From the Guidelines
Trazodone (50 mg) and doxazosin (8 mg) can be taken together, but caution is advised due to potential interactions. Both medications can lower blood pressure, and when combined, this effect may be enhanced, potentially causing dizziness, lightheadedness, or fainting, especially when standing up quickly. According to the American Academy of Sleep Medicine clinical practice guideline 1, trazodone is not recommended as a treatment for sleep onset or sleep maintenance insomnia, which may be relevant when considering its use in combination with other medications. The guideline suggests that clinicians not use trazodone as a treatment for sleep onset or sleep maintenance insomnia (versus no treatment) in adults, based on trials of 50 mg doses of trazodone. However, this does not directly address the safety of combining trazodone with doxazosin.
The AUA guideline on management of benign prostatic hyperplasia 1 provides information on the use of doxazosin, stating that it is an appropriate treatment option for patients with LUTS secondary to BPH, and that the primary adverse events reported with alpha-blocker therapy are orthostatic hypotension, dizziness, tiredness, ejaculatory problems, and nasal congestion. Given this information, it is essential to monitor for symptoms of low blood pressure when starting this combination or when doses are adjusted. Taking doxazosin at bedtime can help minimize orthostatic hypotension (blood pressure drop when standing). If severe dizziness, fainting, or other concerning symptoms occur, it is crucial to contact a healthcare provider immediately. The interaction between trazodone and doxazosin occurs because doxazosin is an alpha-blocker that relaxes blood vessels, while trazodone has alpha-blocking properties as well. Always informing all healthcare providers about all medications being taken can help avoid potential drug interactions.
Key considerations when taking trazodone and doxazosin together include:
- Monitoring for symptoms of low blood pressure
- Taking doxazosin at bedtime to minimize orthostatic hypotension
- Informing all healthcare providers about all medications being taken
- Being aware of the potential for enhanced blood pressure-lowering effects and taking precautions to avoid dizziness, lightheadedness, or fainting.
From the Research
Interaction between Trazodone and Doxazosin
- The interaction between trazodone (50 mg) and doxazosin (8 mg) is not directly addressed in the provided studies.
- However, it is known that trazodone can cause orthostatic hypotension as a side effect 2.
- Doxazosin, an alpha 1-adrenoceptor antagonist, is also known to cause orthostatic hypotension, although it is reported to be infrequent 3, 4.
- The combination of two drugs that can cause orthostatic hypotension may increase the risk of this side effect.
- A study on the combination of trazodone and phenothiazines reported an additive hypotensive effect 2, which suggests that combining trazodone with another drug that can lower blood pressure may increase the risk of hypotension.
Pharmacology of Doxazosin
- Doxazosin is a selective alpha 1-adrenoceptor antagonist that is used to treat hypertension 3, 4, 5.
- It is known to decrease blood pressure by reducing peripheral resistance 3.
- The maximum hypotensive effects of doxazosin occur four to eight hours after the dose 3.
- Doxazosin has a favorable effect on serum lipids, increasing high-density lipoprotein (HDL) cholesterol and decreasing low-density lipoprotein (LDL) cholesterol and triglycerides 3, 4.
Pharmacology of Trazodone
- Trazodone is a triazolepyridine derivative that is used to treat depression 2.
- It has little catecholamine potentiation or anticholinergic action 2.
- Trazodone can cause orthostatic hypotension, although it is usually mild or transient 2.
- The combination of trazodone with other drugs that can cause hypotension may increase the risk of this side effect 2, 6.