Approved indications
Xerese is FDA-approved for the early treatment of recurrent herpes labialis (cold sores) on the lips and around the mouth in adults and children 6 years and older, to reduce the chance that a cold sore becomes ulcerative and to shorten lesion healing time.

Off-label uses
It is not approved for genital herpes, eye infections, or non-herpetic skin problems, and there is little evidence supporting off-label use in these settings, so clinicians typically prefer standard oral antivirals or single-agent topical antivirals instead.

Efficacy expectations

• When started at the first sign of symptoms, about 4 in 10 patients can prevent their cold sore from progressing to an open ulcer, compared with about 1 in 4 using placebo cream.
• For patients who still develop sores, average healing time is shortened by roughly 1 to 1.5 days, and the overall lesion size and tenderness are reduced.
• Compared with topical acyclovir alone, the acyclovir–hydrocortisone combination provides a modest additional reduction in progression to ulceration and total lesion area, with a similar low rate of local side effects.

Typical dosing and how to apply
For adults and children 6 years and older, apply a thin layer of Xerese to cover the cold sore and a small margin of surrounding skin five times a day for 5 days, starting as early as possible at the first sign of tingling, burning, itching, or redness.

• Wash your hands before and after applying the cream, and gently apply enough to cover the entire affected area.
• Avoid rubbing vigorously, which can aggravate the lesion or spread the virus to nearby skin.
• Use only on the lips and skin around the mouth; do not use in the eyes, inside the mouth or nose, or on the genitals.
• Do not cover the area with airtight bandages and avoid applying other products (makeup, sunscreen, lip balm, or other creams) over the treated cold sore unless instructed.

Special dosing instructions
Use the cream at evenly spaced times during the day, do not use more often or for longer than 5 days unless your clinician tells you to, and do not share the tube with others.

Missed dose
If you miss a dose, apply it as soon as you remember, but skip it if it is almost time for your next application; do not apply extra cream to make up for a missed dose.

Overdose
Serious overdose from skin application is unlikely, but if a large amount is accidentally swallowed or if someone has unusual symptoms after overuse, contact a poison control center or seek medical care right away.

Common side effects

• Drying or flaking of the skin at the application site.
• Mild burning, stinging, or tingling right after application.
• Redness, swelling, or temporary changes in skin color where the cream is applied.

These effects are usually mild, begin soon after application, and in clinical studies each occurred in fewer than 1% of patients.

Serious or rare adverse effects

• Allergic reactions such as widespread rash, hives, severe itching, swelling of the face, lips, tongue, or throat, trouble breathing, or feeling faint.
• Severe or rapidly worsening burning, pain, or irritation at the application site.
• Signs of infection not improving or worsening, such as spreading redness, pus, or fever.

Stop using the cream and seek immediate medical attention if signs of a serious allergic reaction or severe skin reaction occur.

Warnings and precautions

• Age: Not approved for children younger than 6 years; use exactly as directed in older children and adults.
• Pregnancy and breastfeeding: Systemic absorption is very low, but safety data are limited; use only if the potential benefit justifies any possible risk after discussion with a healthcare professional.
• Immunocompromised patients: The benefit of Xerese has not been well studied; oral antivirals are often preferred for serious or frequent infections.
• Kidney or liver disease: No specific dose adjustment is recommended because systemic exposure is minimal, but other acyclovir-containing products taken by mouth or injection do require caution.
• Do not use in the eyes, inside the mouth or nose, or on the genitals, and do not cover the area with an occlusive dressing or apply cosmetics, sunscreen, or lip balm over the treated cold sore unless your clinician advises it.
• Do not use if you have had an allergic reaction to acyclovir, valacyclovir, hydrocortisone, or any ingredient in the cream.

Relative safety compared with other options
Because it is used on the skin and very little drug enters the bloodstream, Xerese has mainly local side effects and a low risk of systemic reactions, making its overall safety profile similar to other topical cold sore treatments and generally milder than that of oral antivirals.

Reporting side effects and safety updates
Side effects can be reported to the U.S. Food and Drug Administration through the MedWatch program (online or at 1-800-FDA-1088), where updated safety information and communications about prescription medicines are also available.

Drug and product interactions

• Because very little acyclovir or hydrocortisone enters the bloodstream from Xerese, it is not expected to interact significantly with most oral or injectable medicines.
• Avoid using other topical medicines, harsh cleansers, or irritants on the same area unless advised, as they can increase irritation or interfere with treatment.
• Do not apply cosmetics, lip balms, or sunscreens directly over the treated cold sore unless your healthcare professional says it is acceptable.
• There are no known interactions with foods or alcohol taken by mouth, though alcohol-containing topical products may sting or irritate the lesion.

Precautions and situations needing extra care

• Allergy to acyclovir, valacyclovir, hydrocortisone, or any component of the cream is a reason not to use Xerese.
• Use cautiously and under medical guidance if you are pregnant, breastfeeding, or have a weakened immune system, as clinical data in these groups are limited.
• Do not use on large areas of damaged skin, or on eyes, inside the mouth or nose, or on genitals; seek appropriate treatment for those sites instead.
• If the cold sore does not start to improve or has not healed within about 2 weeks, or if it worsens, contact a healthcare professional to rule out other conditions.

Monitoring
Routine blood tests or heart monitoring are not required with Xerese; monitoring generally consists of watching for side effects, signs of allergy, or lack of improvement and seeking medical advice if these occur.

Q: What does Xerese treat?
A: Xerese is used on the lips and skin around the mouth for the early treatment of recurrent cold sores (herpes labialis) to help prevent them from becoming open ulcers and to shorten healing time.

Q: How quickly should I start using Xerese?
A: Start applying Xerese as soon as you notice early symptoms such as tingling, burning, itching, or redness, because it works best when used at the very first sign of a cold sore.

Q: How often and for how long do I use Xerese?
A: Apply a thin layer to cover the cold sore and a small surrounding area five times a day for 5 days, unless your prescriber gives you different instructions.

Q: Can Xerese cure herpes or prevent future outbreaks?
A: No, Xerese does not cure the herpes virus or prevent future cold sores; it only helps the current outbreak heal faster and may keep some sores from progressing to open ulcers.

Q: Is Xerese safe for children?
A: Xerese is approved for adults and children 6 years of age and older when used exactly as directed; its safety and effectiveness are not known for children younger than 6.

Q: Can I use Xerese on genital herpes or in my eyes?
A: No, Xerese is only for cold sores on the lips and nearby skin and should not be used on the genitals, in the eyes, or inside the mouth or nose.

Storage
Store Xerese at controlled room temperature, about 68–77°F (20–25°C), with brief excursions allowed between 59–86°F (15–30°C); keep the tube tightly closed, in a cool, dry place away from heat, moisture, and direct sunlight, do not freeze, and keep out of reach of children and pets.

Disposal
When the cream is expired, no longer needed, or the tube is empty, dispose of it in household trash or through a community drug take-back program if available; do not flush it down the toilet or pour it into drains unless specifically instructed, and ask a pharmacist about local take-back or safe-disposal options.