Influence of polymorphisms of adenosine A2 receptor and dopamine D2 receptor on mental calculations, blood pressure and pulse rate after intake of caffeine: a double-blind randomized placebo-controlled clinical trial.

Influence of polymorphisms of adenosine A2 receptor and dopamine D2 receptor on mental calculations, blood pressure and pulse rate after intake of caffeine: a double-blind randomized placebo-controlled clinical trial. - Influence of polymorphisms of adenosine A2 receptor and dopamine D2 receptor on the effect of caffeine

Status

Active, not recruiting

Phases

Unknown

Study type

Interventional

Source

JPRN

Registry ID

JPRN-UMIN000010360

Enrollment

500

Registered

2013-04-01

Start date

2013-04-01

Completion date

Unknown

Last updated

2026-06-29

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Effect of caffeine

Interventions

intake coffee 150 mL with caffeine 200mg intake coffee 150 mL without caffeine

Eligibility

Sex/Gender

All

Inclusion criteria

Inclusion criteria: Healthy adult volunteers

Exclusion criteria

Exclusion criteria: 1. cardiovascular disease that should be treated 2. severe liver disease 3. severe renal disease 4. pregnant women and women suspected of being pregnant 5. severe allergic reaction and allergic reaction to caffeine 6. gastric ulcer 7. glaucoma 8. On medical treatment 9. Not appropriate to this study by other reasons

Design outcomes

Primary

Measure	Time frame
Change of the accurate number of mental calculation after intake caffeine 200 mg compared to decafe	—

Secondary

Measure	Time frame
Change of blood pressure and pulse rate after intake caffeine 200 mg compared to decafe	—

Countries

Japan

Contacts

Public ContactTatsuya Yoshihara

Faculty of Medical Sciences, Kyushu University Department of Clinical Pharmacology

tatsuya@clipharm.med.kyushu-u.ac.jp+81-92-642-6082

Outcome results

None listed

Source: JPRN (via WHO ICTRP) · Data processed: Jul 3, 2026