Continuing Education Activity

Emtricitabine is a nucleoside reverse transcriptase inhibitor widely used in combination antiretroviral therapy for the treatment of HIV-1 and HIV-2 infections, management of hepatitis B virus, and as part of pre-exposure prophylaxis to prevent HIV acquisition. This activity introduces clinicians to emtricitabine’s pharmacology, mechanism of action, safety profile, monitoring requirements, and drug interactions, highlighting its FDA-approved uses as well as relevant off-label considerations. Special attention focuses on its role in post-exposure prophylaxis, use during pregnancy, and in patients with coexisting conditions such as hepatitis C, providing a comprehensive foundation for evidence-based patient care.

This activity explores the integration of emtricitabine in HIV prevention and treatment, emphasizing the vital role of an interprofessional healthcare team in optimizing outcomes. Through focused discussions on patient risk assessment, dosing strategies, adherence counseling, and laboratory monitoring, the activity enhances clinician competence in individualizing therapy and minimizing adverse effects. By fostering interprofessional collaboration, promoting shared decision-making, and strengthening patient education, healthcare providers improve the effectiveness of emtricitabine-based regimens and advance the quality of care for individuals living with or at risk for HIV infection.

Objectives:

• Identify the mechanism of action and pharmacologic profile of emtricitabine in HIV treatment and prevention.
• Implement patient education strategies on proper use, adherence, and potential adverse effects.
• Assess patients for contraindications, comorbidities, and potential drug interactions before initiating emtricitabine therapy.
• Collaborate with interprofessional healthcare teams to coordinate comprehensive care for individuals receiving emtricitabine therapy while optimizing adherence and minimizing the risk of adverse effects.

Indications

Antiretroviral therapy (ART) has become the mainstay of treatment for patients living with HIV.

FDA-Approved Indications

Emtricitabine is approved by the US Food and Drug Administration (FDA) for HIV treatment but not for hepatitis B virus (HBV) treatment.[1] A study showed that 200 mg emtricitabine helped patients achieve a lower HBV DNA load and normalize their alanine aminotransferase (ALT) levels.[2] For pregnant women with concurrent HIV infection, ART should commence as soon as possible. ART options for pregnancy include the nucleoside reverse transcriptase inhibitor (NRTI) emtricitabine, as well as abacavir, lamivudine, and tenofovir. Early initiation of ART during pregnancy reduces the risk of transmitting HIV to the infant. Emtricitabine is classified as an FDA pregnancy category B drug and is not associated with teratogenicity or congenital abnormalities.[3] Emtricitabine is also safe for use in patients coinfected with HIV and the hepatitis C virus (HCV), as it has minimal interactions with HCV medications.[4]

The FDA-approved combination drug containing emtricitabine and tenofovir is used as pre-exposure prophylaxis (PrEP) to prevent HIV infection.[5][6][7] PrEP is indicated for individuals at significant risk of HIV infection, including:

• Individuals who have sexual partners who are HIV-positive or of unknown HIV status.
• Individuals who are not in a mutually monogamous relationship.
• Individuals who have had a sexually transmitted infection within the past 6 months.
• Individuals who use condoms inconsistently.
• Individuals who engage in other high-risk sexual behaviors.
• Individuals who use intravenous (IV) drugs or have entered a drug rehabilitation program within the previous 6 months.

The PROUD study evaluated the effectiveness of PrEP in HIV-negative men in clinics across England in 2013. The study demonstrated an 86% reduction in HIV incidence among participants receiving PrEP compared with men who have sex with men attending the same clinics, where the HIV rate was 7 times higher based on 2012 data.[8][9]

Another indication for emtricitabine is its use as post-exposure prophylaxis (PEP) following possible exposure to HIV infection. Potential routes of HIV transmission include receptive and insertive anal intercourse, receptive and insertive vaginal intercourse, blood transfusion, needlestick injury, sharing needles among individuals who inject drugs, and mucous membrane exposure. PEP administration should occur within 72 hours of possible exposure, with a recommended duration of 28 days. PEP therapy is similar to HIV therapy and includes the use of 2 NRTIs with an additional HIV medication from a different category. The combination pill containing emtricitabine and tenofovir is a common therapeutic choice as part of PEP therapy due to fewer adverse effects.[10][11] 

According to the 2025 Centers for Disease Control and Prevention (CDC) guidelines, HIV nonoccupational PEP (nPEP) should be initiated as early as possible, ideally within a few hours and no later than 72 hours after potential exposure, as delayed initiation markedly decreases its effectiveness. A comprehensive clinical evaluation should be performed before initiating therapy to assess comorbidities, current medications, and possible allergies. The recommended duration of nPEP is 28 days, and adherence to the entire course is essential. Preferred regimens include emtricitabine in combination with tenofovir alafenamide or tenofovir disoproxil fumarate, along with an integrase inhibitor such as dolutegravir or bictegravir.[12] Lamivudine may be used as an alternative to emtricitabine when necessary.[11]

Off-Label Uses

The NRTI emtricitabine is used in combination with other ART in the treatment of HIV-1, HIV-2, and HBV.[3] A study showed that 200 mg emtricitabine helped patients achieve a lower HBV DNA load and normalize their ALT levels.[2] For pregnant women with concurrent HIV infection, ART should commence as soon as possible. ART options for pregnancy include the NRTI emtricitabine, along with abacavir, lamivudine, and tenofovir. Early administration of ART in pregnancy reduces the risk of transmitting HIV to the infant.[4] Emtricitabine is classified as an FDA pregnancy category B drug and is not associated with teratogenicity or congenital abnormalities.[3] Emtricitabine is also safe for use in patients coinfected with concurrent HIV and HCV infection, as it has minimal interactions with HCV medications.[4]

Mechanism of Action

Emtricitabine is a cytosine analog that functions as an NRTI, and its chemical name is 5-fluoro-1-[2R,5S)-2-(hydroxymethyl)-[1,3]oxathiolane-5-yl]cytosine (FTC).[2] Emtricitabine shares a structural similarity with lamivudine.[3] Similar to other NRTIs, emtricitabine is administered as a prodrug and must enter the host cell, where it undergoes phosphorylation before imparting its antiviral effects.[13] Once inside the cell, emtricitabine is phosphorylated to the active triphosphate form, emtricitabine 5’-triphosphate, which incorporates into the HIV reverse transcriptase of the viral DNA, thereby preventing future HIV DNA synthesis.[3] Emtricitabine inhibits the formation of a 3’-5’-phosphodiester bond between the drug molecule and the 5’-nucleoside triphosphates of the HIV DNA chain, resulting in premature termination of the growing DNA chain.[13]

In general, NRTIs work by blocking the activity of HIV from using reverse transcriptase, thereby preventing the conversion of viral RNA into DNA. Without reverse transcriptase, HIV replication within host cells is halted. Inhibition of reverse transcriptase activity ultimately leads to a reduction in viral load and an increase in CD4+ T-cell counts.[9] Resistance to emtricitabine can develop if viral suppression is incomplete, reducing the drug’s effectiveness. The M184V/I mutation is the primary mechanism associated with emtricitabine resistance.[14]

Pharmacokinetics

Absorption: Emtricitabine is rapidly and extensively absorbed following oral administration, with maximum plasma concentrations typically attained within 1 to 2 hours post-dose. The mean absolute bioavailability of the capsule formulation is approximately 93%, while that of the oral solution is about 75%. The relative bioavailability of the oral solution is estimated to be 80% compared with the capsule formulation.

Administration with food has no clinically significant effect on systemic exposure, as measured by the area under the concentration-time curve (AUC). However, coadministration of emtricitabine capsules with a high-fat meal (~1000 kcal) results in a reduction in peak plasma concentration (Cmax) by approximately 29% without affecting AUC. In contrast, administration of a 200 mg oral solution with either high-fat or low-fat meals does not alter either AUC or Cmax. Therefore, emtricitabine may be administered with or without food.

Distribution: Emtricitabine demonstrates low binding to human plasma proteins (<4%). At peak plasma concentrations, the mean plasma-to–whole blood concentration ratio is approximately 1.0, suggesting an even distribution between plasma and blood cells. The mean semen-to-plasma concentration ratio is approximately 4.0, indicating preferential distribution into seminal fluid.

Metabolism: Emtricitabine undergoes limited biotransformation in humans. The principal metabolic pathways include oxidation of the thiol group (approximately 9% of the administered dose) and glucuronidation (approximately 4% of the dose). The unchanged parent compound is the major circulating form in plasma.

Excretion: The terminal elimination half-life of emtricitabine is approximately 10 hours. Renal clearance exceeds the estimated creatinine clearance, indicating that elimination involves both glomerular filtration and active tubular secretion. Approximately 86% of an administered dose is excreted in the urine and 14% in the feces, confirming that renal excretion is the primary route.[3]

Administration

Available Dosage Forms and Strengths

Emtricitabine is available as 200 mg hard gelatin capsules and as a clear, orange-colored oral solution containing 10 mg/mL.

Adult Dosage

Emtricitabine is typically administered orally once a day in combination with other ART.[15] ART should be initiated as soon as possible after an accurate diagnosis of HIV infection, ideally within the first 14 days.[16] The World Health Organization (WHO) recommends initiating ART within 7 days after diagnosis to decrease viral load.[4] 

A 3-drug regimen is generally recommended for the initial treatment of HIV, consisting of 2 NRTIs and an integrase inhibitor. The recommended initial regimens include combinations such as tenofovir, emtricitabine, and bictegravir or tenofovir, emtricitabine, and dolutegravir. In the setting of opportunistic infections, ART should commence within the first 2 weeks. The detection of malignancy in HIV-infected individuals constitutes immediate ART therapy.[4]

Emtricitabine has been studied at doses of 25 mg twice daily, 100 mg once or twice daily, and 200 mg once or twice daily.[3] All doses studied led to a reduction in HIV viral load, with higher doses leading to more significant reductions.[3] Emtricitabine, when combined with other ART, such as didanosine and efavirenz, led to an even more significant decrease in HIV viral loads and an increased CD4+ T-cell count.[3] Studies estimate that a 95% adherence to ART is needed to achieve undetectable viral loads and prevent the risk of developing drug-resistant HIV.[17] Proper adherence requires patients to take their HIV regimens every day precisely as prescribed by their physician.

Emtricitabine (200 mg) and tenofovir (300 mg) used as PrEP are prescribed as a once-daily oral tablet.[18]

Specific Patient Populations

Hepatic impairment: No specific dose adjustment is recommended for patients with hepatic impairment. However, caution is advised in older patients, as clinical trials did not include a sufficient number of older adults to fully assess potential differences in drug response.

Renal impairment: Dose adjustment is recommended in patients with creatinine clearance below 50 mL/min or for those requiring dialysis, due to the primarily renal excretion of emtricitabine.

Pregnancy considerations: A pregnancy exposure registry is available to monitor outcomes in patients exposed to emtricitabine during pregnancy. Healthcare providers are encouraged to enroll patients by calling 1-800-258-4263. Data from over 2700 first-trimester exposures have not shown an increased risk of major birth defects compared with the US background rate (2.4% vs 2.7%). Animal studies have also demonstrated no adverse developmental effects at exposures equal to or greater than 60 times the recommended human dose.

Breastfeeding considerations: Emtricitabine is excreted in breast milk and has been studied in breastfeeding individuals. In HIV-positive mothers with sustained viral suppression on ART, the risk of HIV transmission via breastfeeding is less than 1%. Such individuals may be supported if they choose to breastfeed, provided there is close monitoring and clinical guidance. If viral load is not suppressed, the use of formula or donor milk is recommended.

In mothers infected with HBV, breastfeeding is considered safe if the infant receives hepatitis B immune globulin and the hepatitis B vaccine at birth. However, there is concern that an exclusively breastfed infant may receive about 2% of the proposed infant dose of emtricitabine, thereby potentially achieving serum concentrations that might result in viral resistance.[19] Due to the combined risks of postnatal HIV transmission, resistance development, and adverse effects in infants, product labeling advises against breastfeeding for mothers taking emtricitabine.

Pediatric patients: Safety and efficacy of emtricitabine have been demonstrated in patients aged between 3 months and 21 years based on clinical trial data. Pharmacokinetic studies have also been conducted in neonates; however, according to the product labeling, the efficacy of the drug for the prevention or treatment of HIV-1 infection in neonates has not been established.

Older patients: Data on emtricitabine use in patients aged 65 or older are limited. Caution is advised when prescribing to this population due to the higher likelihood of decreased organ function and polypharmacy. Studies indicate that exposure to emtricitabine and other antiretroviral drugs may increase with age.[20]

Adverse Effects

The adverse effects of emtricitabine are similar to those of other NRTIs. They may include headache, muscle weakness, arthralgia, fatigue, fever, abdominal pain, nausea, vomiting, diarrhea, depression, anxiety, insomnia, rhinitis, cough, and pharyngitis. More specifically, emtricitabine has been associated with skin discoloration. This dermatologic effect typically presents as hyperpigmentation of the palms and soles, occurring more frequently among African American patients. Less commonly, skin discoloration may also appear on the tongue, arms, lips, and nail beds. Emtricitabine has not been associated with any serious adverse events.[3][15]

Emtricitabine combined with tenofovir, when used as PrEP, is considered safe for short-term use of approximately 2 to 3 years. The most commonly reported adverse effects associated with this combination include gastrointestinal symptoms, headache, nausea, and depression. This combination has been linked to decreased creatinine clearance, which typically improves after discontinuation of the drug. PrEP may initially cause a decline in glomerular filtration rate (GFR), but this decline becomes more gradual with prolonged use of PrEP. Although PrEP has not been associated with severe renal dysfunction, a decreased GFR is more commonly observed in patients older than 40. This combination has also been correlated with a decrease in bone mineral density, which returns to normal levels after discontinuation of the drug. Current evidence does not suggest that this decline in bone mineral density increases the risk of fractures.[21][22][23]

Drug-Drug Interactions

According to the product labeling, emtricitabine does not inhibit metabolism mediated by human cytochrome P450 isoenzymes, including CYP2D6 and CYP3A4, at concentrations up to 14 times higher than those observed in humans. Emtricitabine also does not inhibit uridine 5'-diphospho-glucuronosyltransferase, the primary enzyme responsible for glucuronidation. Based on these in vitro findings and the established elimination pathways of emtricitabine, the potential for clinically relevant drug interactions mediated by cytochrome P450 inhibition is considered low. Nevertheless, caution is advised when emtricitabine is administered concomitantly with nephrotoxic medications, as it is primarily eliminated via the renal system. Healthcare professionals should also assess potential drug interactions associated with emtricitabine within fixed-dose regimens used in ART with other drugs.

Contraindications

Patients with an allergy to any constituent of emtricitabine should avoid taking this drug. The combination of emtricitabine and tenofovir for PrEP is contraindicated as monotherapy in individuals with confirmed HIV infection, as it can promote the development of antiretroviral resistance. Emtricitabine alone has not demonstrated any significant drug interactions.[3] PrEP therapy is contraindicated in patients who have impaired renal function with a creatinine clearance of 60 mL/min.[9] Concomitant use of PrEP with high-dose nonsteroidal anti-inflammatory drugs, acyclovir, valacyclovir, cidofovir, or aminoglycosides is also contraindicated due to the increased risk of nephrotoxicity.[9]

Box Warning: Posttreatment Acute Exacerbation of Hepatitis B

All patients should be screened for chronic HBV infection before or at the initiation of emtricitabine therapy. Severe acute exacerbations of HBV, including cases of hepatic decompensation and liver failure, have been reported in patients coinfected with HIV-1 and HBV following discontinuation of emtricitabine. Patients with HIV-1 and HBV coinfection who discontinue emtricitabine should undergo careful clinical and laboratory monitoring for several months after therapy cessation. In patients with advanced hepatic disease or cirrhosis, alternative anti-HBV therapy should be initiated, as hepatic flares may lead to decompensation or liver failure.

Warnings and Precautions

Immune reconstitution inflammatory syndrome: In patients receiving combination ART that includes emtricitabine, restoration of immune function may trigger an inflammatory response to underlying opportunistic infections such as Mycobacterium avium complex, cytomegalovirus, Pneumocystis jirovecii pneumonia, or tuberculosis. Autoimmune disorders, including Graves’ disease, polymyositis, and Guillain-Barré syndrome, have also been reported and may occur several months after treatment initiation.

Lactic acidosis and hepatic steatosis: The use of nucleoside analogues, including emtricitabine, has been associated with lactic acidosis and severe hepatomegaly with steatosis, including fatal cases. Therapy should be stopped if clinical or laboratory findings suggest lactic acidosis or hepatotoxicity, regardless of transaminase levels.

Monitoring

As outlined in the warning, patients should be tested for HBV infection before initiating therapy. During ART, regular monitoring of HIV-1 viral load and CD4+ T-cell count is essential to evaluate treatment response. Renal function should be assessed by measuring serum creatinine levels.[24] Given the risk of hepatic steatosis, liver function tests, including ALT, aspartate aminotransferase, and total bilirubin, should be monitored periodically to assess the potential for hepatotoxicity.[25] The risk of lactic acidosis may increase, especially when using older tenofovir-based regimens.[26]

Toxicity

Signs and Symptoms of Overdose

Emtricitabine, along with the other drugs in the NRTI category, can interact with mitochondrial DNA polymerase, leading to myopathy and neuropathy. This mitochondrial toxicity is also associated with hepatic steatosis and lactic acidosis. Emtricitabine has not been shown to have any adverse effects on the mitochondrial function of developing fetuses and is not known to be teratogenic. There is no evidence that emtricitabine affects the fertility rates of women taking the drug.[3] Acute intentional overdose involving emtricitabine–tenofovir has been reported to cause severe lactic acidosis requiring intubation for airway protection.[26]

Management of Overdose

If an overdose occurs, the patient should be closely monitored for signs of toxicity, and standard supportive care should be provided as needed. Hemodialysis can remove a portion of the emtricitabine dose during a 3-hour session. The effectiveness of emtricitabine removal by peritoneal dialysis has not been established.

Enhancing Healthcare Team Outcomes

HIV prevention and treatment require an integrated, interprofessional healthcare team consisting of primary care physicians, physician associates, nurse practitioners, specialty physicians, nurses, office staff, pharmacists, and laboratory personnel. Effective HIV prevention begins with health education on safer sex practices provided by the primary care physician.

Primary care providers should maintain a nonjudgmental approach and be skilled in obtaining a detailed sexual history using open-ended questions, as well as assessing social history, including alcohol and drug use.[27] At each patient visit to the primary care clinic, a risk assessment for HIV acquisition should be performed.[4] In addition to HIV testing discussions in the primary care setting, emergency departments and obstetrician-gynecologists should also offer routine HIV testing.[4] 

For individuals at high risk, the benefits of protection from daily PrEP should be discussed with patients. The recommended daily PrEP regimen is a single once-daily tablet containing emtricitabine and tenofovir. Patients should receive comprehensive education from primary care providers, nurses, and pharmacists before initiating and while using PrEP. These guidelines include using PrEP consistently for 1 week before sexual activity to allow for adequate drug levels to build in rectal, penile, and vaginal tissue. Patients should also receive reminders to continue PrEP for 1 week after the last sexual encounter if they want to discontinue this medication.[4] Nurses should review these educational points before discharge to reinforce understanding and ensure that patients are well-informed about proper PrEP use.

Before prescribing PrEP, all patients should undergo HIV testing using an antigen-antibody assay to confirm HIV-negative status.[4] Other recommendations before prescribing PrEP include measuring serum creatinine, GFR, and hepatitis B surface antigen. Patients should have a follow-up visit 1 month after starting PrEP to evaluate adherence and adverse effects, and then every 3 months for repeat HIV testing. If a patient acquires HIV while on PrEP, ART should be initiated promptly.[4][28] Annual HCV testing is also recommended for individuals on long-term PrEP therapy.

Creatinine measurements should be performed every 6 months or more frequently for patients taking medications for hypertension or diabetes, those aged 50 or older, and those with a GFR of less than 90 mL/min.[4] Each follow-up visit should also include counseling on safe sex practices, such as condom use and adherence to daily medication. Any patient with HBV infection who is on PrEP containing emtricitabine should be closely monitored upon discontinuation of the medication, as HBV reactivation may lead to liver injury.[27] 

Every patient should receive at least one HIV test in their lifetime, with certain populations requiring more frequent testing. Men who have sex with men, transgender women, and individuals who use IV drugs should undergo HIV testing at least annually and, in some cases, as often as every 3 months. Patients who present with sexually transmitted infections and HCV infection should be screened for HIV more frequently.[4] When performing HIV testing, the healthcare team should explain the testing methodology, the expected time for results, and the requirement to report positive results to the state health department.[29] HIV testing recommendations include a combination antibody-antigen assay or a combination antibody assay with nucleic acid testing. Further testing of the HIV viral load is recommended before prescribing ART.[4]

Patients who test positive for HIV should be referred to an infectious disease specialist or an HIV specialist. Before prescribing ART, additional testing of HIV viral load and genotype should be conducted, as genotype testing identifies potential drug resistance for the patient’s specific HIV strain.[4] Comorbidities of these patients should be carefully documented in the electronic health record, especially if the patient has concurrent HBV. Liver enzymes and HBV DNA viral load may increase if emtricitabine is discontinued abruptly.[3] Therefore, primary care and infectious disease providers should monitor patients for signs of liver damage for several weeks after discontinuing emtricitabine.[3] Mental health should also be addressed for newly diagnosed patients and those living with HIV, with referrals to psychiatry or counseling provided as needed.

The healthcare team should maintain accurate records of patients’ medication refills and appointment attendance.[4] Administrative staff, including front desk personnel, can assist by reminding patients of appointments and follow-ups. Each visit provides an opportunity to discuss adherence to ART, evaluate patient understanding of medications, and reiterate the importance of safe sex practices and disclosing their HIV status. Screening the social factors of this patient population is vital to ensure that these patients can afford their medications, understand how to take them, have support from family and friends, and have access to proper transportation to and from the physician’s office. In some cases, involving a social worker may be necessary to address these social determinants of health and ensure optimal care for patients living with HIV.

Finally, healthcare providers are responsible for educating patients about the short-term use of medications such as emtricitabine, in combination with other antiretroviral agents, as PEP.[10] Patients should also be educated about the risks of HIV exposure and informed about when and how to seek prompt medical attention. Standardized protocols should be established in clinics and hospitals to manage potential HIV exposure effectively. These protocols should include determining the HIV status of the individual requesting PEP therapy and, if possible, the HIV status of the subject with whom the patient was in contact.[10] Clinicians should also assess the timing and frequency of HIV exposure, the level of risk, and the possibility of other sexually transmitted infections.[10] Patient education should further emphasize safe sex practices, methods to minimize occupational exposure, and the importance of follow-up to monitor adherence and treatment-related adverse effects.[10]

Patients seeking PEP should be evaluated by a healthcare professional who can stratify risk factors and determine the need for ART. PEP therapy should be readily available to all healthcare workers, along with laboratory testing for those experiencing occupational exposure. Testing for occupational exposure should be promoted and simplified, so healthcare professionals can feel comfortable coming forward to protect their health. An interprofessional team approach and effective communication among physicians, advanced practice providers, pharmacists, and nurses are crucial to minimizing potential adverse effects and enhancing patient outcomes related to emtricitabine therapy.

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References

1.

Sherman KE. Management of the Hepatitis B Virus/HIV-Coinfected Patient. Top Antivir Med. 2015 Aug-Sep;23(3):111-4. [PMC free article: PMC6148934] [PubMed: 26518394]

2.

Gish RG, Trinh H, Leung N, Chan FK, Fried MW, Wright TL, Wang C, Anderson J, Mondou E, Snow A, Sorbel J, Rousseau F, Corey L. Safety and antiviral activity of emtricitabine (FTC) for the treatment of chronic hepatitis B infection: a two-year study. J Hepatol. 2005 Jul;43(1):60-6. [PubMed: 15922478]

3.

Saag MS. Emtricitabine, a new antiretroviral agent with activity against HIV and hepatitis B virus. Clin Infect Dis. 2006 Jan 01;42(1):126-31. [PubMed: 16323102]

4.

Saag MS, Benson CA, Gandhi RT, Hoy JF, Landovitz RJ, Mugavero MJ, Sax PE, Smith DM, Thompson MA, Buchbinder SP, Del Rio C, Eron JJ, Fätkenheuer G, Günthard HF, Molina JM, Jacobsen DM, Volberding PA. Antiretroviral Drugs for Treatment and Prevention of HIV Infection in Adults: 2018 Recommendations of the International Antiviral Society-USA Panel. JAMA. 2018 Jul 24;320(4):379-396. [PMC free article: PMC6415748] [PubMed: 30043070]

5.

Krakower DS, Mayer KH. Pre-exposure prophylaxis to prevent HIV infection: current status, future opportunities and challenges. Drugs. 2015 Feb;75(3):243-51. [PMC free article: PMC4354703] [PubMed: 25673022]

6.

Buchbinder SP. Maximizing the Benefits of HIV Preexposure Prophylaxis. Top Antivir Med. 2018 Apr;25(4):138-142. [PMC free article: PMC5935218] [PubMed: 29689539]

7.

Wu L, Niu X, Brunelli MK, Mugwanya KK. Adherence and HIV Protection Thresholds for Emtricitabine and Tenofovir Disoproxil Fumarate Preexposure Prophylaxis among Cisgender Women: A Systematic Review. Curr HIV/AIDS Rep. 2024 Oct;21(5):264-281. [PubMed: 39120667]

8.

Dolling DI, Desai M, McOwan A, Gilson R, Clarke A, Fisher M, Schembri G, Sullivan AK, Mackie N, Reeves I, Portman M, Saunders J, Fox J, Bayley J, Brady M, Bowman C, Lacey CJ, Taylor S, White D, Antonucci S, Gafos M, McCormack S, Gill ON, Dunn DT, Nardone A., PROUD Study Group. An analysis of baseline data from the PROUD study: an open-label randomised trial of pre-exposure prophylaxis. Trials. 2016 Mar 24;17:163. [PMC free article: PMC4806447] [PubMed: 27013513]

9.

Marfatia YS, Jose SK, Baxi RR, Shah RJ. Pre- and post-sexual exposure prophylaxis of HIV: An update. Indian J Sex Transm Dis AIDS. 2017 Jan-Jun;38(1):1-9. [PMC free article: PMC5389206] [PubMed: 28442797]

10.

Sultan B, Benn P, Waters L. Current perspectives in HIV post-exposure prophylaxis. HIV AIDS (Auckl). 2014;6:147-58. [PMC free article: PMC4216036] [PubMed: 25368534]

11.

Tanner MR, O'Shea JG, Byrd KM, Johnston M, Dumitru GG, Le JN, Lale A, Byrd KK, Cholli P, Kamitani E, Zhu W, Hoover KW, Kourtis AP. Antiretroviral Postexposure Prophylaxis After Sexual, Injection Drug Use, or Other Nonoccupational Exposure to HIV - CDC Recommendations, United States, 2025. MMWR Recomm Rep. 2025 May 08;74(1):1-56. [PMC free article: PMC12064164] [PubMed: 40331832]

12.

Chivite I, Berrocal L, de Lazzari E, Navadeh S, Lluis-Ganella C, Inciarte A, de la Mora L, González-Cordón A, Martínez-Rebollar M, Laguno M, Torres B, Blanco JL, Martínez E, Mallolas J, Ambrosioni J. Effectiveness, safety and discontinuation rates of bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) in people with HIV using real-world data: a systematic review and meta-analysis. J Antimicrob Chemother. 2024 Aug 01;79(8):1775-1783. [PubMed: 38758191]

13.

Arts EJ, Hazuda DJ. HIV-1 antiretroviral drug therapy. Cold Spring Harb Perspect Med. 2012 Apr;2(4):a007161. [PMC free article: PMC3312400] [PubMed: 22474613]

14.

Gregson J, Rhee SY, Datir R, Pillay D, Perno CF, Derache A, Shafer RS, Gupta RK. Human Immunodeficiency Virus-1 Viral Load Is Elevated in Individuals With Reverse-Transcriptase Mutation M184V/I During Virological Failure of First-Line Antiretroviral Therapy and Is Associated With Compensatory Mutation L74I. J Infect Dis. 2020 Sep 01;222(7):1108-1116. [PMC free article: PMC7459140] [PubMed: 31774913]

15.

Emtricitabine: new preparation. An antiretroviral very similar to lamivudine. Prescrire Int. 2005 Apr;14(76):54-6. [PubMed: 15875341]

16.

Ghosn J, Chow J, Gandhi M, Górgolas M, Al-Hayani A, Tookes H, Lee M, Kaiser EF, Malebranche D, Bognar FA, Gandhi-Patel B, Dai L. Rapid start with bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) as initial treatment in people with human immunodeficiency virus-1 (HIV-1): A systematic literature review of clinical and patient-reported outcomes. HIV Med. 2025 Sep;26(9):1375-1394. [PMC free article: PMC12400494] [PubMed: 40566994]

17.

Chesney M. Adherence to HAART regimens. AIDS Patient Care STDS. 2003 Apr;17(4):169-77. [PubMed: 12737640]

18.

Coutinho B, Prasad R. Emtricitabine/tenofovir (Truvada) for HIV prophylaxis. Am Fam Physician. 2013 Oct 15;88(8):535-40. [PubMed: 24364575]

19.

Drugs and Lactation Database (LactMed®) [Internet]. National Institute of Child Health and Human Development; Bethesda (MD): Jul 15, 2025. Emtricitabine. [PubMed: 30000608]

20.

Toledo T, Oliveira VG, Cattani VB, Seba K, Veloso VG, Grinsztejn B, Cardoso SW, Torres TS, Estrela R. Pharmacokinetics of Antiretroviral Drugs in Older People Living with HIV, Part II: Drugs Licensed Before 2005. Clin Pharmacokinet. 2024 Dec;63(12):1655-1666. [PubMed: 39542985]

21.

Desai M, Field N, Grant R, McCormack S. Recent advances in pre-exposure prophylaxis for HIV. BMJ. 2017 Dec 11;359:j5011. [PMC free article: PMC6020995] [PubMed: 29229609]

22.

Drak D, Barratt H, Templeton DJ, O'Connor CC, Gracey DM. Renal function and risk factors for renal disease for patients receiving HIV pre-exposure prophylaxis at an inner metropolitan health service. PLoS One. 2019;14(1):e0210106. [PMC free article: PMC6336260] [PubMed: 30653509]

23.

Kojima N, Klausner JD. Is Emtricitabine-Tenofovir Disoproxil Fumarate Pre-exposure Prophylaxis for the Prevention of Human Immunodeficiency Virus Infection Safer Than Aspirin? Open Forum Infect Dis. 2016 Jan;3(1):ofv221. [PMC free article: PMC4757763] [PubMed: 26949714]

24.

Petruccelli KCS, Baía-da-Silva DC, Val F, Valões MS, Cubas-Vega N, Silva-Neto AV, Sampaio V, Alencar A, Pecoits-Filho R, Moreira RC, Cardoso SW, Moreira RI, Leite IC, Madruga JV, Kallas EG, Alencastro PR, Hoagland B, Grinsztejn B, Santos VGV, Lacerda MVG. Kidney function and daily emtricitabine/tenofovir disoproxil fumarate pre-exposure prophylaxis against HIV: results from the real-life multicentric demonstrative project PrEP Brazil. AIDS Res Ther. 2022 Feb 24;19(1):12. [PMC free article: PMC8867642] [PubMed: 35209929]

25.

LiverTox: Clinical and Research Information on Drug-Induced Liver Injury [Internet]. National Institute of Diabetes and Digestive and Kidney Diseases; Bethesda (MD): Feb 10, 2018. Emtricitabine. [PMC free article: PMC547852] [PubMed: 31643585]

26.

Chaparala S, Da Silva RC, Papadopoulos JP. Severe Lactic Acidosis Due to Acute Intoxication by Emtricitabine/Tenofovir Alafenamide. Cureus. 2021 Oct;13(10):e19008. [PMC free article: PMC8610206] [PubMed: 34824925]

27.

Krakower DS, Cohen SE, Mayer KH. Top Questions in ID: Pre-exposure Prophylaxis for HIV. Open Forum Infect Dis. 2017 Fall;4(4):ofx185. [PMC free article: PMC5632308] [PubMed: 29026872]

28.

Zeballos D, Guimarães NS, Pereira M, Magno L, Dourado I. Performance of Adherence Measures for Oral, Tenofovir-Based HIV Pre-Exposure Prophylaxis: A Systematic Review. AIDS Behav. 2025 Sep;29(9):2841-2854. [PubMed: 40327271]

29.

Rizza SA, MacGowan RJ, Purcell DW, Branson BM, Temesgen Z. HIV screening in the health care setting: status, barriers, and potential solutions. Mayo Clin Proc. 2012 Sep;87(9):915-24. [PMC free article: PMC3538498] [PubMed: 22958996]

Disclosure: Preeti Patel declares no relevant financial relationships with ineligible companies.

Disclosure: Yasir Al Khalili declares no relevant financial relationships with ineligible companies.