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Cited by 285Sexual function and dysfunction studiesPharmacogenetics and Drug MetabolismPharmaceutical studies and practices

The DOI matches its Crossref record; 26 of the 26 references it cites were found in a registry or an index; none of the 26 sources its claims cite is checked for support yet.

Tadalafil pharmacokinetics in healthy subjects

Open access

Abstract

Aims: To characterize tadalafil plasma pharmacokinetics in healthy subjects following single and multiple doses. Methods: Noncompartmental parameters were calculated for healthy subjects receiving a single 2.5–20‐mg tadalafil dose in 13 clinical pharmacology studies. An integrated statistical analysis of results in 237 subjects provided global averages and an assessment of effects of body mass index (BMI), age, gender and smoking status. Diurnal variation, food effects and proportionality of exposure to dose were analysed in three studies. Multiple‐dose pharmacokinetics were evaluated in a separate study in which parallel groups of 15 subjects received 10 or 20 mg tadalafil once daily for 10 days. Results: Tadalafil was absorbed rapidly with mean Cmax (378 µg l−1 for 20 mg) observed at 2 h; thereafter, concentrations declined nearly monoexponentially with a mean (5th, 95th percentiles) t1/2 of 17.5 (11.5, 29.6) hours. Mean oral clearance (CL/F) was 2.48 (1.35, 4.35) l h−1 and apparent volume of distribution (Vz/F) was 62.6 (39.5, 92.1) l. No clinically meaningful effect of BMI, age, gender or smoking was identified. Exposure was not substantially affected by time of dosing. Food had negligible effects on bioavailability as assessed by 90% confidence intervals for Cmax and AUC mean ratios. Parameters were proportional to dose, indicating that doubling the dose doubled exposure. Steady state was attained by day 5 following once‐daily administration, and accumulation (1.6‐fold) was consistent with the t 1/2. Conclusions: Tadalafil pharmacokinetics are linear with respect to dose and time, and are not affected by food. Systemic clearance is low relative to other phosphodiesterase 5 inhibitors.

Overview

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TL;DR

Tadalafil pharmacokinetics in healthy subjects are linear with respect to dose and time, with low oral clearance and a prolonged half-life. Food has negligible effect, and once-daily dosing reaches steady state by day 5 with approximately 1.6-fold accumulation.

Key findings

  • After a single 20-mg dose, mean Cmax was 378 µg l⁻¹ at median tmax 2 h; mean t₁/₂ was 17.5 h (5th, 95th percentiles 11.5, 29.6), CL/F was 2.48 l h⁻¹ (1.35, 4.35), and Vz/F was 62.6 l (39.5, 92.1).
  • Exposure was proportional to dose: doubling the dose increased AUC by 1.96-fold (1.90, 2.02), with β = 0.97 (0.93, 1.01); Cmax increased slightly less than proportionally, by 1.84-fold (1.77, 1.91).
  • Food had negligible effect: fed/fasted geometric mean ratios were 1.08 (1.02, 1.15) for AUC and 1.16 (1.07, 1.26) for Cmax, within prespecified equivalence limits. Evening/morning ratios were 0.81 (0.73, 0.90) for AUC and 0.79 (0.71, 0.89) for Cmax, suggesting slightly lower evening bioavailability.
  • With 10- or 20-mg once-daily dosing, steady state was attained by day 5; accumulation from day 1 to day 10 was approximately 1.6-fold, and day 10 t₁/₂, CL/F, and Vz/F were similar to single-dose values.

Methods

  • Noncompartmental pharmacokinetic parameters were calculated from 13 single-dose clinical pharmacology studies in healthy subjects; an integrated statistical analysis included 237 subjects (186 males), with 45 subjects contributing data from two dosing occasions, and assessed BMI, age, gender, and smoking status.
  • Three studies evaluated diurnal effects (12 subjects, 10 mg), definitive food effects (18 subjects, 20 mg fed vs fasted), and dose proportionality (16 subjects, single 2.5-, 5-, 10-, and 20-mg doses in a four-period crossover).
  • A separate multiple-dose study randomized 65 healthy subjects to 10 or 20 mg tadalafil once daily for 10 days; 30 subjects participated in the pharmacokinetic assessment. Plasma tadalafil was measured by validated HPLC-MS/MS, and analyses used mixed-effects models, a power model for dose proportionality, and prespecified equivalence confidence intervals.

Limitations

  • The paper states that absolute bioavailability of tadalafil following oral dosing has not been determined in any clinical study.
  • The paper states that the report does not address populations with erectile dysfunction, hypertension, diabetes, renal insufficiency, hepatic impairment, or CYP3A inducer/inhibitor drug interactions.
  • Evident from the text: the integrated analysis was in healthy volunteers who were predominantly Caucasian (228/237) and male (186/237), and several substudies were small (diurnal n = 12; food effect n = 18; dose proportionality n = 16), which limits generalizability.

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Integrity signals

Registry

Crossref · 10.1111/j.1365-2125.2005.02553.x

Cites

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Citations

Cites

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Research works printed but not linked: 5

  1. Ring BJ, 2004, Identification of the human cytochrome P450 (CYP) responsible for the formation of the major oxidative metabolite of tadalafil (Cialis), Drug Metab Rev, 36, 70
  2. Phillips DL, 2004, Metabolism and excretion of tadalafil in healthy men after oral administration of 100 mg [14C]‐tadalafil, The AAPS J, 6
  3. Patterson B, 2001, Dose‐normalized pharmacokinetics of tadalafil (IC351) administered as a single dose to healthy volunteers, Int J Impotence Res, 13, S32
  4. 2002, Guidance for Industry, Food‐Effect Bioavailability and Fed Bioequivalence Studies.
  5. Angulo J, 2001, IC351 enhances nitric oxide‐mediated relaxation of human arterial and trabecular penile smooth muscle, Diabetologia, 44, A295

Cited by

Items 101–200 of 285

Metadata

Authors
Forgue, S. T., Patterson, B. E., Bedding, A. W., Payne, C. D., Phillips, D. L., Wrishko, R. E., & Mitchell, M. I.
Affiliations
Eli Lilly (United States) (US)
Corresponding author
Forgue, S. Thomas
Venue
British Journal of Clinical Pharmacology
Publisher
Wiley
Published
2005-12-20
Volume
61
Issue
3
Pages
280-288
ISSN
  • 0306-5251 (ISSN-L)
  • 1365-2125
OpenAlex
W1975119053
Cited by
284
References
26
Citations by year
2026: 12 · 2025: 13 · 2024: 20 · 2023: 17 · 2022: 13 · 2021: 14 · 2020: 17 · 2019: 18 · 2018: 14 · 2017: 12 · 2016: 13 · 2015: 11 · 2014: 21 · 2013: 13 · 2012: 11
FWCI
5.31
Type
journal article
Language
en
Open access
Locations
  • British Journal of Clinical Pharmacology (publishedVersion)
  • PubMed (publishedVersion)
  • PubMed Central (publishedVersion)
Funders
Eli Lilly and Company
Topics
  • Health Sciences › Medicine › Psychiatry and Mental health › Sexual function and dysfunction studies
  • Life Sciences › Pharmacology, Toxicology and Pharmaceutics › Pharmacology › Pharmacogenetics and Drug Metabolism
  • Health Sciences › Medicine › Pediatrics, Perinatology and Child Health › Pharmaceutical studies and practices
Keywords
tadalafil, pharmacokinetics, phosphodiesterase-5 inhibitors, oral bioavailability, food effect, dose proportionality, steady-state pharmacokinetics, body mass index, smoking, age and gender effects, healthy volunteers
MeSH terms
Tadalafil, Adolescent, Adult, Aged, Biological Availability, Carbolines, Circadian Rhythm, Dose-Response Relationship, Drug, Drug Administration Schedule, Eating, Female, Humans, Male, Metabolic Clearance Rate, Middle Aged, Phosphodiesterase Inhibitors, Body Mass Index, Cross-Over Studies

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Data sources

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Contains information from the Semantic Scholar Academic Graph Datasets, made available under the ODC Attribution License (ODC-BY 1.0).

Semantic Scholar’s data is described in: Kinney, R., et al. (2023). The Semantic Scholar Open Data Platform. arXiv:2301.10140.