PDE5 inhibitors, including ALYQ™, are mild systemic vasodilators. Clinical pharmacology studies were conducted to assess the effect of tadalafil on the potentiation of the blood–pressure–lowering effects of selected antihypertensive medications (amlodipine, angiotensin II receptor blockers, bendroflumethiazide, enalapril, and metoprolol). Small reductions in blood pressure occurred following coadministration of tadalafil with these agents compared with placebo [see Clinical Pharmacology (12.2)].
Both alcohol and tadalafil, a PDE5 inhibitor, act as mild vasodilators. When mild vasodilators are taken in combination, blood pressure–lowering effects of each individual compound may be increased. Substantial consumption of alcohol (e.g., 5 units or greater) in combination with ALYQ™ can increase the potential for orthostatic signs and symptoms, including increase in heart rate, decrease in standing blood pressure, dizziness, and headache. Tadalafil (10 mg or 20 mg) did not affect alcohol plasma concentrations and alcohol did not affect tadalafil plasma concentrations. [see Clinical Pharmacology (12.2)].
Ritonavir initially inhibits and later induces CYP3A, the enzyme involved in the metabolism of tadalafil. At steady state of ritonavir (about 1 week), the exposure to tadalafil is similar as in the absence of ritonavir [see Dosage and Administration (2.4) and Clinical Pharmacology (12.3)].
Potent Inhibitors of CYP3A
Tadalafil is metabolized predominantly by CYP3A in the liver. In patients taking potent inhibitors of CYP3A such as ketoconazole, and itraconazole, avoid use of ALYQ™ [see Clinical Pharmacology (12.3)].
Potent Inducers of CYP3A
For patients chronically taking potent inducers of CYP3A, such as rifampin, avoid use of ALYQ™ [see Clinical Pharmacology (12.3)].
Limited data from case series with tadalafil use in pregnant women have not identified a drug-associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes. In animal reproduction studies, no adverse developmental effects were observed with oral administration of tadalafil to pregnant rats or mice during organogenesis at exposures 7 times the exposure at the maximum recommended human dose (MRHD) of 40 mg/day based on AUC (see Data).
The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively.
Disease-Associated Maternal and/or Embryo/Fetal Risk
Pregnant women with untreated pulmonary arterial hypertension are at risk for heart failure, stroke, preterm delivery, and maternal and fetal death.
Tadalafil and/or its metabolites cross the placenta, resulting in fetal exposure in rats.
Animal reproduction studies showed no evidence of teratogenicity, embryotoxicity, or fetotoxicity when tadalafil was given to pregnant rats or mice at unbound tadalafil exposures up to 7 times the exposure at the maximum recommended human dose (MRHD) of 40 mg/day during organogenesis based on AUC. In one of two perinatal/postnatal developmental studies in rats, a reduction of postnatal pup survival was observed at dose levels of 60, 200 and 1000 mg/kg. The no-observed effect- level (NOEL) for developmental toxicity was 30 mg/kg, which provided maternal exposure to unbound tadalafil concentrations approximately 5 times the exposure at the MRHD based on AUC. Signs of maternal toxicity occurred at doses greater than 200 mg/kg/day, which produced AUCs greater than 8 times the exposure at the MRHD. Surviving offspring had normal development and reproductive performance.
There are no data on the presence of tadalafil and/or its metabolites in human milk, the effects on the breastfed child, or the effects on milk production. Tadalafil and/or its metabolites are present in the milk of lactating rats at concentrations approximately 2.4-times that found in the plasma. When a drug is present in animal milk, it is likely that the drug will be present in human milk.
The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for ALYQ™ and any potential adverse effects on the breastfed child from ALYQ™ or from the underlying maternal condition.
Based on the data from 3 studies in adult males, tadalafil decreased sperm concentrations in the study of 10 mg tadalafil for 6 months and the study of 20 mg tadalafil for 9 months. This effect was not seen in the study of 20 mg tadalafil taken for 6 months. There was no adverse effect of tadalafil 10 mg or 20 mg on mean concentrations of testosterone, luteinizing hormone or follicle stimulating hormone. The clinical significance of the decreased sperm concentrations in the two studies is unknown. There have been no studies evaluating the effect of tadalafil on fertility in men or women [see Clinical Pharmacology (12.2)].
Safety and effectiveness of ALYQ™ in pediatric patients have not been established.
Of the total number of subjects in the clinical study of tadalafil for pulmonary arterial hypertension, 28 percent were 65 and over, while 8 percent were 75 and over. No overall differences in safety were observed between subjects over 65 years of age compared to younger subjects or those over 75 years of age. No dose adjustment is warranted based on age alone; however, a greater sensitivity to medications in some older individuals should be considered. [See Clinical Pharmacology (12.3)].
For patients with mild or moderate renal impairment, start ALYQ™ at 20 mg once daily. Increase the dose to 40 mg once daily based upon individual tolerability [see Dosage and Administration (2.2) and Clinical Pharmacology (12.3)].
In patients with severe renal impairment, avoid use of ALYQ™ because of increased tadalafil exposure (AUC), limited clinical experience, and the lack of ability to influence clearance by dialysis [see Clinical Pharmacology (12.3)].
Because of limited clinical experience in patients with mild to moderate hepatic cirrhosis (Child-Pugh Class A or B), consider a starting dose of ALYQ™ 20 mg once daily. Patients with severe hepatic cirrhosis (Child-Pugh Class C) have not been studied, thus avoid use of ALYQ™ in such patients [see Dosage and Administration (2.3) and Clinical Pharmacology (12.3)].
Single doses up to 500 mg have been given to healthy male subjects, and multiple daily doses up to 100 mg have been given to male patients with erectile dysfunction. Adverse reactions were similar to those seen at lower doses. Doses greater than 40 mg have not been studied in patients with pulmonary arterial hypertension. In cases of overdose, standard supportive measures should be adopted as needed. Hemodialysis contributes negligibly to tadalafil elimination.
ALYQ™ (tadalafil, USP), an oral treatment for pulmonary arterial hypertension, is a selective inhibitor of cyclic guanosine monophosphate (cGMP)–specific phosphodiesterase type 5 (PDE5). The structural formula is:
C22 H19 N3 O4 M.W. 389.41
The chemical designation is pyrazino[1′,2′:1,6]pyrido[3,4-b]indole-1,4-dione, 6-(1,3-benzodioxol-5-yl)-2,3,6,7,12,12a-hexahydro-2-methyl-, (6R-12aR). It is a white to off-white crystalline solid that is practically insoluble in water and very slightly soluble in ethanol.
ALYQ™ is available as orange, film-coated, oval-shaped tablets for oral administration. Each tablet contains 20 mg of tadalafil, USP and the following inactive ingredients: croscarmellose sodium, iron oxide red, iron oxide yellow, lactose monohydrate, microcrystalline cellulose, polyethylene glycol, polyvinyl alcohol-part hydrolyzed, povidone, sodium lauryl sulfate, sodium starch glycolate, sodium stearyl fumarate, talc, and titanium dioxide.
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