Tadalafil in the Treatment of Erectile Dysfunction: ADVERSE DRUG REACTIONS

In: Drug

26 May 2010

Causes a variety of adverse reactions. Nearly all patients in the clinical trials experienced one or more adverse events. The most commonly reported adverse reactions were headache, dyspepsia, back pain, myalgia, nasal congestion, flushing, and painful limbs.


Coadministration of Nitrates and Alpha Blockers Concomitant administration of tadalafil and organic nitrates, either regularly or intermittently, is contraindicated. Tadalafil exacerbates the hypotensive effect of nitrates in clinical studies, presumably as a result of the combined effects of both agents on the NO/cGMP pathway.

Simultaneous administration of tadalafil and the alpha-adrenergic antagonists, except for 0.4 mg once-daily tamsulosin (Boehringer Ingelheim), is contraindicated. In a study of drug-drug interactions, 20 mg of tadalafil was administered to healthy subjects taking 8 mg of mesylate (Pfizer) daily. A significant increase in the blood pressure-lowering effect of doxazosin canadian was observed.

Extended-Duration Erections and Priapism

In rare instances, PDE5 inhibitors have been associated with erections lasting longer than four hours and with pri-apism, a persistent abnormal penile erection, accompanied by pain and tenderness. If priapism is not treated in a timely manner, irreversible damage to the erectile tissue can occur. If an erection lasts more than four hours, whether or not it is painful, the patient should seek emergency medical attention.

Renal and Hepatic Disorders

Before prescribing tadalafil tablet, health care providers should note any history or presence of renal insufficiency or hepatic impairment. For men with mild or moderate renal insufficiency, their tadalafil concentrations doubled. Following a single dose of 10 or 20 mg, men with end-stage renal disease who were undergoing hemodialysis experienced a 2.7fold to 4.1-fold increase in area-under-the curve (AUC) concentration and a twofold increase in maximum concentration. Several precautions apply:

• For patients with severe renal insufficiency or end-stage renal disease, the tadalafil dose should be limited to 5 mg no more than once daily.
• For patients with moderate renal insufficiency, a starting dose of 5 mg, taken not more than once daily, is recommended. The maximum dose should be 10 mg, to be taken not more than once in 48 hours.
• For patients with mild renal insufficiency, no dosage adjustment is required.

For patients with mild or moderate hepatic impairment, tadalafil exposure (AUC) after a 10-mg dose was comparable to exposure in healthy subjects. Because no data are available for doses higher than 10 mg in patients with hepatic impairment, the maximum dose should not exceed 10 mg for these men.

For patients with severe hepatic impairment, tadalafil is not recommended because the data are insufficient.


Tadalafil is the newest agent to be approved by the FDA for the treatment of ED. The recommended starting dose for most patients is 10 mg, to be taken before anticipated sexual activity. The dose may be increased to 20 mg or decreased to 5 mg, depending on the agent’s efficacy and the patient’s tolerability. For most patients, the maximum dosing frequency is once a day.

Unlike other available treatments, tadalafil may enable a patient to take a pill on a Friday evening and have intercourse with his partner on a Saturday night or a Sunday morning. This extended period of responsiveness afforded by tadalafil canadian may lead to a new treatment paradigm for
men with ED.

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