Torfil 2.5/Torfil 10/Torfil 20 Drug Interactions

Antacids: Concomitant use of antacids (e.g., Magnesium hydroxide and/or Aluminum hydroxide) and tadalafil reduces the rate of absorption of tadalafil without modifying tadalafil exposure.
H2 Antagonists: Use of H2 antagonist has no significant effect on the pharmacokinetics of tadalafil; Co-administration of Tadalafil and Nizatidine reduces the gastric pH.
Nitrates: Torfil 2.5: Administration of Tadalafil is contraindicated in patients who are taking any form of organic nitrates as it is known to increase the hypotensive effects of the nitrate. In a patient whose taken tadalafil, where administration of nitrate is deemed medically necessary in a life-threatening situation, at least 48 hours should elapse after the last dose of Tadalafil before nitrate administration is considered.
Torfil 10/Torfil 20: Concomitant use of tadalafil with any other organic nitrates is contraindicated as it may augment hypotensive effects of nitrates.
Warfarin: There is no significant effect on the exposure to warfarin nor did tadalafil affect changes in the prothrombin time induced by warfarin.
HIV protease inhibitor: Torfil 2.5: Ritonavir, an inhibitor of CYP 3A4, CYP2C9, CYP2C19, and CYP2D6, increased tadalafil exposure. Other HIV protease inhibitors would likely increase tadalafil exposure.
Torfil 10/Torfil 20: HIV protease inhibitors such as saquinavir, erythromycin, and itraconazole would likely decrease tadalafil exposure.
Aspirin: Tadalafil did not potentiate the increase in bleeding time caused by aspirin.
Antihypertensives: Torfil 2.5: PDE5 inhibitors, including tadalafil, are mild vasodilators. Tadalafil potentiates the blood pressure-lowering effects of selected antihypertensive agents (e.g., amlodipine, angiotensin II receptor blockers, enalapril, and metoprolol) and small reduction in blood pressure occurred.
Torfil 10/Torfil 20: Co-administration of tadalafil with alpha-adrenergic receptor blockers may augment blood pressure lowering effects of anti-hypertensive agents (e.g. doxazosin) which may lead to systemic hypotension.
Alcohol: Torfil 2.5: 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 Tadalafil can increase the potential for orthostatic signs and symptoms, including increase in heart rate, decrease in standing blood pressure, dizziness, and headache. Tadalafil did not affect alcohol plasma concentration and alcohol did not affect tadalafil plasma concentrations.
Torfil 10/Torfil 20: Tadalafil has no effect in the alcohol concentration and vice versa. Postural dizziness and orthostatic hypotension were observed but can be prevented my reducing dose of alcohol.
Theophylline: Tadalafil has no significant effect on the pharmacokinetics and pharmacodynamics of theophylline.
Torfil 2.5: Cytochrome P450 Inhibitors: Tadalafil is predominantly metabolized in the liver by CYP3A4. CYP 3A4 inhibitors (e.g., Ketoconazole, erythromycin, itraconazole, and grapefruit juice) increases tadalafil exposure.
Cytochrome P450 Inducers: Co-administration with CYP3A4 inducers (e.g., Rifampicin, carbamazepine, phenytoin and phenobarbital) reduces tadalafil exposure.
Midazolam and Lovastatin: Tadalafil had no significant effect on exposure to midazolam and lovastatin.
P-glycoprotein (e.g., Digoxin): Tadalafil had no significant effect on the pharmacokinetics of digoxin.
Torfil 10/Torfil 20: CYP3A4 Inhibitors: Co-administration with CYP3A4 inhibitors such as ketoconazole, ritonavir, saquinavir, erythromycin, and itraconazole increases tadalafil exposure.
CYP3A4 Inducers: Co-administration with CYP3A4 inducers (e.g. Rifampicin) reduces tadalafil exposure.