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Caffeine, Oral

What are other names for this medicine?

Type of medicine: stimulant

Generic and brand names: caffeine, oral; Caffedrine Caplets; Coffee Break; Dexitac Stay Alert Stimulant; Enerjets; Keep Alert; NoDoz Maximum Strength Caplets; NoDoz; Pep-Back; Quick Pep; Snap Back; Stay Awake; Tirend; Ultra Pep-Back; Vivarin

What is this medicine used for?

This medicine is taken by mouth to increase alertness when you feel tired or drowsy. It is not recommended to replace normal sleep. It may also be used with pain relievers to treat headaches.

What should my health care provider know before I take this medicine?

Before taking this medicine, tell your health care provider if you have:

  • an allergy to any medicine
  • panic or anxiety disorder
  • diabetes
  • heart disease
  • high blood pressure
  • kidney or liver disease
  • peptic ulcer disease or colitis
  • seizures
  • thyroid disease
  • trouble sleeping.

Females of childbearing age: This medicine may cause miscarriage or may affect the way a baby develops. Do not take more than 300 mg (an amount equal to three cups of coffee) a day if you are pregnant or breast-feeding.

How should I take it?

Take caffeine early in the day to avoid trouble sleeping.

Take this medicine exactly as directed. Do not take more of it or take it longer than recommended. Taking too much caffeine may cause side effects or become habit-forming.

The capsules are usually extended-release. Do not open or chew the capsules. Swallow them whole.

What should I watch out for?

Call your health care provider if you feel drowsy for 2 weeks or longer.

Do not drink a lot of coffee, tea, or cola while you are taking this medicine. These drinks also contain caffeine, and the combination may overstimulate you and cause side effects. Also check the labels of all nonprescription and prescription medicines you take. Other medicines that contain caffeine may also cause problems. Ask your health care provider or pharmacist if you have any questions.

If you feel dizzy or have a fast heartbeat, stop taking the caffeine. If the dizziness or fast heartbeat continues, contact your health care provider.

What are the possible side effects?

Along with its needed effects, your medicine may cause some unwanted side effects. Some side effects may be very serious. Some side effects may go away as your body adjusts to the medicine. Tell your health care provider if you have any side effects that continue or get worse.

Serious (report these to your health care provider right away): Stomach pain, extreme agitation or irritability, confusion, muscle twitching, headache, vomiting, and ringing in your ears.

Other: Dizziness, fast heartbeat, diarrhea, nervousness, trouble sleeping, mild nausea, mild nervousness.

What products might interact with this medicine?

When you take this medicine with other medicines, it can change the way this or any of the other medicines work. Nonprescription medicines, vitamins, natural remedies, and certain foods may also interact. Using these products together might cause harmful side effects. Talk to your health care provider if you are taking:

  • amantadine (Symmetrel)
  • antibiotics such as ciprofloxacin (Cipro) and enoxacin (Penetrex)
  • antidepressants such as bupropion (Wellbutrin), fluoxetine (Prozac), paroxetine (Paxil), and sertraline (Zoloft)
  • antiseizure medicines such as phenytoin (Dilantin, Phenytek) and phenobarbital (Luminal)
  • appetite suppressants (diet pills)
  • cimetidine (Tagamet)
  • clozapine (Clozaril)
  • disulfiram (Antabuse)
  • drinks and foods containing caffeine such as coffee, tea, colas, and chocolate
  • female hormones such estrogen or birth control pills
  • herbs with stimulant effects such as ephedra, ma huang, guarana
  • medicines for colds, sinus problems, hay fever or other allergies that contain pseudoephedrine (including nose drops or sprays)
  • mexiletine (Mexitil, Novo-Mexiletine)
  • MAO inhibitors such as furazolidone (Furoxone), isocarboxazid (Marplan), phenelzine (Nardil), procarbazine (Matulane), selegiline (Eldepryl), and tranylcypromine (Parnate) (Do not take an MAO inhibitor and this medicine within 14 days of each other.)
  • other stimulant medicines such as amphetamines (Desoxyn, Dexedrine), dextroamphetamines (Adderall, Adderall XR), methylphenidate (Ritalin), and pemoline (Cylert)
  • terbinafine (Lamisil)
  • theophylline.

Do not eat grapefruit or drink grapefruit juice while taking this medicine. Grapefruit affects the way this medicine works and may increase the risk of side effects.

Keep a list of all your medicines (prescription, nonprescription, supplements, natural remedies, and vitamins) with you. Be sure that you tell all health care providers who treat you about all the products you are taking.

How should I store this medicine?

Store this medicine at room temperature. Keep the container tightly closed. Protect it from heat, high humidity, and bright light.


This advisory includes selected information only and may not include all side effects of this medicine or interactions with other medicines. Ask your health care provider or pharmacist for more information or if you have any questions.

Ask your pharmacist for the best way to dispose of outdated medicine or medicine you have not used. Do not throw medicine in the trash.

Keep all medicines out of the reach of children.

Do not share medicines with other people.

Developed by McKesson Provider Technologies.
Published by McKesson Provider Technologies.
Last modified: 2004-10-15
Last reviewed: 2004-10-06
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
Copyright © 2005 McKesson Corporation and/or one of its subsidiaries. All Rights Reserved.