Background

Ilex guayusa is a tree native to South America. Its leaves are consumed as a beverage in rituals. It's also used in traditional medicine.

Ilex guayusa contains caffeine. It also contains chemicals that might have antioxidant and antibacterial effects.

People sometimes use Ilex guayusa for memory and thinking skills, diabetes, and many other conditions, but there is no good scientific evidence to support these uses.

Don't confuse Ilex guayusa with caffeine or other caffeine-containing ingredients, including black tea, green tea, oolong tea, coffee, coffee charcoal, green coffee, cola nut, guarana, or yerba mate. These are not the same.

Safety Safety definitions

When taken by mouth: Ilex guayusa is commonly consumed as a beverage. But there isn't enough reliable information to know if Ilex guayusa is safe when used in larger amounts as medicine. Ilex guayusa also contains caffeine, which may cause side effects at high doses.

Special Precautions & Warnings:

Pregnancy and breast-feeding: There isn't enough reliable information to know if Ilex guayusa is safe to use when pregnant or breast-feeding. Stay on the safe side and avoid use.

Anxiety disorders: The caffeine in Ilex guayusa might make anxiety worse.

Bleeding disorders: The caffeine in Ilex guayusa might slow blood clotting and make bleeding disorders worse.

Heart disease: The caffeine in Ilex guayusa might cause irregular heartbeat in certain people. Use with caution.

Diabetes: The caffeine in Ilex guayusa might affect blood sugar. Use Ilex guayusa with caution if you have diabetes.

Diarrhea: The caffeine in Ilex guayusa, especially when taken in large amounts, can worsen diarrhea.

Seizures: Ilex guayusa contains caffeine. People with epilepsy should avoid using caffeine in high doses. Low doses of caffeine should be used cautiously.

Glaucoma: The caffeine in Ilex guayusa increases the pressure inside the eye. The increase occurs within 30 minutes and lasts for at least 90 minutes after consuming caffeine.

High blood pressure: The caffeine in Ilex guayusa might increase blood pressure in people with high blood pressure. But this doesn't seem to occur in people who consume caffeine regularly.

Loss of bladder control: Ilex guayusa contains caffeine. Caffeine can make bladder control worse by increasing the need and the urge to urinate.

Irritable bowel syndrome (IBS): Ilex guayusa contains caffeine. The caffeine in Ilex guayusa, especially when taken in large amounts, may worsen diarrhea and other symptoms of IBS.

Thinning bones (Osteoporosis): The caffeine in Ilex guayusa can flush calcium out of the body through the kidneys. This calcium loss might weaken bones. If you have osteoporosis, don't consume more than 300 mg of caffeine daily. But if you are generally healthy and getting enough calcium from your food or supplements, taking up to 400 mg of caffeine daily doesn't seem to increase the risk of getting osteoporosis.

Effectiveness

Dosing & administration

There isn't enough reliable information to know what an appropriate dose of Ilex guayusa might be. Keep in mind that natural products are not always necessarily safe and dosages can be important. Be sure to follow relevant directions on product labels and consult a healthcare professional before using.

Interactions with pharmaceuticals

Adenosine (Adenocard)

Interaction Rating=Moderate Be cautious with this combination.

The caffeine in Ilex guayusa might block the effects of adenosine, which is used to do a test called a cardiac stress test. Stop consuming Ilex guayusa or other caffeine-containing products at least 24 hours before a cardiac stress test.

Alcohol (Ethanol)

Interaction Rating=Minor Be watchful with this combination.

The body breaks down the caffeine in Ilex guayusa to get rid of it. Alcohol can decrease how quickly the body breaks down caffeine. Taking Ilex guayusa along with alcohol might increase the risk of caffeine side effects including jitteriness, headache, and fast heartbeat.

Antibiotics (Quinolone antibiotics)

Interaction Rating=Minor Be watchful with this combination.

The body breaks down caffeine from Ilex guayusa to get rid of it. Some drugs can decrease how quickly the body breaks down caffeine. Taking these drugs along with Ilex guayusa might increase the risk of caffeine side effects including jitteriness, headache, and fast heartbeat.

Birth control pills (Contraceptive drugs)

Interaction Rating=Moderate Be cautious with this combination.

Ilex guayusa contains caffeine. The body breaks down caffeine to get rid of it. Birth control pills can decrease how quickly the body breaks down caffeine. This might increase the risk for side effects from caffeine, such as jitteriness, headache, and fast heartbeat.

Cimetidine (Tagamet)

Interaction Rating=Moderate Be cautious with this combination.

The body breaks down the caffeine in Ilex guayusa to get rid of it. Cimetidine can decrease how quickly the body breaks down caffeine. Taking cimetidine along with Ilex guayusa might increase the chance of caffeine side effects including jitteriness, headache, and fast heartbeat.

Clozapine (Clozaril)

Interaction Rating=Moderate Be cautious with this combination.

The body breaks down clozapine to get rid of it. The caffeine in Ilex guayusa might decrease how fast the body breaks down clozapine. Taking Ilex guayusa along with clozapine can increase the effects and side effects of clozapine.

Dipyridamole (Persantine)

Interaction Rating=Moderate Be cautious with this combination.

The caffeine in Ilex guayusa might block the effects of dipyridamole. Dipyridamole is often used by doctors to do a test on the heart called a cardiac stress test. Stop taking Ilex guayusa or other caffeine-containing products at least 24 hours before a cardiac stress test.

Disulfiram (Antabuse)

Interaction Rating=Moderate Be cautious with this combination.

The body breaks down the caffeine in Ilex guayusa to get rid of it. Disulfiram can decrease how quickly the body gets rid of caffeine. Taking Ilex guayusa along with disulfiram might increase the risk of caffeine side effects, including jitteriness, irritability, and fast heartbeat.

Ephedrine

Interaction Rating=Major Do not take this combination.

Stimulant drugs speed up the nervous system. Caffeine, which is found in Ilex guayusa, and ephedrine are both stimulant drugs. Taking Ilex guayusa and ephedrine might cause too much stimulation and sometimes serious side effects and heart problems. Do not take caffeine-containing products and ephedrine at the same time.

Estrogens

Interaction Rating=Moderate Be cautious with this combination.

The body breaks down caffeine to get rid of it. Estrogens can decrease how quickly the body breaks down caffeine. Taking estrogen along with Ilex guayusa can increase the risk of side effects such as jitteriness, headache, and fast heartbeat.

Fluconazole (Diflucan)

Interaction Rating=Minor Be watchful with this combination.

The body breaks down the caffeine in Ilex guayusa to get rid of it. Fluconazole might decrease how quickly the body gets rid of caffeine. Taking fluconazole and Ilex guayusa might increase the risk of caffeine side effects, including jitteriness and fast heartbeat.

Flutamide (Eulexin)

Interaction Rating=Moderate Be cautious with this combination.

The body breaks down flutamide to get rid of it. Caffeine in Ilex guayusa might decrease how quickly the body breaks down flutamide. Taking Ilex guayusa along with flutamide might increase the effects and side effects of flutamide.

Fluvoxamine (Luvox)

Interaction Rating=Moderate Be cautious with this combination.

The body breaks down the caffeine in Ilex guayusa to get rid of it. Fluvoxamine can decrease how quickly the body breaks down caffeine. Taking caffeine along with fluvoxamine might increase the risk of caffeine side effects.

Lithium

Interaction Rating=Moderate Be cautious with this combination.

The body naturally gets rid of lithium. The caffeine in Ilex guayusa can increase how quickly the body gets rid of lithium. If you take products that contain caffeine and you take lithium, don't change your dose of caffeine quickly. Stopping caffeine too quickly can increase the side effects of lithium. If you stop using caffeine, reduce the dose slowly.

Medications for asthma (Beta-adrenergic agonists)

Interaction Rating=Moderate Be cautious with this combination.

Ilex guayusa contains caffeine. Caffeine can stimulate the heart. Some medications for asthma can also stimulate the heart. Taking caffeine with some medications for asthma might cause too much stimulation and cause heart problems.

Medications for depression (MAOIs)

Interaction Rating=Moderate Be cautious with this combination.

Ilex guayusa contains caffeine. There is some concern that caffeine can interact with certain medications, called MAOIs. If caffeine is taken with these medications, it might increase the risk for serious side effects including fast heartbeat and very high blood pressure.

Some common MAOIs include phenelzine (Nardil), selegiline (Zelapar), and tranylcypromine (Parnate).

Medications for diabetes (Antidiabetes drugs)

Interaction Rating=Minor Be watchful with this combination.

Ilex guayusa might lower blood sugar levels. Taking Ilex guayusa along with diabetes medications might cause blood sugar to drop too low. Monitor your blood sugar closely.

Medications that slow blood clotting (Anticoagulant / Antiplatelet drugs)

Interaction Rating=Moderate Be cautious with this combination.

Ilex guayusa might slow blood clotting. Taking Ilex guayusa along with medications that also slow blood clotting might increase the risk of bruising and bleeding.

Metformin (Glucophage)

Interaction Rating=Minor Be watchful with this combination.

Ilex guayusa contains caffeine. The body breaks down caffeine to get rid of it. Metformin can decrease how quickly the body breaks down caffeine. Taking metformin along with Ilex guayusa might increase the risk of caffeine side effects. such as jitteriness, headache, and fast heartbeat.

Methoxsalen (Oxsoralen)

Interaction Rating=Minor Be watchful with this combination.

Ilex guayusa contains caffeine. The body breaks down caffeine to get rid of it. Methoxsalen can decrease how quickly the body breaks down caffeine. Taking methoxsalen along with Ilex guayusa might increase the risk of caffeine side effects, such as jitteriness, headache, and fast heartbeat.

Mexiletine (Mexitil)

Interaction Rating=Minor Be watchful with this combination.

Ilex guayusa contains caffeine. The body breaks down caffeine to get rid of it. Mexiletine can decrease how quickly the body breaks down caffeine. Taking mexiletine along with Ilex guayusa might increase the risk of caffeine side effects, such as jitteriness, headache, and fast heartbeat.

Nicotine

Interaction Rating=Moderate Be cautious with this combination.

Ilex guayusa contains caffeine. Taking coffee along with nicotine might cause a fast heartbeat and increase blood pressure.

Pentobarbital (Nembutal)

Interaction Rating=Moderate Be cautious with this combination.

Ilex guayusa contains caffeine. The stimulant effects of caffeine can block the sleep-producing effects of pentobarbital.

Phenobarbital (Luminal)

Interaction Rating=Moderate Be cautious with this combination.

Phenobarbital is used to treat seizures. Caffeine, in Ilex guayusa might reduce the effects of phenobarbital. Taking Ilex guayusa with phenobarbital might reduce its effects and increase the risk of seizures.

Phenothiazines

Interaction Rating=Minor Be watchful with this combination.

Ilex guayusa contains caffeine. The body breaks down caffeine to get rid of it. Phenothiazines can decrease how quickly the body breaks down caffeine. Taking phenothiazines along with Ilex guayusa might increase the risk of caffeine side effects, such as jitteriness, headache, and fast heartbeat.

Phenylpropanolamine

Interaction Rating=Moderate Be cautious with this combination.

The caffeine in Ilex guayusa can stimulate the body. Phenylpropanolamine can also stimulate the body. Taking Ilex guayusa along with phenylpropanolamine might cause too much stimulation and increase heartbeat, blood pressure, and cause nervousness.

Phenytoin (Dilantin)

Interaction Rating=Moderate Be cautious with this combination.

Phenytoin is used to control some types of seizures. Caffeine in Ilex guayusa might reduce the effects of phenytoin. Taking Ilex guayusa with phenytoin might reduce its effects and increase the risk of seizures.

Pioglitazone (Actos)

Interaction Rating=Moderate Be cautious with this combination.

The caffeine in Ilex guayusa might increase the amount of pioglitazone that the body absorbs. Taking Ilex guayusa might increase the effects and adverse effects of pioglitazone.

Riluzole (Rilutek)

Interaction Rating=Moderate Be cautious with this combination.

The body breaks down riluzole to get rid of it. Taking Ilex guayusa can decrease how fast the body breaks down riluzole and increase the effects and side effects of riluzole.

Stimulant drugs

Interaction Rating=Moderate Be cautious with this combination.

Stimulants, such as amphetamines and cocaine, speed up the nervous system. By speeding up the nervous system, stimulant medications can increase blood pressure and speed up the heartbeat. Caffeine in Ilex guayusa can also speed up the nervous system. Taking Ilex guayusa along with stimulant drugs might cause serious problems including increased heart rate and high blood pressure.

Terbinafine (Lamisil)

Interaction Rating=Minor Be watchful with this combination.

Ilex guayusa contains caffeine. The body breaks down caffeine to get rid of it. Terbinafine can decrease how fast the body gets rid of caffeine and increase the risk of caffeine side effects such as jitteriness, headache, and fast heartbeat.

Theophylline

Interaction Rating=Moderate Be cautious with this combination.

Ilex guayusa contains caffeine. Caffeine works similarly to theophylline. Caffeine can also decrease how quickly the body gets rid of theophylline. Taking Ilex guayusa along with theophylline might increase the effects and side effects of theophylline.

Tiagabine (Gabitril)

Interaction Rating=Minor Be watchful with this combination.

Ilex guayusa contains caffeine. Tiagabine is used to treat seizures. There is some concern that caffeine can reduce the effects of tiagabine. But studies show that tiagabine still works even when taken with caffeine.

Ticlopidine (Ticlid)

Interaction Rating=Minor Be watchful with this combination.

Ilex guayusa contains caffeine. The body breaks down caffeine to get rid of it. Ticlopidine can decrease how fast the body gets rid of caffeine. Taking Ilex guayusa along with ticlopidine might increase the risk of caffeine side effects, such as jitteriness, headache, and fast heartbeat.

Valproate

Interaction Rating=Moderate Be cautious with this combination.

Valproate is used to treat seizures. Caffeine in Ilex guayusa might reduce the effects of valproate. Taking Ilex guayusa with valproate might reduce its effects and increase the risk of seizures.

Verapamil (Calan, others)

Interaction Rating=Moderate Be cautious with this combination.

The body breaks down the caffeine in Ilex guayusa to get rid of it. Verapamil can decrease how quickly the body gets rid of caffeine. Taking Ilex guayusa along with verapamil can increase the risk of caffeine side effects including jitteriness, headache, and fast heartbeat.

Water pills (Diuretic drugs)

Interaction Rating=Moderate Be cautious with this combination.

Ilex guayusa contains caffeine. Caffeine, especially in large amounts, can reduce potassium levels in the body. "Water pills" can also decrease potassium levels in the body. Taking large amounts of caffeine along with "water pills" might decrease potassium levels too much.

Interactions with herbs & supplements

Bitter orange: Ilex guayusa contains caffeine. Taking bitter orange along with herbs that contain caffeine, such as Ilex guayusa, can increase blood pressure and heart rate in people who otherwise have normal blood pressure. This might increase the chance of developing problems with the heart and blood vessels.
Caffeine-containing herbs and supplements: Ilex guayusa contains caffeine. Taking it along with other supplements that contain caffeine might increase caffeine side effects. Examples of supplements that contain caffeine include black tea, coffee, green tea, and yerba mate.
Calcium: High caffeine intake from foods, beverages, and herbs including Ilex guayusa increases how much calcium the body loses in the urine. This might lower calcium levels.
Cordyceps: Ilex guayusa contains caffeine. Cordyceps might increase how quickly the body gets rid of caffeine. This might decrease the effects of caffeine.
Danshen: Ilex guayusa contains caffeine. The body breaks down caffeine to get rid of it. Danshen might decrease how quickly the body breaks down caffeine. Using danshen with Ilex guayusa might increase the risk of caffeine side effects.
Echinachea: Ilex guayusa contains caffeine. The body breaks down caffeine to get rid of it. Echinacea might decrease how quickly the body breaks down caffeine. Using echinacea with Ilex guayusa might increase the risk of caffeine side effects.
Ephedra: Ilex guayusa contains caffeine. Using ephedra with caffeine might increase the risk of serious life-threatening or disabling conditions such as hypertension, heart attack, stroke, seizures, and death. Avoid this combination.
Herbs and supplements that might lower blood sugar: Ilex guayusa might lower blood sugar. Taking it with other supplements with similar effects might lower blood sugar too much. Examples of supplements with this effect include aloe, bitter melon, cassia cinnamon, chromium, and prickly pear cactus.
Herbs and supplements that might slow blood clotting: Ilex guayusa might slow blood clotting and increase the risk of bleeding. Taking it with other supplements with similar effects might increase the risk of bleeding in some people. Examples of supplements with this effect include garlic, ginger, ginkgo, nattokinase, and Panax ginseng.
Kudzu: Ilex guayusa contains caffeine. Kudzu seems to decrease how quickly the body breaks down caffeine. Using kudzu with caffeine might increase the risk of caffeine side effects.
Magnesium: High caffeine intake from foods, beverages, and herbs including Ilex guayusa increases how much magnesium the body loses in the urine. This might lower magnesium levels.
Melatonin: Ilex guayusa contains caffeine. Taking caffeine along with melatonin can increase melatonin levels. Taking Ilex guayusa with melatonin might increase melatonin effects and side effects.

Interactions with foods

There are no known interactions with foods.