Coffee is a drink made from coffee beans, which are the roasted fruit of the Coffea arabica bush.
People most commonly drink coffee to relieve mental and physical fatigue and to increase mental alertness. Coffee is also used to prevent Parkinson disease, dementia, and many other conditions, but there is no good scientific evidence to support many of these uses.
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Coffee contains caffeine. Caffeine works by stimulating the central nervous system (CNS), heart, and muscles. Coffee also contains other chemicals that might have other benefits.
When taken by mouth: Coffee is LIKELY SAFE for most healthy adults when consumed in moderate amounts (about 4 cups per day). Coffee containing caffeine can cause insomnia, nervousness and restlessness, stomach upset, nausea and vomiting, increased heart and breathing rate, and other side effects.
Caffeinated coffee is POSSIBLY UNSAFE when taken by mouth for a long time or in high doses (more than 4 cups per day). Drinking large amounts of caffeinated coffee might cause headache, anxiety, agitation, ringing in the ears, and irregular heartbeats. Larger doses might cause headache, anxiety, agitation, and chest pain.
When given as an enema (rectally): Coffee is POSSIBLY UNSAFE when given rectally as an enema. Coffee enemas have been linked to cases of severe side effects, including death.
Special Precautions & Warnings:
Pregnancy and breast-feeding: Caffeinated coffee is POSSIBLY SAFE for pregnant women in amounts of 3 cups per day or less. This amount of coffee provides about 300 mg of caffeine. Consuming larger amounts during pregnancy or when breast-feeding is POSSIBLY UNSAFE. Drinking more than 3 cups per day during pregnancy has been linked to an increased risk of miscarriage, premature birth, and low birth weight. These risks increase as the amount of coffee the mother drinks during pregnancy increases. Also, caffeine can pass into breast milk, so nursing mothers should closely monitor caffeine intake to make sure it is on the low side (1-2 cups per day). High intake of caffeine by nursing mothers can cause sleep problems, irritability, and increased bowel activity in breast-fed infants.Children: Caffeinated coffee is POSSIBLY SAFE when taken by children and adolescents in amounts commonly found in foods and beverages.
Anxiety disorders: The caffeine in coffee might make anxiety worse.
Bipolar disorder: The caffeine in coffee might make symptoms of mania worse.
Bleeding disorders: There is some concern that coffee might make bleeding disorders worse.
Heart disease: Most research in people with heart disease shows that drinking coffee on a daily basis does not increase the risk for serious complications. However, people who smoke and have heart disease might have an increased risk of dying from heart disease if they consume coffee daily.
Diabetes: Some research suggests that caffeine contained in coffee might change the way people with diabetes process sugar. Caffeine has been reported to cause increases as well as decreases in blood sugar. Use caffeine with caution if you have diabetes and monitor your blood sugar carefully.
Diarrhea: Coffee contains caffeine. The caffeine in coffee, especially when taken in large amounts, can worsen diarrhea.
Epilepsy: Coffee contains caffeine. People with epilepsy should avoid using caffeine in high doses. Low doses of caffeine should be used cautiously.
Glaucoma: Drinking caffeinated coffee increases pressure inside the eye. The increase starts within 30 minutes and lasts for at least 90 minutes.
High blood pressure: Drinking caffeinated coffee might increase blood pressure in people with high blood pressure. However, this effect might be less in people who drink coffee regularly.
Irritable bowel syndrome (IBS): Coffee contains caffeine. The caffeine in coffee, especially when taken in large amounts, may worsen diarrhea and other symptoms of IBS.
Loss of bladder control: Coffee contains caffeine. Caffeine can make bladder control worse by increasing frequency of urination and the urge to urinate.
Osteoarthritis: Drinking 7 cups or more of coffee per day has been linked to a greater chance of knee osteoarthritis in Korean men, but not women.
Smoking: People who smoke and drink more coffee might have an increased risk of dying from heart disease or cancer.
Thinning bones (osteoporosis): Drinking caffeinated coffee can increase the amount of calcium that is flushed out in the urine. This might weaken bones. If you have osteoporosis, limit caffeine consumption to less than 300 mg per day (less than 3 cups of caffeinated coffee). Taking calcium supplements may help to make up for calcium that is lost. If you are generally healthy and getting enough calcium from your food and supplements, taking up to 400 mg of caffeine daily (about 4 cups of coffee) doesn't seem to increase the risk of getting osteoporosis. Postmenopausal women who have an inherited condition that keeps them from processing vitamin D normally, should be especially cautious when using caffeine.
Adenosine (Adenocard)
Interaction Rating=Moderate Be cautious with this combination.
The caffeine in coffee might block the affects of adenosine (Adenocard). Adenosine (Adenocard) is often used by doctors to do a test on the heart. This test is called a cardiac stress test. Stop consuming coffee or other caffeine-containing products at least 24 hours before a cardiac stress test.
Alcohol
Interaction Rating=Moderate Be cautious with this combination.
The body breaks down the caffeine in coffee to get rid of it. Alcohol can decrease how quickly the body breaks down caffeine. Taking coffee along with alcohol might cause too much caffeine in the bloodstream and caffeine side effects including jitteriness, headache, and fast heartbeat.
Alendronate (Fosamax)
Interaction Rating=Moderate Be cautious with this combination.
Coffee can decrease how much alendronate (Fosamax) the body absorbs. Taking coffee and alendronate (Fosamax) at the same time can decrease the effectiveness of alendronate (Fosamax). Don't drink coffee within two hours of taking alendronate (Fosamax).
Antibiotics (Quinolone antibiotics)
Interaction Rating=Moderate Be cautious with this combination.
The body breaks down caffeine to get rid of it. Some antibiotics might decrease how quickly the body breaks down caffeine. Taking these antibiotics along with coffee can increase the risk of side effects including jitteriness, headache, increased heart rate, and other side effects.
Some antibiotics that decrease how quickly the body breaks down caffeine include ciprofloxacin (Cipro), enoxacin (Penetrex), norfloxacin (Chibroxin, Noroxin), sparfloxacin (Zagam), trovafloxacin (Trovan), and grepafloxacin (Raxar).
Birth control pills (Contraceptive drugs)
Interaction Rating=Minor Be watchful with this combination.
The body breaks down the caffeine in coffee to get rid of it. Birth control pills can decrease how quickly the body breaks down caffeine. Taking coffee along with birth control pills can cause jitteriness, headache, fast heartbeat, and other side effects.
Some birth control pills include ethinyl estradiol and levonorgestrel (Triphasil), ethinyl estradiol and norethindrone (Ortho-Novum 1/35, Ortho-Novum 7/7/7), and others.
Cimetidine (Tagamet)
Interaction Rating=Minor Be watchful with this combination.
The body breaks down the caffeine in coffee to get rid of it. Cimetidine (Tagamet) can decrease how quickly your body breaks down caffeine. Taking cimetidine (Tagamet) along with coffee might increase the chance of caffeine side effects including jitteriness, headache, fast heartbeat, and others.
Clozapine (Clozaril)
Interaction Rating=Moderate Be cautious with this combination.
The body breaks down clozapine (Clozaril) to get rid of it. The caffeine in coffee might decrease how fast the body breaks down clozapine (Clozaril). Taking coffee along with clozapine (Clozaril) can increase the effects and side effects of clozapine (Clozaril).
Dipyridamole (Persantine)
Interaction Rating=Moderate Be cautious with this combination.
The caffeine in coffee might block the affects of dipyridamole (Persantine). Dipyridamole (Persantine) is often used by doctors to do a test on the heart. This test is called a cardiac stress test. Stop drinking coffee 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 coffee to get rid of it. Disulfiram (Antabuse) can decrease how quickly the body gets rid of caffeine. Taking coffee along with disulfiram (Antabuse) might increase the effects and side effects of coffee including jitteriness, hyperactivity, irritability, and others.
Ephedrine
Interaction Rating=Major Do not take this combination.
Stimulant drugs speed up the nervous system. The caffeine in coffee and ephedrine are both stimulant drugs. Drinking coffee and taking 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 the caffeine in coffee to get rid of it. Estrogens can decrease how quickly the body breaks down caffeine. Taking estrogen pills and drinking coffee can cause jitteriness, headache, fast heartbeat, and other side effects. If you take estrogen pills limit your caffeine intake.
Some estrogen pills include conjugated equine estrogens (Premarin), ethinyl estradiol, estradiol, and others.
Fluconazole (Diflucan)
Interaction Rating=Minor Be watchful with this combination.
The body breaks down the caffeine in coffee to get rid of it. Fluconazole (Diflucan) might decrease how quickly the body gets rid of caffeine. Taking fluconazole (Diflucan) and drinking coffee might increase the effects and side effects of coffee including nervousness, anxiety, and insomnia.
Fluvoxamine (Luvox)
Interaction Rating=Moderate Be cautious with this combination.
The body breaks down the caffeine in coffee to get rid of it. Fluvoxamine (Luvox) can decrease how quickly the body breaks down caffeine. Taking caffeine along with fluvoxamine (Luvox) might cause too much caffeine in the body, and increase the effects and side effects of caffeine.
Levothyroxine (Synthroid, Levothroid, Levoxyl, and others)
Interaction Rating=Moderate Be cautious with this combination.
Drinking some types of coffee might reduce the amount of levothyroxine that is absorbed when taken by mouth. This can decrease how well levothyroxine works. Avoid drinking coffee at the same time that you take levothyroxine and for an hour afterwards.
Lithium
Interaction Rating=Moderate Be cautious with this combination.
You body naturally gets rid of lithium. The caffeine in coffee can increase how quickly your body gets rid of lithium. If you take products that contain caffeine and you take lithium, stop taking caffeine products slowly. Stopping caffeine too quickly can increase the side effects of lithium.
Medications for depression (MAOIs)
Interaction Rating=Moderate Be cautious with this combination.
The caffeine in coffee can stimulate the body. Some medications used for depression can also stimulate the body. Drinking coffee and taking some medications for depression might cause too much stimulation and serious side effects including fast heartbeat, high blood pressure, nervousness, and others.
Some of these medications used for depression include phenelzine (Nardil), tranylcypromine (Parnate), and others.
Medications for depression (Tricyclic Antidepressants)
Interaction Rating=Moderate Be cautious with this combination.
Coffee contains chemicals called tannins. Tannins can bind to many medications and decrease how much medicine the body absorbs. To avoid this interaction avoid coffee one hour before and two hours after taking medications for depression called tricyclic antidepressants.
Some medications for depression include amitriptyline (Elavil) or imipramine (Tofranil, Janimine).
Medications for diabetes (Antidiabetes drugs)
Interaction Rating=Minor Be watchful with this combination.
Coffee might increase blood sugar. Diabetes medications are used to lower blood sugar. By increasing blood sugar, coffee might decrease the effectiveness of diabetes medications. Monitor your blood sugar closely. The dose of your diabetes medication might need to be changed.
Some medications used for diabetes include glimepiride (Amaryl), glyburide (DiaBeta, Glynase PresTab, Micronase), insulin, pioglitazone (Actos), rosiglitazone (Avandia), chlorpropamide (Diabinese), glipizide (Glucotrol), tolbutamide (Orinase), and others.
Medications that slow blood clotting (Anticoagulant / Antiplatelet drugs)
Interaction Rating=Moderate Be cautious with this combination.
Coffee might slow blood clotting. Taking coffee along with medications that also slow clotting might increase the chances of bruising and bleeding.
Some medications that slow blood clotting include aspirin, clopidogrel (Plavix), diclofenac (Voltaren, Cataflam, others), ibuprofen (Advil, Motrin, others), naproxen (Anaprox, Naprosyn, others), dalteparin (Fragmin), enoxaparin (Lovenox), heparin, warfarin (Coumadin), and others.
Mexiletine (Mexitil)
Interaction Rating=Minor Be watchful with this combination.
Coffee contains caffeine. The body breaks down caffeine to get rid of it. Mexiletine (Mexitil) can decrease how quickly the body breaks down caffeine. Taking Mexiletine (Mexitil) along with coffee might increase the caffeine effects and side effects of coffee.
Pentobarbital (Nembutal)
Interaction Rating=Moderate Be cautious with this combination.
The stimulant effects of the caffeine in coffee can block the sleep-producing effects of pentobarbital.
Phenothiazines
Interaction Rating=Moderate Be cautious with this combination.
Coffee contains chemicals called tannins. Tannins can bind to many medications and decrease how much medicine the body absorbs. To avoid this interaction avoid coffee one hour before and two hours after taking phenothiazine medications.
Some phenothiazine medications include fluphenazine (Permitil, Prolixin), chlorpromazine (Thorazine), haloperidol (Haldol), prochlorperazine (Compazine), thioridazine (Mellaril), and trifluoperazine (Stelazine).
Phenylpropanolamine
Interaction Rating=Moderate Be cautious with this combination.
The caffeine in coffee can stimulate the body. Phenylpropanolamine can also stimulate the body. Taking caffeine and phenylpropanolamine together might cause too much stimulation and increase heartbeat, blood pressure, and cause nervousness.
Riluzole (Rilutek)
Interaction Rating=Moderate Be cautious with this combination.
The body breaks down riluzole (Rilutek) to get rid of it. Drinking coffee can decrease how fast the body breaks down riluzole (Rilutek) and increase the effects and side effects of riluzole.
Stimulant drugs
Interaction Rating=Moderate Be cautious with this combination.
Stimulant drugs speed up the nervous system. By speeding up the nervous system, stimulant medications can make you feel jittery and speed up your heartbeat. The caffeine in coffee can also speed up the nervous system. Drinking coffee along with stimulant drugs might cause serious problems including increased heart rate and high blood pressure. Avoid taking stimulant drugs along with coffee.
Some stimulant drugs include diethylpropion (Tenuate), epinephrine, phentermine (Ionamin), pseudoephedrine (Sudafed), and many others.
Terbinafine (Lamisil)
Interaction Rating=Minor Be watchful with this combination.
The body breaks down the caffeine in coffee to get rid of it. Terbinafine (Lamisil) can decrease how fast the body gets rid of caffeine and increase the risk of side effects including jitteriness, headache, increased heartbeat, and other effects.
Theophylline
Interaction Rating=Moderate Be cautious with this combination.
The caffeine in coffee works similarly to theophylline. Caffeine can also decrease how quickly the body gets rid of theophylline. Drinking coffee and taking theophylline might increase the effects and side effects of theophylline.
Verapamil (Calan, Covera, Isoptin, Verelan)
Interaction Rating=Moderate Be cautious with this combination.
The body breaks down the caffeine in coffee to get rid of it. Verapamil (Calan, Covera, Isoptin, Verelan) can decrease how quickly the body gets rid of caffeine. Drinking coffee and taking verapamil (Calan, Covera, Isoptin, Verelan) can increase the risk of side effects for coffee including jitteriness, headache, and an increased heartbeat.
Bitter orange: Bitter orange in combination with caffeine or caffeine-containing herbs can increase blood pressure and heart rate in otherwise healthy adults with normal blood pressure. This might increase the risk of developing serious heart problems. Avoid this combination.
Caffeine-containing herbs and supplements: Using coffee along with other caffeine-containing herbs and supplements increases exposure to caffeine and increases the risk of developing caffeine-related side effects. Other natural products that contain caffeine include black tea, cocoa, cola nut, green tea, oolong tea, guarana, and mate.
Calcium: High caffeine intake from foods and beverages including coffee increases the amount of calcium that is flushed out in the urine.
Creatine: There is some concern that combining caffeine or caffeine-containing beverages and herbs with ephedra and creatine might increase the risk of serious side effects. There is a report of stroke in one athlete who used creatine monohydrate, caffeine, ephedra, and a variety of other supplements daily for 6 weeks. Caffeine might also decrease creatine's possible beneficial effects on athletic performance.
Echinacea: The body breaks down caffeine to get rid of it. Echinacea might decrease how quickly the body breaks down caffeine. Using echinacea with caffeine might increase caffeine levels.
Ephedra (Ma huang): Coffee contains caffeine, which is a stimulant. Using coffee with ephedra, which is also a stimulant, might increase the risk of experiencing serious or life-threatening side effects such as high blood pressure, heart attack, stroke, seizures, and death. Avoid taking coffee with ephedra and other stimulants.
Genistein-containing herbs and supplements: The body breaks down caffeine to get rid of it. Taking herbs or supplements that contain genistein might decrease how quickly the body breaks down caffeine. Using genistein with caffeine might increase caffeine levels.
Herbs and supplements that slow blood clotting: The caffeine in coffee might slow blood clotting. Drinking coffee and using herbs that might also slow blood clotting could increase the risk of bleeding in some people. Some of these herbs include angelica, clove, danshen, garlic, ginger, ginkgo, Panax ginseng, and others.
Kudzu: The body breaks down caffeine to get rid of it. Kudzu seems to decrease how quickly the body breaks down caffeine. Using kudzu with caffeine might increase caffeine levels.
Magnesium: Drinking large amounts of coffee might lower magnesium levels by a small amount.
Melatonin: Drinking coffee that contains caffeine at the same time as taking melatonin can increase melatonin levels.
There are no known interactions with foods.
The following doses have been studied in scientific research:
BY MOUTH:
- For headache or improving mental alertness: The typical dose of caffeine is up to 250 mg per day, which is about 2 cups of coffee. Even a single cup of coffee with caffeine can be used.
- For Parkinson disease: 3-4 cups of caffeinated coffee per day or 421 mg to 2716 mg total caffeine. However, a significantly lower risk of developing Parkinson disease has also been associated with as little as 124 mg to 208 mg of caffeine (approximately one to two cups of coffee).
- For death from any cause: At least one cup of ground, instant, or decaffeinated coffee per day has been used long-term.
- For diabetes: 900 mg caffeine per day (six or more cups of coffee per day) long-term.
- Impaired movement of food through the intestines after surgery: 100 mL of coffee three times a day starting after surgery and continuing until the first bowel movement has been used.
Brewed coffee contains around 100-150 mg caffeine per cup. Instant coffee contains 85-100 mg caffeine per cup. Decaffeinated coffee contains approximately 8 mg caffeine per cup. Darker roasts contain less caffeine due to the roasting process.
Cafe, Café, Café Arabica, Café Robusta, Caffea, Coffea arabica, Coffea arnoldiana, Coffea bukobensis, Coffea canephora, Coffea Cruda, Coffea liberica, Coffea robusta, Espresso, Expresso, Java, Mocha.
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