Tadalafil interactions with other drugs

what are the Tadalafil interactions with other drugs

1. (1) AUC of sildenafil combined with CYP450 3A4 inhibitors (such as ketoconazole, itraconazole, red mold) and non-specific inhibitors of CYP450 (such as cimetidine) High and the clearance rate is reduced.
(2) combined with HIV protease inhibitors [such as saquinavir, ritonavir], cmax and AUC increased in sildenafil, and steady-state drugs in saquinavir and ritonavir The movement is not affected.
(3) Combined with loop diuretics, potassium-sparing diuretics and non-selective beta blockers, the AUC of the active metabolite of sildenafil (N-desmethylsildenafil) is increased by 62 % and 102%, but this effect is not clinically significant. (4) Combination with an inducer of CYP4503A4 (such as rifampicin) may reduce sildenafil plasma levels.
(5) No significant interaction was observed when combined with CYP450 2C9 inhibitors (such as tolbutamide, warfarin). (6) and CYP450 2D6 enzyme inhibitors (such as selective serotonin reuptake inhibitors, tricyclic antidepressants), thiazides and thiazide diuretics, angiotensin converting enzyme inhibitors, calcium channels The combination of blockers and the like has no effect on the pharmacokinetics of sildenafil.
2. Hypertensive patients taking sildenafil (100mg) and amlodipine (5mg or 10mg), the supine systolic blood pressure was further reduced by 1.06kPa (8mmHg), and the diastolic blood pressure was further reduced by 0.93kPa (7mmHg).
3. In combination with alpha blockers (such as doxazosin), it may cause hypotension in some patients. Therefore, if the dose of sildenafil exceeds 25 mg, it should not be taken within 4 hours of taking alpha blockers.
4. When combined with organic nitrates, sildenafil can inhibit PDE5 and thus affect the degradation of cGMP, which may cause extreme blood pressure drop and should be prohibited.
5. In vitro experiments showed that sildenafil enhanced the anti-human platelet aggregation of sodium nitroprusside.
6. Combined with heparin, it has a superimposed effect on the prolongation of bleeding time in anesthetized rabbits, but no similar human studies have been conducted.
7. In combination with aspirin, there is no effect on bleeding time.
8. A single dose of antacid (magnesium hydroxide or aluminum hydroxide) has no effect on the bioavailability of sildenafil. Drug-alcohol/nicotine interaction studies have shown that sildenafil (50 mg) does not enhance the antihypertensive effect of alcohol when the average maximum plasma alcohol concentration in healthy volunteers is 0.08%. Drug-food interactions High-fat diets reduced the rate of absorption of sildenafil, with an average delay of 60 min in peak time and an average decrease of 29% in Cmax.

Since other PDE5 inhibitors, Tadalafil may cause transient hypotension (low blood pressure), so the last dose of tadalafil should not be taken after an alkyl nitrite (Popper) at least 48 hours. Use poppers (amyl nitrate drugs such as sulfoxide) within this time may increase the risk of life-threatening hypotension.

Since taking tadalafil can not take organic nitrates to relieve angina (such as glyceryl trinitrate spray), these patients if angina occurs, should immediately seek medical treatment in the past 48 hours. In the event of a medical emergency, the healthcare provider and medical staff should be informed of the dose of the latest tadalafil.

Tadalafil is mainly metabolized by the liver CYP3A4 enzyme system. The presence of another drug-induced system can be shortened half-lives and reduced tadalafil serum levels of the drug, reducing its efficacy.

Related Articles ：Important information for Tadalafil 

• What is the dosage for Tadalafil?, what should I pay attention to?
• Tadalafil VS Sildenafil effect which is better
• Precautions for the use of tadalafil
• Tadalafil Pharmacological action and mechanism of action