Can you take Cialis (tadalafil) with Imdur (isosorbide mononitrate)?

No, You Cannot Take Cialis with Imdur

The concurrent use of tadalafil (Cialis) with isosorbide mononitrate (Imdur) is absolutely contraindicated due to the risk of life-threatening hypotension. 1, 2

Why This Combination Is Dangerous

Mechanism of Severe Hypotension

• Both medications work through the nitric oxide pathway, causing profound and potentially fatal blood pressure drops when combined 1
• Tadalafil inhibits phosphodiesterase-5, which degrades cyclic guanosine monophosphate (cGMP), while nitrates like Imdur increase cGMP production through nitric oxide release 1
• This dual mechanism creates markedly exaggerated and prolonged vasodilation that can result in profound hypotension, myocardial infarction, stroke, or death 1

Required Waiting Periods

• Patients must wait at least 48 hours after the last dose of tadalafil before any nitrate can be safely administered 1, 2
• This extended waiting period is necessary because tadalafil has a half-life of 17.5 hours, meaning the active ingredient remains in the body for more than 2 days 1, 2
• For comparison, sildenafil and vardenafil require only 24 hours due to their shorter half-lives of approximately 4 hours 1

Clinical Implications

For Patients on Long-Acting Nitrates (Like Imdur)

• Patients taking long-acting nitrate therapy such as Imdur should not use tadalafil 1
• If a patient desires to use a phosphodiesterase-5 inhibitor, the decision must be guided by whether continued nitrate therapy is medically necessary versus available alternative treatments for their cardiac condition 1
• The treating clinician must evaluate if the patient's angina can be managed with non-nitrate alternatives (such as beta-blockers, calcium channel blockers, or ranolazine) before considering tadalafil 1

Emergency Situations

• If a patient taking tadalafil develops anginal chest pain requiring nitroglycerin, at least 48 hours must have elapsed since the last tadalafil dose 2
• In life-threatening situations where nitrate administration is deemed medically necessary despite recent tadalafil use, nitrates should only be given under close medical supervision with appropriate hemodynamic monitoring 2
• Patients experiencing chest pain after taking tadalafil should seek immediate medical attention and inform healthcare providers of their tadalafil use 2

Common Pitfalls to Avoid

• Do not assume the interaction only applies to short-acting nitroglycerin - all nitrate formulations including long-acting preparations like Imdur are contraindicated 1, 2
• Do not attempt dose reduction strategies - there is no safe dose of tadalafil that can be combined with nitrates 1, 2
• Do not confuse tadalafil's interaction profile with other antihypertensive medications - while tadalafil can be safely used with most blood pressure medications (including ACE inhibitors, calcium channel blockers, and beta-blockers with appropriate monitoring), nitrates remain an absolute contraindication 3, 4, 5

Alternative Management Strategies

For Erectile Dysfunction in Patients Requiring Nitrates

• Patients with chronic coronary disease requiring long-acting nitrate therapy must use non-pharmacologic approaches or alternative treatments for erectile dysfunction that do not interact with nitrates 1
• Vacuum erection devices, penile injections, or intraurethral suppositories may be considered as alternatives 1

For Angina in Patients Desiring Tadalafil

• Consider transitioning from nitrate therapy to alternative antianginal agents such as beta-blockers, calcium channel blockers, or ranolazine if clinically appropriate 1
• This decision requires careful cardiovascular risk assessment and should only be made if the patient's angina can be adequately controlled without nitrates 1