Adult: Initially, 10 mg as needed, at least 30 min before sexual intercourse, may be increased to 20 mg, depending on response. Alternatively, 5 mg once daily, taken at the same time each day, may be decreased to 2.5 mg, depending on response. Max dosing frequency: Once every 24 hr.
Oral Benign prostatic hyperplasia
Adult: 5 mg once daily, taken at the same time each day.
Oral Pulmonary arterial hypertension
Adult: 40 mg once daily.
Special Patient Group
Benign prostatic hyperplasia: Patients taking CYP3A4 inhibitors (e.g. azole antifungals and protease inhibitors): Max: 10 mg once every 72 hr, as needed.
Erectile dysfunction: Patients taking CYP3A4 inhibitors (e.g. azole antifungals and protease inhibitors): Max: 2.5 mg once every 24 hr.
Pulmonary arterial hypertension: Patients taking ritonavir or other HIV protease inhibitors: 20 mg once daily, increased to 40 mg once daily as tolerated.
Erectile dysfunction: Patient on haemodialysis: Max: 5 mg once every 72 hr; regular daily dosing is not recommended.
Max: 5 mg once every 72 hr; regular daily dosing is not recommended.
Initially, 5 mg once daily. Max: 10 mg once every 48 hr.
Benign prostatic hyperplasia: Patient on haemodialysis: Not recommended.
Initially, 2.5 mg once daily. Max: 5 mg.
Pulmonary arterial hypertension:
Initially, 20 mg once daily, increased to 40 mg once daily, according to tolerability.
Erectile dysfunction: Mild to moderate (Child-Pugh class A or B): Max: 10 mg once daily, as needed. Severe (Child-Pugh class C): Not recommended.
Benign prostatic hyperplasia: Severe (Child-Pugh class C): Not recommended.
Pulmonary arterial hypertension: Mild to moderate (Child-Pugh class A or B): Initially, 20 mg once daily. Severe (Child-Pugh class C): Contraindicated.
May be taken with or without food.
Hypotension, mild to severe heart failure, acute recent MI; other conditions wherein sexual activity is inadvisable; recent stroke, uncontrolled arrhythmias and/or HTN, unstable angina, vision loss due to non-arteritic anterior ischaemic optic neuropathy (NAION). Severe hepatic impairment (Child-Pugh class C) when used for pulmonary arterial hypertension. Concomitant use of any form of organic nitrates, nitric oxide donors, and guanylate cyclase stimulators.
Patient w/ retinitis pigmentosa, left ventricular outflow obstruction (aortic stenosis or hypertrophic obstructive cardiomyopathy), anatomical penile deformation, conditions which may be predisposed to priapism (e.g. sickle cell anaemia, multiple myeloma, leukemia); bleeding disorders, peptic ulcer disease, pulmonary veno-occlusive disease. Renal and hepatic impairment. Pregnancy and lactation.
Description: Tadalafil is a phosphodiesterase inhibitor w/ the greatest selectivity for PDE type 5, which is responsible for the metabolism of cyclic guanosine monophosphate (cGMP) in the smooth muscle. Inhibition leads to: increase in cGMP levels causing smooth muscle relaxation and increased blood flow into the corpus cavernosum of the penis during sexual stimulation thereby producing an erection; relaxation of smooth muscle in the pulmonary vascular bed causing vasodilation and reduction in pulmonary vascular resistance; relaxation of smooth muscle or increased blood perfusion in the bladder and prostate. Onset: W/in 1 hr. Pulmonary artery vasodilation: 75-90 min. Duration: Erectile dysfunction: Up to 36 hr. Pharmacokinetics: Absorption: Well absorbed from the GI tract. Time to peak plasma concentration: Approx 2 hr (range: 30 min to 6 hr). Distribution: Widely distributed in the tissues. Detected in the semen. Volume of distribution: 63-77 L. Plasma protein binding: Approx 94%. Metabolism: Metabolised in the liver primarily by CYP3A4 via methylation and glucuronidation to form inactive metabolites methylcatechol and methylcatechol glucuronide respectively. Excretion: Mainly via faeces (approx 61%, as metabolites); urine (lesser extent, approx 36%, as metabolites). Elimination half-life: 15-17.5 hr.
G04BE08 - tadalafil ; Belongs to the class of drugs used in erectile dysfunction.
Anon. Tadalafil. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 11/10/2017.Buckingham R (ed). Tadalafil. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 11/10/2017.Cialis Tablet, Film Coated (Eli Lilly and Company). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 11/10/2017.Joint Formulary Committee. Tadalafil. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 11/10/2017.McEvoy GK, Snow EK, Miller J et al (eds). Tadalafil. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 11/10/2017.