How long does Cialis (tadalafil) take to work?

How Long Does Cialis (Tadalafil) Take to Work

Cialis (tadalafil) begins working within 30 minutes after dosing, with significant erectogenic effects demonstrated as early as 16 minutes after taking the 20 mg dose. 1

Onset of Action

Tadalafil's onset of action varies based on dosage:

• Tadalafil 20 mg: Shows significant erectogenic response as quickly as 16 minutes after dosing 1
• Tadalafil 10 mg: Demonstrates significant erectogenic response from 26 minutes after dosing 1

In clinical trials measuring the earliest time to erectogenic effect:

• 52% of men taking tadalafil 20 mg had at least one successful intercourse attempt within 30 minutes compared to 35.1% of men taking placebo 1
• At the 24-hour timepoint, the mean percentage of attempts resulting in successful intercourse was 56% for tadalafil 10 mg and 67% for tadalafil 20 mg (compared to 42% for placebo) 2

Duration of Action

Tadalafil has a significantly longer duration of action compared to other PDE5 inhibitors:

• Extended effectiveness: Maintains efficacy for up to 36 hours after dosing 2, 3
• 36-hour timepoint: The mean percentage of successful intercourse attempts was 56% for tadalafil 10 mg and 62% for tadalafil 20 mg (compared to 33% for placebo) 2, 3

Factors Affecting Onset of Action

Several factors can influence how quickly Cialis works:

1. Food intake: High-fat meals may delay absorption and onset of action
2. Sexual stimulation: Required for the medication to work effectively 4
3. Incorrect use: Lack of sexual stimulation or taking with a large meal accounts for many treatment failures 4
4. Dose: Higher doses (20 mg) show faster onset of action than lower doses (10 mg) 1

Administration Options

Tadalafil is available in two administration regimens:

• On-demand (PRN) dosing: Taken before anticipated sexual activity
• Once-daily dosing: Lower doses (2.5-5 mg) taken daily regardless of timing of sexual activity 5

Important Precautions

1. Nitrate medications: Tadalafil should not be used concomitantly with nitrates due to risk of severe hypotension 4
2. Timing restrictions with nitrates: If a patient on tadalafil requires nitrates, they should wait at least 48 hours after the last tadalafil dose before nitrate administration 4
3. Hepatic/renal impairment: In patients with mild to moderate hepatic or renal impairment, tadalafil should be used with caution at lower doses 4

Clinical Pearls

• Patients should be counseled that sexual stimulation is necessary for tadalafil to work effectively 4
• More than one trial may be required to establish efficacy 4
• The long half-life of tadalafil (17.5 hours) contributes to its extended duration of action 4
• Patients should be informed that the medication may not work optimally on the first attempt

For optimal results, patients should be educated on proper use of tadalafil and understand that while effects may begin within 30 minutes, allowing more time before sexual activity may improve response rates.