GoodRx HealthFrom Birth Control to Blood Thinners: 9 Melatonin Interactions to Be Aware of

Understanding the diverse interactions between melatonin and various medications can help clinicians make informed decisions on its use for sleep aid, ensuring patient safety and treatment efficacy.

Melatonin is a commonly used over-the-counter supplement for improving sleep, yet it can interact with a variety of medications, leading to potential side effects and altered drug efficacy. This article details nine significant interactions between melatonin and other medications, highlighting the importance of consulting healthcare providers before combining melatonin with other treatments. Clinicians should be aware of these interactions to provide optimal care and mitigate risks for their patients.

Key Points:

1. Melatonin and Antidepressants: Certain antidepressants, including SSRIs like fluoxetine (Prozac) and citalopram (Celexa), can increase melatonin levels, potentially causing drowsiness, headaches, or upset stomach. Nortriptyline and fluvoxamine are particularly notable for this interaction.
2. Nifedipine Interaction: Melatonin can reduce the effectiveness of nifedipine, a calcium channel blocker used for hypertension, potentially leading to increased blood pressure.
3. Warfarin and Blood Thinners: Melatonin can enhance the effects of warfarin, increasing the risk of bleeding. Regular blood tests and monitoring are recommended when combining these medications.
4. Sedative Medications: Combining melatonin with other sedative substances like Benadryl, diazepam, opioids, alcohol, and cannabis can amplify drowsiness and impair cognitive functions.
5. Caffeine: Caffeine can increase melatonin levels due to its effect on liver enzymes, though this interaction is typically minor as melatonin is usually taken at bedtime when caffeine consumption is low.
6. Oral Contraceptives: Birth control pills can elevate melatonin levels, potentially increasing the likelihood of side effects. Starting with a low dose of melatonin is advisable.
7. Diabetes Medications: Melatonin may lower blood glucose levels, posing a risk for hypoglycemia when taken with diabetes medications. Close monitoring of blood glucose is necessary.
8. Blood Pressure Medications: Melatonin can lower blood pressure, potentially leading to hypotension when combined with antihypertensive drugs like beta blockers, ACE inhibitors, and diuretics.
9. Immunosuppressants: Melatonin can stimulate the immune system, possibly reducing the efficacy of immunosuppressant medications used in autoimmune conditions or post-organ transplant.

The use of melatonin is rising, with an increase in prevalence of use in the US in those 65 or older from 0.6% to 2.1% in the years from 1999 to 2018, and a similar trend in the UK. (Clinical Interventions in Aging)

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