What Is Sunlenca?

Sunlenca is the brand name for lenacapavir when it is used to treat HIV-1 infection. The U.S. Food and Drug Administration approved it in 2022 for heavily treatment-experienced adults with multidrug-resistant HIV-1 whose current antiretroviral regimen is failing. It is always used with one or more other antiretroviral medicines selected according to resistance testing, treatment history, tolerability, and safety.

Sunlenca is not a cure for HIV, is not approved as routine first-line treatment, and should never be used as the only active drug in an HIV regimen. Lenacapavir is also sold under the brand name Yeztugo for HIV pre-exposure prophylaxis, or PrEP, in eligible people without HIV. Although the active ingredient is the same, Sunlenca and Yeztugo have different indications and should not be casually swapped like identical coffee mugs.

How Lenacapavir Works

HIV surrounds its genetic material with a protein shell called a capsid. Lenacapavir binds where capsid protein subunits meet and interferes with several essential stages of the HIV life cycle. It disrupts the transport of viral genetic material into the cell nucleus, interferes with the assembly and release of new virus particles, and contributes to the formation of defective capsid cores.

Because this mechanism differs from those of nucleoside reverse transcriptase inhibitors, non-nucleoside reverse transcriptase inhibitors, protease inhibitors, and integrase inhibitors, lenacapavir may remain active against HIV that is resistant to several older drug classes. Resistance to lenacapavir itself can still develop, especially when it is effectively left working alone.

What Is Sunlenca Used For?

Sunlenca is intended for a narrow but important group: adults who have taken many HIV treatments and have multidrug-resistant HIV-1 that is not adequately controlled by their current combination. A specialist generally reviews resistance test results and constructs an optimized background regimen containing as many fully active companion drugs as possible.

It is not intended as a convenient twice-yearly replacement for a successful standard regimen. It also does not eliminate the need to take prescribed oral companion medicines. The injection may appear to be doing the glamorous long-acting work, but the rest of the regimen is still very much on the payroll.

Sunlenca Pictures and Appearance

Sunlenca treatment includes tablets and a liquid injection. The 300-mg tablet is beige, capsule-shaped, and film-coated. It is marked “GSI” on one side and “62L” on the other. The injectable solution is clear and yellow, contains no visible particles, and comes in single-dose glass vials containing 463.5 mg in 1.5 mL.

A complete 927-mg injection dose requires two separate 1.5-mL injections under the skin of the abdomen. Under the prescribing information revised in March 2026, the second injection should be administered at least four inches from the first injection site. Pictures found online should never be used as the sole method of identifying medication; confirm the package, imprint, dose, and pharmacy label.

Sunlenca Dosing Schedule

Sunlenca is started using one of two FDA-approved initiation schedules. The healthcare professional chooses the appropriate option. Tablets may be taken with or without food, while injections must be administered by a trained healthcare professional under the skin of the abdomen.

Initiation Option 1

Initiation Option 2

Maintenance Dosing

After either initiation option, the maintenance dose is 927 mg by subcutaneous injection every 26 weeks. The injection may ordinarily be administered within a window of two weeks before or two weeks after the scheduled date. It still consists of two injections, not one supersized shot.

What Happens If an Injection Will Be Missed?

For a planned delay of more than two weeks, the prescriber may use an oral bridge consisting of one 300-mg tablet every seven days for up to six months. Maintenance injections should resume within seven days after the final weekly tablet.

When more than 28 weeks have passed after the previous injection and no oral bridge was used, the patient should be reassessed, potentially including lenacapavir resistance testing. Treatment may need to be restarted using one of the full initiation schedules. Patients should call their HIV clinic rather than improvising a catch-up plan.

How Effective Is Sunlenca?

FDA approval was based primarily on the CAPELLA trial, which enrolled 72 heavily treatment-experienced adults with multidrug-resistant HIV-1. During the initial 14-day comparison period, 87.5% of participants who received lenacapavir had at least a 0.5-log reduction in HIV-1 RNA, compared with 16.7% of participants receiving placebo while both groups continued their failing regimens.

After Sunlenca was combined with an optimized background regimen, 81% of participants in the randomized cohort had HIV-1 RNA below 50 copies/mL at Week 26, and 83% did at Week 52. These were encouraging results in a population with limited treatment options, but the trial was small, and success depended on the strength of the entire combination rather than lenacapavir alone.

Common Sunlenca Side Effects

The most common adverse reactions in the CAPELLA trial were injection-site reactions and nausea. Injection-site reactions occurred in 65% of participants, while nausea was reported in 4%. Most adverse reactions were mild or moderate.

Injection-Site Reactions

Reported reactions included swelling, pain, redness, nodules, hardened areas, itching, leakage of medicine into surrounding tissue, and a mass at the injection site. Swelling occurred in 36% of trial participants, pain in 31%, redness in 31%, nodules in 25%, and induration or hardening in 15%.

Ordinary soreness, redness, or swelling may improve within several days. Nodules can last much longer because the long-acting medicine forms a depot under the skin. In the study, the median resolution time was 148 days for nodules and 70 days for induration. Many were noticeable by touch but not visible, meaning the abdomen might feel like it has acquired a tiny, unwanted paperweight even when it looks normal.

Potentially Serious Reactions

Improper injection into the skin rather than the subcutaneous tissue has been associated with ulceration and tissue necrosis. Injection-site necrosis has also been reported after approval. Contact the treating clinic promptly for severe or worsening pain, blistering, drainage, an open sore, spreading redness, fever, or skin color changes.

Important Sunlenca Warnings

Immune Reconstitution Inflammatory Syndrome

As combination antiretroviral treatment restores immune function, the immune system may react strongly to a previously hidden or partially treated infection. This is called immune reconstitution inflammatory syndrome, or IRIS. Examples include tuberculosis, cytomegalovirus, Pneumocystis pneumonia, and Mycobacterium avium infection. Autoimmune conditions can occasionally appear months after treatment begins. New fever, swollen glands, breathing problems, unusual weakness, vision changes, or other unexplained symptoms warrant medical evaluation.

The Long Pharmacologic “Tail”

Lenacapavir may remain in the body for 12 months or longer after the final injection. That is excellent when maintaining therapeutic concentrations, but inconvenient when a problem arises: the injection cannot simply be removed. Its effect on certain interacting medicines may remain clinically relevant for up to nine months after the last dose.

If Sunlenca is discontinued, an alternative fully suppressive HIV regimen should be started, when possible, no later than 28 weeks after the final injection. Otherwise, declining lenacapavir levels may leave HIV exposed to insufficient therapy and encourage resistance.

Resistance and Companion-Medicine Adherence

The 2026 prescribing information includes resistance findings through Week 156 of CAPELLA. Twenty-eight of 72 participants met criteria for resistance analysis, and 16 of those 28 developed lenacapavir resistance-associated capsid substitutions. Some cases occurred when the background regimen contained no fully active companion drug or when adherence to oral medicines was suboptimal.

In practical terms, a twice-yearly injection does not forgive repeated missed doses of the other HIV medications. Sunlenca must not become functional monotherapythe pharmaceutical version of sending one firefighter into a burning building and hoping for teamwork.

Sunlenca Drug Interactions

Lenacapavir is affected by CYP3A, P-glycoprotein, and UGT1A1 pathways. It is also a moderate CYP3A inhibitor and inhibits P-glycoprotein and BCRP. Consequently, other medicines can lower or raise lenacapavir concentrations, while lenacapavir can increase the concentrations of certain other drugs.

Medicines That Must Not Be Used With Sunlenca

Strong CYP3A inducers can sharply reduce lenacapavir exposure, causing treatment failure and resistance. Contraindicated examples include:

• Carbamazepine
• Phenytoin
• Rifampin
• St. John’s wort

Combinations Generally Not Recommended

Examples include oxcarbazepine, phenobarbital, rifabutin, rifapentine, efavirenz, nevirapine, tipranavir with ritonavir, atazanavir with ritonavir or cobicistat, and prolonged systemic dexamethasone. Drugs that simultaneously strongly inhibit CYP3A, P-glycoprotein, and UGT1A1 may raise lenacapavir exposure and are also not recommended.

Medicines Whose Levels May Increase

Sunlenca may increase exposure to digoxin, certain direct oral anticoagulants, lovastatin, simvastatin, fentanyl, oxycodone, tramadol, naloxegol, sildenafil, tadalafil, vardenafil, oral midazolam, and triazolam. Depending on the medicine, the prescriber may recommend a lower dose, laboratory monitoring, symptom monitoring, or a different treatment.

Elevated opioid concentrations can cause dangerous respiratory depression, while elevated statin levels can increase the risk of muscle injury. Increased sedative concentrations may cause excessive drowsiness or impaired breathing. Every prescriber and pharmacist should know that a patient is receiving Sunlenca, including during the nine months after the final injection. Keep a current list of prescriptions, nonprescription drugs, vitamins, supplements, and herbal products.

Pregnancy, Breastfeeding, Kidney Disease, and Liver Disease

Human pregnancy data remain insufficient to determine whether Sunlenca affects the risk of miscarriage or birth defects. An Antiretroviral Pregnancy Registry collects pregnancy outcomes following exposure. People who are pregnant or planning pregnancy should review the benefits, uncertainties, companion medicines, and long duration of drug exposure with an HIV specialist.

It is not known whether lenacapavir is present in human milk or affects a breastfed infant. Infant-feeding decisions should be individualized with an HIV care team because considerations include maternal viral suppression, possible drug exposure, HIV transmission, and infant follow-up.

No dosage adjustment is recommended for mild, moderate, or severe renal impairment when estimated creatinine clearance is at least 15 mL per minute, although end-stage renal disease has not been studied. No adjustment is recommended for mild or moderate liver impairment; severe hepatic impairment has not been studied. Sunlenca’s safety and effectiveness for HIV treatment have not been established in pediatric patients.

Practical Experience: What Treatment With Sunlenca May Feel Like

The following is an educational composite of practical issues patients may encounter, not a quotation or testimonial from one individual.

The Sunlenca experience often begins long before the first injection. A specialist may review years of treatment history, old resistance tests, medication intolerances, insurance requirements, and potential drug interactions. Patients who have lived with HIV for decades can arrive with a medication history long enough to qualify as light airport reading. The goal is not merely to add Sunlenca; it is to build a complete regimen in which the new injection has reliable partners.

Initiation day may involve medication counseling, two abdominal injections, oral tablets, and scheduling the next doses before leaving the clinic. The injections are placed under the skin rather than into muscle. People may feel pressure, burning, or stinging during administration, followed by tenderness or swelling. Wearing loose clothing and avoiding waistbands that press directly on the injection sites may make the trip home more comfortable. Patients should follow their clinic’s advice before using ice, heat, pain relievers, or topical products.

During the first several days, ordinary injection reactions may behave like a bruise: noticeable when bending, stretching, sleeping on the stomach, or fastening a seat belt. Redness and soreness frequently settle, but a firm lump may remain. Because nodules can persist for months, their continued presence does not automatically mean the medicine is failing or that something is dangerously wrong. The useful approach is to monitor the area and report worsening pain, expanding redness, drainage, skin breakdown, or other changes rather than repeatedly squeezing the lump like an elevator button.

After the injection-site symptoms become less interesting, the biggest adjustment may be psychological. A six-month interval can feel liberating, particularly for someone exhausted by treatment changes and resistance. It can also create false confidence. Sunlenca does not replace companion antiretroviral drugs, viral-load monitoring, laboratory testing, refill planning, or communication with the care team. Patients may benefit from linking oral doses to a stable daily activity and using a pillbox, pharmacy synchronization, or phone reminders.

The calendar becomes part of the treatment plan. Many clinics schedule the next injection immediately and send reminders several weeks ahead. Patients can also create personal reminders one month, two weeks, and several days before the appointment. Travel, relocation, job changes, insurance disruptions, and family emergencies should be discussed early. A planned oral bridge may be possible, but only when arranged by the prescriber. Waiting until Week 29 to announce a three-month cruise is not ideal logistical theater.

Every new healthcare encounter should include a reminder that lenacapavir is still in the body. This matters when another clinician prescribes seizure medicine, tuberculosis treatment, steroids, sedatives, opioids, anticoagulants, cholesterol medicine, or erectile-dysfunction treatment. Even an herbal product such as St. John’s wort can create a major problem. A wallet medication card or updated list on a phone can prevent accidental interactions.

Follow-up viral-load results may be emotionally significant for people who have experienced repeated regimen failures. Declining HIV RNA and improving immune markers can provide relief, but an unexpected rebound requires rapid attention rather than blame. The team may assess adherence, interactions, resistance, medication access, and the activity of the companion regimen. Sunlenca’s long action can be a major advantage, but the best experience comes from treating the injection, oral drugs, laboratory monitoring, and appointments as one coordinated system.

Final Takeaway

Sunlenca gives heavily treatment-experienced adults with multidrug-resistant HIV-1 a valuable treatment option with maintenance injections given every six months. Its unusual capsid-targeting mechanism and long duration make it different from traditional antiretroviral drugs, but “long-acting” does not mean “low-maintenance.” Success depends on an active companion regimen, reliable attendance at injection visits, careful management of interactions, and rapid attention to viral rebound or serious injection-site symptoms.

Before starting Sunlenca, patients should understand both the freedom and the fine print: the medicine can remain in the body for a year or longer, influence interacting drugs for months, and permit resistance if the full regimen is not followed. With experienced HIV care and good planning, twice-yearly treatment can be a powerful tool rather than merely an impressive calendar trick.