Sexual Health & Vascular

Tadalafil / Cialis

PDE5 Inhibitor with unique 17.5-hour half-life. The "Weekend Pill" property allows for steady-state plasma concentrations with daily low-dose administration, offering 24/7 therapeutic coverage.

Functional Profile

Tadalafil is a selective phosphodiesterase type 5 (PDE5) inhibitor. Unlike Sildenafil (Viagra), Tadalafil boasts a unique pharmacokinetic profile characterized by a 17.5-hour half-life. This "Weekend Pill" property allows for steady-state plasma concentrations with daily low-dose administration, offering 24/7 therapeutic coverage.

Target Indications
ED, BPH (Lower Urinary Tract Symptoms), Pulmonary Arterial Hypertension.
Functional Uses
Endothelial Health, Nitric Oxide Optimization, "Gym Pumps", Estrogen Modulation.

Kinetics

HALF-LIFE 17.5 hrs
T-MAX (Peak) 2.0 hrs
STEADY STATE Day 5

Dosing Protocols

Standard Daily Dose
2.5 - 5 mg
Accumulates to 1.6x concentration
Timing

Take at the same time every day. Effect is continuous regardless of timing relative to sexual activity.

Clinical Goal

Spontaneity, BPH symptom relief, endothelial function improvement.

PEARL Lower side effect profile (headache/flushing) compared to on-demand high doses due to lower peak plasma concentrations.

Pharmacokinetics (20mg)

Single Dose
● Tadalafil vs ● Sildenafil

↺ Cycling & Washout

1
The 5-Day Rule

Due to the 17.5h half-life, it takes ~4-5 days for Tadalafil to fully clear the system (<5%).

2
When to Cycle Off?

If "Back Pump" or myalgia becomes persistent. Take a 5-7 day break to reset.

CRITICAL: Wait 48+ hours after last dose before nitrate administration.

The "Back Pump"

Common

Lower back myalgia due to PDE11 inhibition in skeletal muscle. Often mimics kidney pain.

RX: Taurine (2-3g), Hydration.

Reflux / GERD

Mech

PDE5 inhibition relaxes the Lower Esophageal Sphincter (LES), allowing acid reflux.

RX: Take with food, stay upright.

Blue Vision

Rare

Less common than Sildenafil. Caused by cross-reaction with PDE6 in the retina.

RX: Stop and reduce dose.