maraviroc

(ma-ra-vi-rok) maraviroc,

Celsentri

(trade name),

Selzentry

(trade name)

Classification

Therapeutic: antiretrovirals
Pharmacologic: ccr5 co receptor antagonists
Pregnancy Category: B

Indications

HIV infection (with other antiretrovirals), specifically in treatment-experienced or treatment-naive patients with CCR5–tropic HIV-1 infection.genetic implication Use should be determined by tropism testing.

Action

genetic implication Blocks a specific receptor on CD-4 and T-cell surfaces which prevents CCR5–tropic HIV-1 from entering.

Therapeutic effects

Decreased invasion of CD-4 and T-cells by CCR5–tropic HIV-1 virus resulting in viral replication.

Pharmacokinetics

Absorption: 2–33% absorbed following oral administration.Distribution: Unknown.Metabolism and Excretion: Mostly metabolized by the liver (CYP3A enzyme system); 8% renal excretion as unchanged drug.Half-life: 14–18 hr.

Time/action profile (blood levels)

ROUTE	ONSET	PEAK	DURATION
PO	unknown	0.5–4 hr	1–2 hr

Contraindications/Precautions

Contraindicated in: Dual/mixed or CXCR4–tropic HIV-1;Patients with severe renal impairment or end-stage renal disease who are taking potent CYP3A inhibitors or inducers; Lactation: Breast feeding not recommended for HIV-infected patients.Use Cautiously in: Pre-existing liver disease including hepatitis B or C (may ↑ risk of hepatotoxicity);Cardiovascular disease or risk factors (↑ risk of cardiovascular events);Orthostatic hypotension;Hepatic impairment;Patients with severe renal impairment or end-stage renal disease who are not taking potent CYP3A inhibitors or inducers (dose should be ↓ if symptoms of orthostatic hypotension occur); Geriatric: Consider age-related ↓ in renal/hepatic function, concurrent drug therapy and concomitant disease; Obstetric: Use only if clearly needed; Pediatric: Children <16 yr (safety not established).

Adverse Reactions/Side Effects

Central nervous system

dizziness (most frequent)

Cardiovascular

myocardial ischemia/infarction
orthostatic hypotension

Respiratory

cough (most frequent)
upper respiratory tract infection (most frequent)

Gastrointestinal

abdominal pain (most frequent)
appetite disorder
hepatotoxicity (life-threatening)

Dermatologic

drug rash with eosinophilia and systemic symptoms (life-threatening)
stevens-johnson syndrome (life-threatening)
toxic epidermal necrolysis (life-threatening)

Musculoskeletal

musculoskeletal pain

Miscellaneous

allergic reactions (life-threatening)
fever (most frequent)
immune reconstitution syndrome
↑ risk of infection

Interactions

Drug-Drug interaction

Levels are ↑ by CYP3A inhibitors including protease inhibitors (excluding tipranavir/ritonavir), delavirdine, ketoconazole, itraconazole, clarithromycin, nefazodone, telithromycin, lopinavir/ritonavir, saquinavir, and atazanavir l need to ↓ dosage of maraviroc.Levels are ↓ by CYP3A inducers including efavirenz, rifampin, etravirine, carbamazepine, phenytoin, and phenobarbital ; need to ↑ dose of maraviroc.Antihypertensives may ↑ risk of orthostatic hypotension.St. John's wort may ↓ levels; concurrent use not recommended.

Route/Dosage

Oral (Adults) Concurrent CYP3A inhibitors (with or without potent CYP3A inducers) including protease inhibitors (except tipranavir/ritonavir), delavirdine, ketoconazole, itraconazole, clarithromycin, and other potent CYP3A inhibitors—150 mg twice daily; Concurrent CYP3A inducers (without a potent CYP3A inhibitor) including efavirenz, rifampin, etravirine, carbamazepine, phenytoin, and phenobarbital—600 mg twice daily; Other concomitant medications including NRTIs, tipranavir/ritonavir, nevirapine, raltegravir, enfuvirtide, and other drugs that are not strong inhibitors/inducers of CYP3A—300 mg twice daily.

Renal Impairment

(Adults) CCr <30 mL/min or on hemodialysis (not receiving potent CYP3A inhibitors or inducers)—300 mg twice daily; ↓ dose to 150 mg twice daily if symptoms of orthostatic hypotension occur; CCr <30 mL/min or on hemodialysis (receiving potent CYP3A inhibitors or inducers)—Contraindicated.

Availability

Tablets: 150 mg, 300 mg

Nursing implications

Nursing assessment

Assess patient for change in severity of HIV symptoms and for symptoms of opportunistic infections throughout therapy.
Assess for signs or symptoms of hepatitis or allergic reaction (pruritic rash, jaundice, dark urine, vomiting, abdominal pain, fever, eosinophilia, elevated IgE). If symptoms occur, discontinue maraviroc immediately.
Assess for rash periodically during therapy. May cause Stevens-Johnson syndrome. Discontinue therapy if severe or if accompanied with fever, general malaise, fatigue, muscle or joint aches, blisters, oral lesions, conjunctivitis, hepatitis, and/or eosinophilia.
Lab Test Considerations: genetic implication Testing for CCR5–tropic HIV-1 should be obtained prior to initiating therapy.
- Monitor viral load and CD4 cell count regularly during therapy.
- May cause ↑ AST, ALT, total bilirubin, amylase, and lipase.
- May cause ↓ absolute neutrophil count.

Potential Nursing Diagnoses

Risk for infection (Indications)
Deficient knowledge, related to medication regimen (Patient/Family Teaching)

Implementation

Oral: May be administered without regard to food. Tablets should be swallowed whole; do not break, crush, or chew.

Patient/Family Teaching

Emphasize the importance of taking maraviroc as directed, at the same time each day. Advise patient to read the Patient Information that comes with the medication with each Rx refill. Maraviroc must always be used in combination with other antiretroviral drugs. Do not take more than prescribed amount and do not stop taking without consulting health care professional. Take missed doses as soon as remembered, then return to regular dose schedule. If it is within 6 hr of next dose, omit dose and take next dose at regular time. Do not double doses.
Instruct patient that maraviroc should not be shared with others.
Inform patient that maraviroc does not cure AIDS or prevent associated or opportunistic infections. Maraviroc does not reduce the risk of transmission of HIV to others through sexual contact or blood contamination. Caution patient to use a condom and to avoid sharing needles or donating blood to prevent spreading the AIDS virus to others. The long-term effects of maraviroc are unknown at this time. If new symptoms of infection develop after starting maraviroc, notify health care professional.
Immune reconstitution syndrome may trigger opportunistic infections or autoimmune disorders. Notify health care professional if symptoms occur.
Advise patient to discontinue maraviroc and notify health care professional if chest pain, signs of hepatotoxicity (itchy rash, yellow-colored skin or eyes, dark urine, vomiting, or abdominal pain) or signs of immune reconstitution syndrome (signs and symptoms of an infection) occur.
May cause dizziness. Caution patient to avoid driving and other activities requiring alertness until response to medication is known.
Advise patient to make position changes slowly to minimize postural hypotension.
Advise patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to consult with health care professional before taking other medications, especially St. John's Wort; may decrease effectiveness of maraviroc.
Advise patient to notify health care professional if pregnancy is planned or suspected or if breast feeding.
Emphasize the importance of regular follow-up exams and blood counts to determine progress and monitor for side effects.

Evaluation/Desired Outcomes

Delayed progression of AIDS and decreased opportunistic infections in patients with HIV.
Decrease in viral load and increase in CD4 cell counts.