Wednesday, July 19, 2023

darunavir (da-ru-na-veer) Prezista

 Indications

HIV infection (must be used with ritonavir and with

other antiretrovirals).

Action

Inhibits HIV-1 protease, selectively inhibiting the cleavage

of HIV-encoded specific polyproteins in infected

cells. This prevents the formation of mature virus particles.

Therapeutic Effects: Increased CD4 cell

counts and decreased viral load with subsequent

slowed progression of HIV infection and its sequelae.

Pharmacokinetics

Absorption: Without ritonavir—37% absorbed

following oral administration; with ritonavir—82%.

Foodqabsorption by 30%.

Distribution: Unknown.

Protein Binding: 95% bound to plasma proteins.

Metabolism and Excretion: Extensively metabolized

by CYP3A enzyme system. 41% eliminated unchanged

in feces, 8% in urine.

Half-life: 15 hr.

TIME/ACTION PROFILE

ROUTE ONSET PEAK DURATION

PO unknown 2.5–4 hr 12 hr

Contraindications/Precautions

Contraindicated in: Concurrent alfuzosin, dronedarone,

colchicine (in renal/hepatic impairment), ranolazine,

sildenafil (Revatio), ergot derivatives, lurasidone,

midazolam (PO), pimozide, triazolam, lovastatin,

simvastatin, rifampin, or St. John’s wort; Lactation:

Avoid breast feeding (HIV may be transmitted in human

milk).

Use Cautiously in: Hepatic impairment; Sulfa allergy;

Geri: Consider age-related impairment in hepatic

function, concurrent chronic disease states and drug

therapy; OB: May be used during pregnancy (if benefits

of use generally outweigh fetal risk); Pedi: Children 3

yr (safety and efficacy not established).

Adverse Reactions/Side Effects

Based on concurrent use with ritonavir.

GI: HEPATOTOXICITY, constipation, diarrhea, nausea,

vomiting. Endo: hyperglycemia.Metab: body fat redistribution.

Derm: DRUG RASH WITH EOSINOPHILIA AND

SYSTEMIC SYMPTOMS (DRESS), STEVENS-JOHNSON SYNDROME,

TOXIC EPIDERMAL NECROLYSIS, rash, acute generalized

exanthematous pustulosis. Misc: immune reconstitution

syndrome.

Interactions

Drug-Drug: Darunavir and ritonavir are both inhibitors

of CYP3A, CYP2D6, and P-gp and are metabolized

by CYP3A. Multiple drug-drug interactions can be expected

with drugs that share, inhibit, or induce these

pathways. Consult product information for more specific

details.qblood levels and risk of toxicity from ergot

derivatives (dihydroergotamine, ergotamine,

methylergonovine), sildenafil (Revatio), alfuzosin,

dronedarone, ranolazine, lurasidone, pimozide,

lovastatin, simvastatin, midazolam (oral),

and triazolam; concurrent use is contraindicated. May

qcolchicine levels and cause serious/life-threatening

reactions;pdose of colchicine; concurrent use contraindicated

in patients with renal or hepatic impairment.

Rifampinqmetabolism and maypantiretroviral effectiveness,

concurrent use is contraindicated. Concurrent

use with indinavir mayqdarunavir and indinavir levels.

qlevels and risk of myopathy from atorvastatin,

rosuvastatin, or pravastatin; use lowest dose of

these agents; do not exceed atorvastatin dose of 20 mg/

day. Concurrent use with efavirenz results inpdarunavir

levels andqefavirenz levels; use combination

cautiously. Lopinavir/ritonavir mayplevels; concurrent

use not recommended. Saquinavir mayplevels;

concurrent use not recommended. Mayqmaraviroc

levels;pmaraviroc dose to 150 mg twice daily. Mayq

levels of lidocaine, quinidine, disopyramide, mexiletine,

propafenone, flecainide, and amiodarone;

use cautiously and with available blood level monitoring.

qdigoxin levels; blood level monitoring recommended.

Mayqcarbamazepine levels; blood level

monitoring recommended. Maypphenytoin or phenobarbital

levels; blood level monitoring recommended.

Mayplevels of warfarin; monitor INR. May

qlevels of trazodone, amitriptyline, desipramine,

imipramine, and nortriptyline; use cautiously and

pdose if necessary. Mayqlevels of clarithromycin;p

dose of clarithromycin if CCr 60 mL/min. Mayqlevels

of ketoconazole and itraconazole; do not exceed

itraconazole or ketoconazole dose 200 m g/day. Ketoconazole

and itraconazole mayqlevels. Mayp

levels of voriconazole; concurrent use not recommended.

Concurrent use with rifabutinqrifabutin levels

andqdarunavir levels; (may be due to ritonavir);p

rifabutin dose to 150 mg every other day. Rifapentin

mayplevels; concurrent use not recommended. Mayq

levels of beta-blockers; may need topdose. Mayq

levels of amlodipine, diltiazem, felodipine, nifedipine,

nicardipine, or verapamil; monitor clinical response

carefully. Dexamethasone mayplevels and effectiveness.

Mayqlevels and the risk of Cushing’s

syndrome and adrenal suppression with systemic budesonide

and prednisone; consider alternative therapy.

Mayqlevels of inhaled/nasal fluticasone and budesonide;

choose alternative inhaled/nasal

corticosteroid. Mayqlevels of cyclosporine, tacrolimus,

or sirolimus; blood level monitoring recommended.

Mayqlevels of everolimus; concurrent use not recommended. Mayplevels of methadone. Mayq

risperidone and thioridazine levels; may need top

dose. Mayqlevels of sildenafil, vardenafil, tadalafil,

or avanafil; single dose should not exceed the following(

sildenafil 25 mg in 48 hr; vardenafil 2.5 mg in 72

hr; tadalafil 10 mg in 72 hr); concurrent use with avanafil

not recommended. Mayplevels of sertraline and

paroxetine; adjust dose by clinical response. Mayp

levels and contraceptive efficacy of some combined

hormonal contraceptives and progestin-only contraceptives

(alternative methods of nonhormonal contraception

recommended). Mayqlevels of salmeterol;

concurrent use not recommended. Mayq

bosentan levels; initiate bosentan at 62.5 mg once

daily or every other day once patient receiving darunavir

for 10 days; if patient already receiving bosentan,

discontinue bosentan 36 hr before initiation of darunavir

and then restart bosentan 10 days later at 62.5

mg once daily or every other day. Mayqtadalafil (Adcirca)

levels; initiate tadalafil (Adcirca) at 20 mg once

daily once patient receiving darunavir for 1 wk; if patient

already receiving tadalfil (Adcirca), discontinue

tadalafil (Adcirca) 24 hr before initiation of darunavir

and then restart tadalafil (Adcirca) 7 days later at 20

mg once daily. Concurrent use with simeprevir results

inqdarunavir levels andqsimeprevir levels; concurrent

use not recommended. Mayqlumefantrine levels

and risk of QT interval prolongation. Mayqquetiapine

levels;pquetiapine dose to 1⁄6 of current dose.

Mayqlevels of and risk of bleeding with apixaban,

dabigatran, and rivaroxaban; concurrent use not

recommended. Mayqdasatinib and nilotinib levels;

may need topdose orqdosing interval of dasatinib

and nilotinib. Mayqvinblastine and vincristine levels;

may need to temporarily hold darunavir-ritonavir

or initiate another antiretroviral regimen. Mayqlevels

of buspirone, diazepam, estazolam, midazolam

(IV), and zolpidem;pdose of sedative. Maypomeprazole

levels; considerqomeprazole dose (not to

exceed 40 mg/day).

Drug-Natural Products: St. John’s wortqmetabolism

and maypantiretroviral effectiveness; concurrent

use contraindicated.

Route/Dosage

Genotypic testing of the baseline virus is recommended

prior to initiating treatment in therapy-experienced patients.

This testing is performed to screen for darunavir

resistance associated substitutions, which may be helpful

in determining whether the HIV virus will be susceptible

to darunavir.

PO (Adults): Therapy-naive—800 mg once daily

with ritonavir 100 mg once daily; Therapy-experienced

(with no darunavir resistance associated substitution)—

800 mg once daily with ritonavir 100 mg

once daily; Therapy-experienced (with 1 darunavir

resistance associated substitution or if genotypic

testing not performed)—600 mg twice daily with ritonavir

100 mg twice daily; Pregnancy—600 mg twice

daily with ritonavir 100 mg twice daily; if patient taking

800 mg once daily with ritonavir 100 mg once daily before

pregnancy, may continue with this regimen if they

are virologically supressed (HIV-1 RNA 50 copies/

mL), and if switch to twice daily regimen may compromise

tolerability or compliance.

PO (Oral suspension or tablets) (Children 3–17

yr and 40 kg): Therapy-naive—800 mg once daily

with ritonavir 100 mg once daily; Therapy-experienced

(with no darunavir resistance associated substitution)—

800 mg once daily with ritonavir 100 mg

once daily; Therapy-experienced (with 1 darunavir

resistance associated substitution or if genotypic

testing not performed)—600 mg twice daily with ritonavir

100 mg twice daily.

PO (Oral suspension or tablets) (Children 3–17

yr and 30–39.9 kg): Therapy-naive—675 mg once

daily with ritonavir 100 mg once daily; Therapy-experienced

(with no darunavir resistance associated

substitution)—675 mg once daily with ritonavir 100

mg once daily; Therapy-experienced (with 1 darunavir

resistance associated substitution or if genotypic

testing not performed)—450 mg twice daily

with ritonavir 60 mg twice daily.

PO (Oral suspension or tablets) (Children 3–17

yr and 15–29.9 kg): Therapy-naive—600 mg once

daily with ritonavir 100 mg once daily; Therapy-experienced

(with no darunavir resistance associated

substitution)—600 mg once daily with ritonavir 100

mg once daily; Therapy-experienced (with 1 darunavir

resistance associated substitution or if genotypic

testing not performed)—375 mg twice daily

with ritonavir 48 mg twice daily.

PO (Oral suspension only) (Children 3–17 yr

and 14–14.9 kg): Therapy-naive—490 mg once

daily with ritonavir 96 mg once daily; Therapy-experienced

(with no darunavir resistance associated substitution)—

490 mg once daily with ritonavir 96 mg

once daily; Therapy-experienced (with 1 darunavir

resistance associated substitution or if genotypic

testing not performed)—280 mg twice daily with ritonavir

48 mg twice daily.

PO (Oral suspension only) (Children 3–17 yr

and 13–13.9 kg): Therapy-naive—455 mg once

daily with ritonavir 80 mg once daily; Therapy-experienced

(with no darunavir resistance associated substitution)—

455 mg once daily with ritonavir 80 mg

once daily; Therapy-experienced (with 1 darunavir

resistance associated substitution or if genotypic

testing not performed)—260 mg twice daily with ritonavir

40 mg twice daily.

PO (Oral suspension only) (Children 3–17 yr

and 12–12.9 kg): Therapy-naive—420 mg once daily with ritonavir 80 mg once daily; Therapy-experienced

(with no darunavir resistance associated substitution)—

420 mg once daily with ritonavir 80 mg

once daily; Therapy-experienced (with 1 darunavir

resistance associated substitution or if genotypic

testing not performed)—240 mg twice daily with ritonavir

40 mg twice daily.

PO (Oral suspension only) (Children 3–17 yr

and 11–11.9 kg): Therapy-naive—385 mg once

daily with ritonavir 64 mg once daily; Therapy-experienced

(with no darunavir resistance associated substitution)—

385 mg once daily with ritonavir 64 mg

once daily; Therapy-experienced (with 1 darunavir

resistance associated substitution or if genotypic

testing not performed)—220 mg twice daily with ritonavir

32 mg twice daily.

PO (Oral suspension only) (Children 3–17 yr

and 10–10.9 kg): Therapy-naive—350 mg once

daily with ritonavir 64 mg once daily; Therapy-experienced

(with no darunavir resistance associated substitution)—

350 mg once daily with ritonavir 64 mg

once daily; Therapy-experienced (with 1 darunavir

resistance associated substitution or if genotypic

testing not performed)—200 mg twice daily with ritonavir

32 mg twice daily.

Availability

Tablets: 75 mg, 150 mg, 600 mg, 800 mg. Oral suspension:

100 mg/mL. In combination with: cobicistat

(Prezcobix). See Appendix B.


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