that lower stomach acid levels may reduce how much Hovilpri gets into your blood. This may make Hovilpri work less well. It could also allow the virus to become resistant to Hovilpri, which means the medicine may stop working against it.
Hovilpri can also block a protein in your body called breast cancer resistance protein (BCRP). This protein helps move some medicines out of your cells. When it's blocked, levels of those medicines can rise.
This is not a full list of interactions, but the following are important to know about while taking Hovilpri.
Certain stomach acid reducer medicines (proton pump inhibitors)
Proton pump inhibitors (PPIs) are used to treat heartburn, acid reflux, and ulcers. Some PPIs can lower Hovilpri levels in your body. In one study, people who took esomeprazole had about 59% less total Hovilpri in their blood over time than people who didn't take it.
Avoid taking these PPIs with Hovilpri:
- Esomeprazole (Nexium)
- Omeprazole (Prilosec) or lansoprazole (Prevacid) at daily doses above 20 mg
- Pantoprazole (Protonix) at daily doses above 40 mg
- Rabeprazole (Aciphex)
Lansoprazole, omeprazole, and pantoprazole are okay to be taken with Hovilpri at or below the doses listed above. At those lower doses, they don't lower Hovilpri levels enough to matter.
Some PPIs are sold without a prescription, so check with your pharmacist before you take one. If you already take a PPI, talk with your health care provider before you start Hovilpri. Your provider may recommend a different option or a lower PPI dose. Don't change or stop your PPI on your own.
H2 blockers
H2 blockers (also called H2-receptor antagonists) lower your stomach acid levels and are used for heartburn and ulcers. Examples include cimetidine (Tagamet), famotidine (Pepcid, Zantac), and nizatidine (Axid).
You can take an H2 blocker with Hovilpri, but timing matters. Take Hovilpri at least two hours before or at least 12 hours after you take an H2 blocker. Because Hovilpri is taken every day, ask your pharmacist to help you build a schedule that works if you also need to take an H2 blocker.
Antacids
Antacids are used for quick relief of heartburn and upset stomach. Examples include products that contain calcium carbonate or aluminum hydroxide and magnesium hydroxide.
Take Hovilpri at least two hours before or at least two hours after you take an antacid.
Medicines moved by BCRP
Hovilpri can raise the levels of some medicines that rely on the BCRP protein to leave your cells. This may raise your risk of side effects from those medicines.
Examples include:
- Rosuvastatin (Crestor), a cholesterol medicine
- Sulfasalazine (Azulfidine), a medicine used for conditions such as ulcerative colitis and rheumatoid arthritis
Tell your pharmacist and other health care providers about all the medicines you take before you start Hovilpri. They can help decide whether you need a different option or any extra monitoring. Don't change the dose of your other medicines on your own.
Reducing Your Risk of Side Effects and Interactions
You can help reduce your risk of side effects and interactions by taking Hovilpri exactly as prescribed and following all instructions from your health care provider.
Helpful tips include:
- Tell your pharmacist and other health care providers about all prescription medicines, OTC medicines, vitamins, herbs, and other supplements you use, including anything for heartburn, acid reflux, or stomach acid.
- Ask your health care provider before you start or stop any medicine, vitamin, or supplement.
- Keep all recommended lab test appointments, including any blood tests to check your liver.
- Report new or worsening symptoms to your health care provider.
Your health care provider can review your treatment plan and make changes if needed to help keep this medicine safe for you. Don't change or stop treatment on your own.
