Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
ATMEKSI vs FINASTERIDE
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
ATMEKSI (atazanavir/cobicistat) is a fixed-dose combination of atazanavir, an HIV-1 protease inhibitor that inhibits viral protease, preventing cleavage of viral polyproteins and resulting in immature non-infectious virions, and cobicistat, a pharmacokinetic enhancer that inhibits CYP3A, increasing atazanavir exposure.
Finasteride is a competitive 5-alpha-reductase inhibitor that prevents conversion of testosterone to dihydrotestosterone (DHT), thereby reducing DHT levels in serum and prostate tissue.
Treatment of HIV-1 infection in adults and pediatric patients weighing at least 35 kg,Off-label use as part of antiretroviral therapy in treatment-experienced patients with viral suppression
Benign prostatic hyperplasia (BPH),Male pattern baldness (androgenetic alopecia)
1.5 mg/kg IV every 4 weeks
1 mg orally once daily for androgenetic alopecia; 5 mg orally once daily for benign prostatic hyperplasia.
Terminal elimination half-life is 12 hours; renally impaired patients have prolonged half-life up to 24 hours.
Terminal elimination half-life is approximately 6-8 hours (range 4-12 hours) in young adults; prolonged to ~8 hours in elderly due to reduced clearance; clinical effect on DHT suppression persists for 24 hours post-dose.
Atazanavir is metabolized by CYP3A4; cobicistat is metabolized by CYP3A and to a minor extent by CYP2D6.
Metabolized primarily via CYP3A4 in the liver; two inactive metabolites (t-butyl side chain oxidation and glucuronide conjugate).
Primarily renal (80% unchanged) and biliary/fecal (15% as metabolites).
Renal (39% as metabolites, <0.1% as unchanged drug); fecal (57% as metabolites); biliary elimination contributes to fecal route.
95% bound to albumin and alpha-1-acid glycoprotein.
Approximately 93% bound to plasma proteins (primarily albumin and to a lesser extent alpha-1-acid glycoprotein).
2.0 L/kg, indicating extensive tissue distribution.
Volume of distribution = 76 L (approximately 1.0-1.1 L/kg), indicating extensive tissue distribution; crosses blood-brain barrier and partitions into seminal fluid.
Oral: 60-70% due to first-pass metabolism.
Oral bioavailability is approximately 63% (range 50-80%) due to incomplete absorption and first-pass metabolism; food does not significantly affect bioavailability.
GFR 15-29 m L/min: 1.0 mg/kg IV every 4 weeks; GFR <15 m L/min: not recommended
No dose adjustment required for any level of renal impairment including end-stage renal disease.
Child-Pugh A: no adjustment; Child-Pugh B: 1.0 mg/kg IV every 4 weeks; Child-Pugh C: not recommended
No formal studies in hepatic impairment. Caution advised; use not recommended in severe hepatic impairment due to potential accumulation. No specific Child-Pugh based dose recommendations.
Age 2-17 years: 1.5 mg/kg IV every 4 weeks; maximum 120 mg per dose
Not indicated in pediatric patients. Safety and efficacy not established. Avoid use in children.
No specific adjustment; monitor renal function and reduce dose if GFR <30 m L/min
No age-related dose adjustment necessary. Monitor for adverse effects (e.g., sexual dysfunction, mood changes) due to potential increased sensitivity.
None
No FDA black box warning.
Hepatotoxicity, especially in patients with pre-existing liver disease or elevated transaminases,Nephrolithiasis and cholelithiasis,Cardiac conduction abnormalities (PR interval prolongation),Risk of developing resistance if not used with other antiretrovirals,Renal impairment (cobicistat decreases estimated creatinine clearance)
Risk of high-grade prostate cancer (decreased PSA levels may mask detection),Sexual adverse effects (e.g., decreased libido, erectile dysfunction, ejaculatory disorder) may persist after discontinuation,Increased risk of mood disturbances including depression and suicidal ideation,Not indicated for use in women or children; avoid handling crushed tablets during pregnancy due to risk to male fetus
Concomitant use with drugs highly dependent on CYP3A for clearance (e.g., alfuzosin, rifampin, ergot derivatives, St. John's wort, lovastatin, simvastatin, sildenafil for pulmonary arterial hypertension),Severe hepatic impairment (Child-Pugh Class B or C)
Pregnancy (category X; risk of hypospadias in male fetuses),Known hypersensitivity to finasteride or any component of the formulation
Avoid alcohol (may exacerbate CNS effects). Grapefruit juice may increase atomoxetine exposure; limit consumption. High-fat meals do not significantly affect absorption.
No significant food interactions reported; finasteride may be taken with or without food. Avoid excessive alcohol consumption as it may worsen BPH symptoms or liver function.
First trimester: Limited human data; animal studies show no teratogenicity at therapeutic doses. Second and third trimesters: No known fetal risks. Avoid use during organogenesis unless benefit outweighs risk.
Contraindicated in pregnancy. Finasteride inhibits conversion of testosterone to dihydrotestosterone, which is critical for male fetal external genitalia development. Risk of hypospadias and other urogenital malformations if exposed in utero, particularly during first trimester. Pregnancy category X.
Not recommended during breastfeeding. M/P ratio unknown. Excreted in animal milk; potential for serious adverse reactions in nursing infants.
Not recommended. Finasteride is excreted in human milk; M/P ratio not reported. Risk to nursing infant unknown, but potential for adverse effects on male infant genitalia. Use contraindicated during breastfeeding.
No dose adjustment required in pregnancy. Pharmacokinetic profile unchanged.
No dose adjustments applicable as finasteride is contraindicated in pregnancy. No pharmacokinetic studies in pregnant women due to ethical concerns.
ATMEKSI (atomoxetine) is a selective norepinephrine reuptake inhibitor (NRI) indicated for ADHD. It has a slower onset of action (2-4 weeks) compared to stimulants. Monitor for hepatotoxicity and suicidal ideation, especially in children and adolescents. Use cautiously with hepatic impairment (reduce dose) and CYP2D6 poor metabolizers (need lower dose). Avoid concurrent MAOIs. May cause orthostatic hypotension and urinary retention.
Finasteride inhibits 5α-reductase type II, reducing conversion of testosterone to DHT. Onset of effect in benign prostatic hyperplasia (BPH) requires 6-12 months; for androgenetic alopecia, 3-6 months. Serum PSA levels decrease by approximately 50% after 6 months; multiply PSA by 2 when interpreting. Avoid handling crushed or broken tablets if pregnant or planning to become pregnant due to risk of fetal genital abnormalities. Use with caution in hepatic impairment; contraindicated in women of childbearing potential, children, and patients with hypersensitivity to 5α-reductase inhibitors.
Take ATMEKSI exactly as prescribed; do not change dose without consulting your doctor.,It may take 2-4 weeks to notice improvement in symptoms.,Avoid alcohol and grapefruit juice as they may affect drug levels.,Report any signs of liver problems (yellowing of skin/eyes, dark urine, abdominal pain) or suicidal thoughts immediately.,May cause dizziness or fainting, especially when standing up; rise slowly.,Do not stop abruptly without medical advice.
Take finasteride exactly as prescribed, once daily with or without food.,It may take 3-6 months for hair regrowth or improvement in urinary symptoms; continue therapy as directed even if no immediate benefit is noted.,Report any breast tenderness, enlargement, or lumps; also report any new onset of sexual dysfunction (e.g., decreased libido, erectile dysfunction, ejaculation disorder).,Do not donate blood while taking finasteride and for at least 1 month after stopping, to prevent exposure to a pregnant female.,Women who are pregnant or may become pregnant should not handle crushed or broken tablets due to risk of harm to male fetus.,Serum PSA levels will decrease; inform your healthcare provider that you take finasteride before any PSA test.,Store at room temperature (20-25°C) in a dry place, away from light and moisture.
No interactions on record
"Finasteride, a 5α-reductase inhibitor used for benign prostatic hyperplasia, may inhibit cytochrome P450 3A4 (CYP3A4) isoenzymes. Cyclosporine is primarily metabolized by CYP3A4. Coadministration can lead to reduced cyclosporine clearance, elevated blood concentrations, and increased risk of nephrotoxicity, hypertension, and neurotoxicity."
"Finasteride, a 5α-reductase inhibitor used for benign prostatic hyperplasia, may weakly inhibit CYP3A4, the primary enzyme responsible for sildenafil metabolism. This can lead to a modest reduction in sildenafil clearance, increasing systemic exposure and potentially enhancing both therapeutic effects and adverse events such as headache, flushing, dyspepsia, and hypotension. Clinically, this interaction is generally mild but may require dose adjustment in patients predisposed to sildenafil side effects."
"Finasteride, a 5α-reductase inhibitor, may inhibit CYP3A4-mediated metabolism of netupitant, a neurokinin-1 receptor antagonist primarily metabolized by CYP3A4. This can lead to increased netupitant plasma concentrations, potentially enhancing its adverse effects such as headache, fatigue, or dizziness. Clinically, the combination may require dose adjustment or close monitoring for netupitant toxicity."
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about ATMEKSI vs FINASTERIDE, answered by our medical review team.
ATMEKSI is a PDE5 Inhibitor that works by ATMEKSI (atazanavir/cobicistat) is a fixed-dose combination of atazanavir, an HIV-1 protease inhibitor that inhibits viral protease, preventing cleavage of viral polyproteins and resulting in immature non-infectious virions, and cobicistat, a pharmacokinetic enhancer that inhibits CYP3A, increasing atazanavir exposure.. FINASTERIDE is a 5-alpha Reductase Inhibitor that works by Finasteride is a competitive 5-alpha-reductase inhibitor that prevents conversion of testosterone to dihydrotestosterone (DHT), thereby reducing DHT levels in serum and prostate tissue.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between ATMEKSI and FINASTERIDE depend on the specific clinical indication. These are agents from distinct pharmacological classes and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of ATMEKSI is: 1.5 mg/kg IV every 4 weeks. The standard adult dose of FINASTERIDE is: 1 mg orally once daily for androgenetic alopecia; 5 mg orally once daily for benign prostatic hyperplasia.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between ATMEKSI and FINASTERIDE in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. ATMEKSI is classified as Category C. First trimester: Limited human data; animal studies show no teratogenicity at therapeutic doses. Second and third trimesters: No known fetal risks. Avoid use during organogenesis u. FINASTERIDE is classified as Category D/X. Contraindicated in pregnancy. Finasteride inhibits conversion of testosterone to dihydrotestosterone, which is critical for male fetal external genitalia development. Risk of hypos. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.