Common Side Effects of Passion Flower
While generally considered safe for short-term use, passion flower (Passiflora incarnata) can cause a range of side effects, many of which are related to its sedative properties. These effects are often dose-dependent, meaning they can become more pronounced with higher doses.
- Drowsiness and Sedation: The most common side effect is sleepiness, which can impair the ability to drive or operate heavy machinery safely. This is the desired effect for those using it for sleep, but it can be problematic during daytime hours.
- Dizziness and Confusion: Users may experience a feeling of lightheadedness or a general sense of confusion and altered consciousness.
- Impaired Coordination (Ataxia): Some individuals may experience uncoordinated movements, difficulty with balance, or slurred speech.
- Gastrointestinal Distress: Mild stomach upset, nausea, and vomiting have been reported by some users.
- Mental Slowing: A feeling of being mentally sluggish or experiencing difficulty with concentration can occur, especially with higher doses.
Serious and Rare Side Effects
Although less common, more severe side effects can occur, particularly with higher doses, sensitive individuals, or pre-existing conditions.
- Cardiac Symptoms: While rare, there have been reports of heart rhythm disturbances associated with passion flower, including a prolonged QT interval and ventricular tachycardia (a rapid, irregular heartbeat). A case report detailed a patient with severe nausea, vomiting, drowsiness, and heart symptoms after self-administering passion flower. Individuals with pre-existing heart conditions should be especially cautious.
- Allergic Reaction: In some individuals, an allergic reaction can occur, with symptoms such as itching, rash, or difficulty breathing.
- Liver and Pancreas Toxicity: In very rare cases, liver and pancreas toxicity have been reported. While a specific link has not been conclusively established, combination products involving other herbs (like kava) have been associated with fatal liver injury.
Significant Drug Interactions
Passion flower can interact with several types of medications, potentially increasing their effects and causing dangerous complications. It is vital to consult a healthcare provider before combining passion flower with any prescription or over-the-counter drugs.
Interactions with Sedatives
Because of its potent sedative effects, combining passion flower with other central nervous system (CNS) depressants can cause excessive sleepiness, extreme sedation, and potentially slowed breathing. This includes:
- Benzodiazepines: Such as alprazolam (Xanax) and lorazepam (Ativan).
- Barbiturates: Including phenobarbital and butalbital.
- Hypnotics (Sleeping Pills): Such as zolpidem (Ambien).
- Antihistamines: Like diphenhydramine and cetirizine.
- Tricyclic Antidepressants: Such as amitriptyline (Elavil).
- Opioids: Including hydrocodone and oxycodone.
- Alcohol: Combining passion flower with alcohol can significantly increase drowsiness.
Interactions with Blood Thinners
Passion flower may slow blood clotting, which can increase the risk of bleeding when taken alongside blood-thinning medications. This includes:
- Anticoagulants: Such as warfarin (Coumadin).
- Antiplatelets: Such as aspirin and clopidogrel (Plavix).
Other Notable Interactions
- Blood Pressure Medications: Passion flower can lower blood pressure. Taking it with antihypertensive drugs like enalapril (Vasotec) or losartan (Cozaar) could cause blood pressure to drop too low.
- MAO Inhibitors: There is a theoretical risk that passion flower might increase the effects and dangerous side effects of this class of older antidepressants.
- Anesthesia: Due to its effect on the nervous system, passion flower should be stopped at least two weeks before any scheduled surgery to avoid interactions with anesthesia.
Who Should Avoid Taking Passion Flower?
Certain groups of people should not take passion flower due to potential risks.
- Pregnant and Breastfeeding Women: Passion flower is possibly unsafe during pregnancy as some of its compounds may induce uterine contractions. There is also insufficient data on its safety during breastfeeding.
- Individuals Undergoing Surgery: As mentioned, anyone scheduled for surgery should stop taking passion flower at least two weeks beforehand.
- Children Under 12: Though some specific products have been studied in older children, passion flower is generally not recommended for children under the age of 12.
- Individuals with Liver or Kidney Disease: Those with liver or kidney issues should use caution, given the potential for toxicity.
Passion Flower Side Effects: A Comparison Table
| Side Effect Category | Common Examples | Rare/Serious Examples | Specific Risk Factors |
|---|---|---|---|
| Neurological | Drowsiness, Dizziness, Confusion, Mental Slowing | Ataxia (impaired coordination), Central Nervous System (CNS) Depression | Dose-dependent; Increased risk with other CNS depressants. |
| Cardiovascular | Lowered blood pressure | Irregular heart rate, Prolonged QT interval, Ventricular tachycardia | Pre-existing heart conditions, Combination with blood pressure or heart rhythm medications. |
| Gastrointestinal | Nausea, Vomiting, Upset stomach | Potential Liver or Pancreas Toxicity | High doses; Combination with other herbs, especially kava. |
| Allergic | Rash, Itching, Difficulty breathing | Anaphylaxis (severe allergic reaction) | Pre-existing allergies to Passiflora plants. |
| Reproductive | Uterine contractions | Potential miscarriage, Adverse pregnancy outcomes | Pregnancy; Compounds in the plant may stimulate the uterus. |
Safe Usage and When to Consult a Doctor
Given the range of possible side effects and interactions, it is always best to consult with a healthcare professional before starting passion flower supplements. This is particularly important if you are taking any prescription medication, have a pre-existing medical condition, are pregnant, or are breastfeeding. Starting with a low dose and carefully monitoring your body's reaction can help minimize risks. Due to its sedative effects, avoid driving or operating heavy machinery until you are certain how it affects you.
For more detailed information on passion flower and other herbal supplements, consider visiting the National Center for Complementary and Integrative Health (NCCIH), a division of the National Institutes for Health, which provides science-based information on complementary and alternative medicine. https://www.nccih.nih.gov/health/passionflower.
Conclusion
Passion flower is a popular herbal remedy with documented calming effects that can benefit anxiety and sleep. However, the potential for side effects, from common issues like drowsiness and dizziness to rare but serious cardiac complications, should not be overlooked. Its significant interactions with various medications, particularly sedatives and blood thinners, require careful consideration and medical supervision. For populations like pregnant women, those undergoing surgery, and individuals with heart conditions, avoidance is often recommended. By understanding the potential risks and seeking professional guidance, you can make an informed decision about whether passion flower is a safe option for you.
