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Pifeltro

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Medically reviewed

Marina Burgos

Last updated on 22/12/2025

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Pifeltro

What is Pifeltro? (Overview and Quick Facts)

Property Description
Active ingredient Doravirine (INN)
Form Film-coated tablet
Pharmacological class Non-Nucleoside Reverse Transcriptase Inhibitor (NNRTI)
Common use Treatment of HIV-1 infection (in combination therapy)
Origin Synthetic small molecule drug

Pifeltro: Definition and Pharmacological Class

Pifeltro is a specific prescription HIV medicine utilized as part of a regimen to treat Human Immunodeficiency Virus type 1 (HIV-1 infection). The drug is supplied as a film-coated tablet for oral administration and contains the sole active ingredient, Doravirine. Doravirine is classified as an antiretroviral agent, belonging specifically to the pharmacological class of Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs). Doravirine is a synthetic compound that has been clinically recognized for its targeted mechanism within the NNRTI class.

What is the Active Component in Pifeltro? (Doravirine's Role)

The active component in Pifeltro is Doravirine, which is the single substance responsible for the drug’s function and is used in both treatment-naïve and treatment-experienced adults. Doravirine serves as a well-tolerated and effective agent in certain patient populations. Doravirine acts by blocking the function of reverse transcriptase, an enzyme used by the virus to convert its genetic material into DNA, thereby inhibiting viral multiplication. Pifeltro is differentiated as a single-entity product containing Doravirine alone, allowing for flexible regimen customization, unlike the fixed-dose combination product, Delstrigo.

General Purpose: Role in HIV-1 Management

Pifeltro's general purpose is to serve as a foundational element within a patient’s combination antiretroviral therapy (ART) regimen, particularly when an individualized combination is required. Its action of interrupting the viral life cycle allows the drug to significantly reduce the quantity of HIV-1 virus in the bloodstream, a measure known as the viral load. By maintaining a low viral load, Pifeltro helps preserve the patient’s immune function, which is critical for the long-term management of HIV-1 infection. For instance, Pifeltro is typically used alongside other antiviral agents in adults and pediatric patients (weighing at least 35 kg) to ensure comprehensive viral suppression.

Regulatory References

  1. Pifeltro (doravirine) EPAR
  2. HIV Medicines (MedlinePlus)

What side effects are possible with Pifeltro?

Possible Side Effects and Safety Information

The safety profile of Pifeltro (doravirine) is based on adverse reactions observed in clinical trials, classified according to their frequency and the physiological system affected, as documented in regulatory sources.

Frequency-Classified Adverse Reactions

The officially listed side effects are categorized by frequency, reflecting how often they were observed in study populations:

  • Common (may affect up to 1 in 10 people): Reactions include headache, dizziness, fatigue, nausea, diarrhoea, abnormal dreams, insomnia, and rash.
  • Uncommon (may affect up to 1 in 100 people): Documented effects include hypersensitivity reactions, abdominal discomfort, vomiting, depression, anxiety, and laboratory abnormalities such as elevated liver enzymes (ALT/AST), lipase, and creatine kinase (CK).

Systemic Safety Considerations and Constraints

Adverse events are grouped by System-Organ-Class (SOC), including effects on the Nervous System (e.g., headache, dizziness), Gastrointestinal Disorders, Psychiatric Disorders (e.g., abnormal dreams, insomnia), and the Immune System.

Regulatory documents highlight the potential for serious adverse reactions, including severe hypersensitivity reactions (such as Stevens-Johnson Syndrome) and high-level concerns regarding hepatic toxicity (liver damage), which is associated with this class of antiretroviral agents.

Population-Specific Safety Notes

The official labeling notes that Pifeltro has not been studied in patients with severe hepatic impairment (Child-Pugh Class C), and its use in this population is not recommended. Caution is advised for individuals with pre-existing, clinically significant liver disease. Additionally, a critical safety restriction involves the concurrent use of Pifeltro with certain strong enzyme-inducing drugs, which may lead to a loss of therapeutic effect.

Overdose and Emergency Response

Overdose and When to Seek Help

The official regulatory documents for Pifeltro (doravirine) focus on mandated emergency procedures and management, as the labeling does not explicitly document specific acute clinical signs or symptoms resulting from an excessive single dose. Studies using high doses, exceeding 12 times the recommended daily dose, did not result in unique overdose presentations being defined in the prescribing information.

Emergency Action Required

Any suspected overdose requires immediate action. Regulatory authorities explicitly mandate that individuals must seek immediate medical attention and contact a regional Poison Control center for guidance on the proper management of the suspected drug overdose.

Treatment and Monitoring

There is no known specific treatment or antidote available for Pifeltro overdose. Due to this constraint, management relies entirely on procedural and supportive steps:

  • Standard supportive treatment must be applied as clinically required.
  • The patient must be closely monitored following a suspected overdose to manage any resulting clinical status changes.
  • The active ingredient, doravirine, exhibits high protein binding (approximately 76%). This characteristic suggests that dialysis is considered unlikely to be an effective measure for removing the drug from the system.

No population-specific overdose considerations are provided in the official regulatory sections for the elderly, pediatric, or renally/hepatically impaired patient groups.

Therapeutic Uses of Pifeltro

What Pifeltro Treats: Main Uses and Benefits

The primary role of Pifeltro (doravirine), when used as part of a combination regimen, is to provide long-term therapeutic control over a chronic viral condition: Human Immunodeficiency Virus type 1 (HIV-1) infection. This medicine is used in combination with other antiviral medicines and supports the process of reducing the risk of damage to the immune system.

The medication is considered relevant for managing two key aspects: systemic viral activity and progressive immune system compromise. It may assist with keeping the virus suppressed and supporting the body’s natural defense mechanisms.

Clinical Scenarios and Therapeutic Benefit

Pifeltro is commonly used across conditions characterized by periods of heightened symptoms related to the underlying infection. Its use is relevant for individuals starting their initial combination anti-HIV therapy and for those whose viral activity is already under control but are switching treatments to maintain that successful control.

This treatment contributes to easing the overall symptom load and helps maintain a sense of stability when symptoms are more noticeable.

Quick Fact: Relief for Systemic Viral Activity

Pifeltro supports the management of systemic viral activity, which is an important aspect of addressing the functional strain and immune issues associated with the condition.

Regulatory References

  1. European Medicines Agency overview

Eligibility and Restrictions for Use

Pifeltro is approved for use in adults and adolescents aged 12 years and older weighing at least 35 kg for the treatment of HIV-1 infection, always in combination with other antiretroviral agents. It is approved only for patients who do not have past or present evidence of resistance to its drug class (NNRTI) [1.1, 1.3].

Contraindications (Who Must Not Use)

Pifeltro is contraindicated and must not be used by patients who are concurrently taking strong CYP3A enzyme inducers, such as rifampin, carbamazepine, or St. John’s wort, due to the risk of reduced drug effectiveness [1.4, 3.2]. It is also contraindicated for patients with rare hereditary problems like total lactase deficiency or galactose intolerance, as the tablets contain lactose [1.3, 2.1].

Use in Specific Populations

Population Regulatory Status Limitation / Restriction
Pediatric Not established Safety and efficacy not established in children under 12 years or weighing less than 35 kg [1.3, 1.6].
Hepatic Impairment Conditional Use Caution is advised for severe hepatic impairment (Child-Pugh Class C), as it has not been studied in this group [1.3, 2.5].
Renal Impairment Conditional Use Not studied in patients with end-stage renal disease or on dialysis [1.3].
Pregnancy Conditional Use No adequate human data; use only if potential benefit justifies the risk [1.2, 2.3].
Lactation Not Recommended Breastfeeding is not recommended for women with HIV-1 due to the risk of postnatal transmission of the virus [1.4, 2.7].

What should I know about interactions with other medicines?

Interactions with other medicines and products

The interaction profile for Pifeltro (doravirine) is primarily governed by the Cytochrome P450 (CYP)3A enzyme metabolic pathway, as doravirine is largely cleared through this route. Co-administration with certain medicinal products or supplements can significantly alter doravirine plasma levels, impacting efficacy.

Contraindicated Combinations

Co-administration with strong CYP3A inducers is formally contraindicated. These substances cause a significant decrease in doravirine concentration, which may lead to a loss of therapeutic effect. Prohibited medicines and substances include the anticonvulsants carbamazepine, phenytoin, and phenobarbital; the antimycobacterial rifampin; and the herbal product St. John's wort.

Exposure Modification and Administration Timing

Combinations with moderate CYP3A inducers (such as rifabutin) are not prohibited but require a modification to the administration schedule. Pifeltro must be taken twice daily (100 mg approximately 12 hours apart) when used concurrently with these medicines. Conversely, co-administration with CYP3A inhibitors may increase doravirine plasma concentration, but no dose adjustment is necessary. Doravirine itself is classified as a weak CYP3A inducer, which may decrease the exposure of other sensitive CYP3A substrates. Pifeltro may be taken with or without food.

Mechanism of Action

Non-Nucleoside Reverse Transcriptase Inhibition

Pifeltro (doravirine) is a non-nucleoside reverse transcriptase inhibitor (NNRTI). It functions by targeting and binding to the reverse transcriptase (RT) enzyme of the Human Immunodeficiency Virus type 1 (HIV-1). This enzyme is essential for converting the single-stranded viral RNA genome into double-stranded viral DNA.

Allosteric Modulation and Replication Restriction

Pifeltro binds specifically to an allosteric site on the RT enzyme, non-competitively, and does not require phosphorylation. This binding induces a conformational change in the enzyme's structure, which directly inhibits its polymerase activity. The resulting modulation of the RT enzyme's function prevents the necessary initial step of viral replication within the host cell.

Downstream Physiological Consequence

By suppressing the activity of reverse transcriptase, Pifeltro restricts the propagation of viral components by preventing the formation of proviral DNA. This action interrupts the HIV-1 replication cascade, maintaining the limitation of the viral life cycle progression and restricting the spread of viral genetic material.

Dosage and Administration Information

How to Use Pifeltro: Official Administration Guidelines

Pifeltro (doravirine) is used as part of a combination antiretroviral therapy (ART) regimen, following established usage patterns. It is administered as a 100 mg film-coated tablet and is intended for long-term use in the management of HIV-1 infection. The guidelines focus on establishing a consistent administration schedule.

Administration Scope

Instruction Official Guideline
Route of administration The tablet must be taken orally and swallowed whole.
Dosing schedule The standard dose is one 100 mg tablet once daily. The dose is increased to one 100 mg tablet twice daily when co-administered with moderate CYP3A inducers, such as rifabutin.
Timing in relation to meals Pifeltro may be taken with or without food.
Age-group rules The standard 100 mg dose is used for adults and pediatric patients weighing at least 35 kg.
Missed-dose rules If a dose is missed by less than 12 hours, take it immediately. If missed by more than 12 hours, skip the dose and resume the normal schedule. Do not take two doses at one time.

Resulting Procedural Structure

Official step sequence:

  • Take one 100 mg tablet orally.
  • Swallow the tablet whole.
  • Take once daily (unless co-administered with specific interacting medications).
  • Continue taking the tablet in combination with other antiretroviral agents for the course of treatment.

The guidelines establish a clear, standardized approach for taking Pifeltro as an oral agent, defining its role as a foundational component within a combination ART plan. Dosing remains consistent across most patient groups, with the variation being the specific twice-daily frequency required when certain interacting medications are concurrently used.

Recent Clinical Evidence

Pifeltro: Recent Clinical Evidence

Pifeltro (doravirine) is a non-nucleoside reverse transcriptase inhibitor (NNRTI) developed for the treatment of HIV-1 infection in adults. Research has investigated its proposed mechanism of action, which is focused on inhibiting the function of the HIV-1 reverse transcriptase enzyme, crucial for the virus's replication cycle.

Clinical Trial Outcomes

The efficacy and safety of doravirine have been evaluated in large-scale, international Phase 3 clinical trials, including DRIVE-AHEAD and DRIVE-FORWARD, involving adults who were new to antiretroviral treatment (treatment-naïve).

Trial (Treatment-Naïve) Comparator Regimen Primary Endpoint (Week 48)
DRIVE-AHEAD Efavirenz-based regimen Demonstrated non-inferior viral suppression.
DRIVE-FORWARD Darunavir/Ritonavir-based regimen Demonstrated non-inferior viral suppression.

In both trials, the primary efficacy endpoint assessed the percentage of participants who achieved viral suppression (HIV-1 RNA less than 50 copies/mL) at 48 weeks. Doravirine-based regimens were found to achieve viral suppression rates that were comparable (non-inferior) to the active comparator regimens.

Safety and Tolerability Profiles

Adverse event data reported across these Phase 3 trials informed the agent's tolerability profile. In the DRIVE-AHEAD trial, lower rates of certain pre-specified neuropsychiatric adverse events (e.g., dizziness, sleep disturbances) were reported in the doravirine group compared to the efavirenz-based regimen. Across both trials, common adverse events included nausea, headache, dizziness, and fatigue.

Long-term follow-up studies extending to 96 weeks and beyond further reported on the durability of the observed viral suppression and the maintenance of the agent's safety profile over time.

Frequently Asked Questions (FAQ)

Common questions about Pifeltro (FAQ)

Q: What is Pifeltro (Dorovirin) used for?

A: Pifeltro is an FDA-approved prescription medicine used in combination with other antiretroviral agents to treat Human Immunodeficiency Virus type 1 (HIV-1) infection in adults who have not been previously treated with antiretroviral therapy.

Q: How does Pifeltro work?

A: Pifeltro belongs to a class of medications called non-nucleoside reverse transcriptase inhibitors (NNRTIs). The medication is designed to interfere with the HIV-1 life cycle. Further details on the mechanism of action can be discussed with a healthcare provider.

Q: What are the most common side effects of Pifeltro?

A: The most frequently reported adverse effects associated with Pifeltro may include headache, nausea, and diarrhea. This is not a complete list, and individuals should discuss all potential side effects and concerns with their healthcare professional.

Q: Can Pifeltro be taken with other medications?

A: Pifeltro has the potential for drug interactions with a variety of other medicines, including certain anticonvulsants, antituberculosis medications, and herbal supplements like St. John's Wort. It is essential to provide your healthcare provider with a complete list of all prescriptions, over-the-counter drugs, and supplements being used to evaluate potential interactions.

How should Pifeltro be stored and disposed of?

Storage and Disposal Requirements for Pifeltro

Official regulatory guidelines mandate precise conditions for the storage and handling of Pifeltro (doravirine) tablets.

Storage Conditions

Requirement Official Specification
Temperature Controlled room temperature: 68 F to 77 F (20 C to 25 C)
Protection Must be protected from moisture; keep bottle tightly closed with desiccant inside.
Container Store only in the original container.
Child Safety Keep out of the sight and reach of children.

Disposal Instructions

Unused or expired Pifeltro must be disposed of properly. The product should be taken to a formal drug take-back program or a DEA-authorized collector. If this is unavailable, the tablets must be mixed with an undesirable substance, sealed in a bag, and discarded in the household trash. The tablets must not be flushed down a sink or toilet.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

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