From the Guidelines
I strongly advise against combining THC and tadalafil without medical supervision due to the potential for dangerous interactions that could lead to significant drops in blood pressure. When considering the use of THC and tadalafil together, it's crucial to understand the mechanisms by which both substances affect blood pressure. Tadalafil, a PDE5 inhibitor, is known for its vasodilatory effects, which can lower blood pressure, and it is commonly used for treating erectile dysfunction and pulmonary hypertension [ 1 ]. On the other hand, THC, the psychoactive component of cannabis, also has vasodilatory properties, which can further contribute to a decrease in blood pressure.
The potential for these substances to interact and cause significant hypotension is a concern, especially when considering the prolonged action of tadalafil, which can remain active in the system for up to 36 hours [ 2 ]. This prolonged window increases the risk of adverse interactions, particularly if other medications such as nitrates, alpha-blockers, or antihypertensives are also being used.
Key considerations for managing erectile dysfunction (ED) include assessing cardiovascular risk and ensuring that any treatment for ED does not negatively impact cardiovascular health [ 1 ]. Given the potential risks associated with combining THC and tadalafil, it is essential to prioritize caution and consult with a healthcare provider before using these substances together. This approach allows for a personalized assessment of the risks and benefits and helps in monitoring for any adverse effects, particularly on blood pressure.
In clinical practice, the management of ED should always consider the patient's overall health, including cardiovascular risk factors [ 2 ]. The use of PDE5 inhibitors like tadalafil is a common approach for treating ED, but it requires careful consideration of potential interactions with other substances, including THC. By prioritizing patient safety and taking a cautious approach to the use of these substances, healthcare providers can help minimize risks and optimize outcomes for individuals with ED.
From the Research
THC and Tadalafil Interaction
- There is limited research directly addressing the interaction between THC and tadalafil.
- However, studies have shown that THC can interact with various medications due to its effects on cytochrome P450 hepatic isoenzymes 3.
- Tadalafil, a phosphodiesterase-5 (PDE-5) inhibitor, is metabolized by CYP3A4, which can be impacted by THC 3.
- The interaction between THC and tadalafil may lead to increased levels of tadalafil in the body, potentially increasing the risk of adverse effects such as hypotension, priapism, or other cardiovascular events 3, 4.
Tadalafil and Erectile Dysfunction
- Tadalafil is commonly used to treat erectile dysfunction (ED) and has been shown to be effective in improving erectile function in men with ED 5, 6.
- A study published in The American Journal of Medicine found that tadalafil was associated with significantly reduced risks of all-cause mortality, myocardial infarction, stroke, venous thromboembolism, and dementia in men with ED 5.
- Another study published in Sexual Medicine Reviews found that combination therapy with tadalafil and other medications may be effective in treating ED in patients who do not respond to PDE-5 inhibitor monotherapy 6.
THC and Cardiovascular Effects
- THC has been shown to have cardiovascular effects, including increased heart rate and blood pressure, which may be problematic for individuals with pre-existing cardiovascular conditions 7.
- A review published in The New Zealand Medical Journal found that long-term use of THC can result in respiratory and cardiovascular toxicity, and has been associated with a range of psychiatric conditions 7.
- Another review published in the Journal of Clinical Pharmacology found that cannabis may interact with anticoagulant and antiplatelet agents, potentially causing harmful drug-drug interactions and increasing the risk of cardiovascular events 4.