Tadalafil (Cialis)

Overview

Tadalafil is a phosphodiesterase type 5 (PDE5) inhibitor used primarily for the treatment of erectile dysfunction and benign prostatic hyperplasia. It works by relaxing smooth muscle and increasing blood flow to specific areas of the body. The medication is not indicated for use in females.

Mechanism of Action

Tadalafil selectively inhibits phosphodiesterase type 5 (PDE5), which increases cyclic guanosine monophosphate (cGMP) levels. This leads to smooth muscle relaxation and vasodilation in the corpus cavernosum of the penis and prostate/bladder vasculature, improving erectile function and urinary symptoms.

Indications

Treatment of erectile dysfunction
Treatment of benign prostatic hyperplasia (BPH) symptoms
Treatment of both erectile dysfunction and BPH when conditions coexist

Common Doses

2.5 mg
5 mg
10 mg
20 mg

Dosage

Do not split Tadalafil tablets; entire dose should be taken. For erectile dysfunction: 10 mg taken prior to anticipated sexual activity, may be increased to 20 mg or decreased to 5 mg based on efficacy and tolerability. For daily use: 2.5-5 mg once daily. For BPH: 5 mg once daily.

Contraindications

Concomitant use with nitrates or nitric oxide donors
Hypersensitivity to tadalafil or any component of the formulation
Patients with cardiac conditions where sexual activity is inadvisable

Side Effects

Headache
Dyspepsia
Back pain
Myalgia
Nasal congestion
Flushing
Dizziness
Visual disturbances
Hypotension

Interactions

Nitrates (contraindicated - severe hypotension)
Alpha-blockers (caution - additive hypotension)
Strong CYP3A4 inhibitors (reduce tadalafil dose)
Alcohol (may increase hypotensive effects)
Antihypertensives (additive blood pressure lowering)

Counseling Points

Take as directed; do not split tablets
Avoid concurrent use with nitrates
Seek immediate medical attention for erection lasting >4 hours
Report sudden vision or hearing changes
Limit alcohol consumption
Take at least 30 minutes before sexual activity for as-needed dosing