The P-I-E-N-O Parkinsn's List Drug Database
caffeine / NodozTM , VivarinTM
STIMULANT:
Description: Caffeine is a naturally occurring xanthine derivative. Other xanthine derivatives include the bronchodilator theophylline and theobromine, a compound found in cocoa and chocolate. Caffeine is found in many beverages and soft drinks. Clinically, it is used parenterally as a respiratory stimulant in neonates. It also is sold without a prescription in products marketed to treat drowsiness. Caffeine was first approved by the FDA for use in a drug product in 1938.
Mechanism of Action: Caffeine is a mild, direct stimulant at all levels of the CNS and also stimulates the heart and cardiovascular system. The related xanthine, theophylline, shares these properties and is widely used in the treatment of pulmonary disease. Both caffeine and theophylline are CNS stimulants, with theophylline exerting more dramatic effects than caffeine at higher concentrations. Caffeine also stimulates the medullary respiratory center and relaxes bronchial smooth muscle. Caffeine stimulates voluntary muscle and gastric acid secretion, increases renal blood flow, and is a mild diuretic.
While the clinical responses to caffeine are well known, the cellular mechanism of action is uncertain. Several theories have been proposed. At high concentrations, caffeine interferes with the uptake and storage of calcium by sarcoplasmic reticulum of striated muscle. While this action would explain the effects of caffeine on cardiac and skeletal muscle, it does not appear to occur at clinically achievable concentrations. Inhibition of phosphodiesterases (and subsequent accumulation of cyclic nucleotides) also does not appear to occur at clinically achievable concentrations.
Currently, it is believed that xanthines act as adenosine-receptor antagonists. Adenosine acts as an autocoid, and virtually every cell contains adenosine receptors within the plasma membrane. Adenosine exerts complex actions. It inhibits the release of neurotransmitters from presynaptic sites but works in concert with norepinephrine or angiotensin to augment their actions. Antagonism of adenosine receptors by caffeine would appear to promote neurotransmitter release, thus explaining the stimulatory effects of caffeine. Recently, a distinct syndrome has been associated with caffeine withdrawal. It is possible that the manifestations of caffeine withdrawal may be secondary to catecholamine or neurotransmitter depletion.
Pharmacokinetics: Caffeine and citrated caffeine are well absorbed from the GI tract. Absorption from suppositories may be slow and erratic. Following oral administration, peak plasma concentrations are reached within 50-75 minutes. Caffeine is distributed rapidly to all body tissues and readily crosses the blood-brain and placental barriers. It is distributed into breast milk. About 17% is bound to plasma proteins. The drug is partially metabolized in the liver, and unchanged drug and metabolites are excreted in the urine. Plasma half-life is 3-4 hours in adults but about 80 hours in neonates who had absorbed caffeine from their mothers.
CONTRAINDICATIONS/PRECAUTIONS: Caffeine should be used cautiously in patients with anxiety disorders and/or panic disorder because it can aggravate these conditions. Caffeine should not be consumed by patients suffering from insomnia, nor should it be consumed prior to retiring because it can cause insomnia.
Caffeine is relatively contraindicated in patients with cardiac disease. Caffeine can stimulate the force of contraction and can increase heart rate. Patients who have angina or a history of cardiac arrhythmias should not receive or should minimize their intake of caffeine.
Caffeine should be used cautiously in patients with hepatic disease or hepatic impairment. Caffeine clearance may be delayed, leading to toxicity.
Patients with hypertension should not receive or should minimize their intake of caffeine.
Patients with diabetes mellitus should not receive or should minimize their intake of caffeine. Although the effects are mild, caffeine can raise blood sugar.
Patients with thyroid disease, especially hyperthyroidism, should not receive or should minimize their intake of caffeine. The stimulatory effects of caffeine can be augmented in hyperthyroidism.
Caffeine can stimulate gastric secretions. Patients with peptic ulcer disease should not receive or should minimize their intake of caffeine because the condition can be aggravated.
Caffeine should be used cautiously, if at all, during pregnancy and during breast-feeding. Although only small amounts are secreted in milk, caffeine can accumulate in the neonate. Fetal arrhythmias have been reported when caffeine was consumed during pregnancy.
DRUG INTERACTIONS: The CNS-stimulating actions of caffeine can be additive with other CNS stimulants or psychostimulants. Caffeine should be avoided or used cautiously with dextroamphetamine, methylphenidate, nicotine, pemoline, pseudoephedrine, phenylpropanolamine, or œA-agonists or other sympathomimetics. When combined with any of these medications, caffeine can cause nervousness, irritability, insomnia, and/or cardiac arrhythmias. The combination of caffeine and phenylpropranolamine has been associated with cerebrovascular accidents, so these agents should not be used together.
A single case report associates the appearance of psychiatric symptoms with caffeine ingestion in a patient taking clozapine. Although clozapine could have inhibited caffeine metabolism and these symptoms could be a result of caffeine excess, it is also possible that caffeine inhibited the therapeutic action of clozapine. Until more data are available, caffeine consumption should be minimized in patients requiring clozapine.
Caffeine interacts with MAOIs (including furazolidone, procarbazine, and selegiline). Dangerous cardiac arrhythmias or severe hypertension can occur because of the potentiation of caffeine's sympathomimetic effects by MAOIs. Caffeine use should be minimized or avoided during and for 1-2 weeks after discontinuation of any MAOI.
ADVERSE REACTIONS: Caffeine is a CNS stimulant. Many adverse reactions to caffeine are an extension of caffeine's pharmacologic actions. At therapeutic or nontoxic doses, caffeine can cause tremor, sinus tachycardia, and heightened attentiveness. Other adverse reactions include diarrhea, excitement, palpitations, insomnia, headache, and muscle twitches. After excessive doses, caffeine can cause considerable nausea/vomiting and anxiety. Cardiac arrhythmias, seizures, and delirium are possible after deliberate overdoses.
Caffeine is a mild diuretic. Polyuria can occur.
In 1992, a distinct caffeine withdrawal syndrome was described. Patients who consume or receive caffeine daily for several weeks experience notable physical and psychiatric responses including lethargy, anxiety, dizziness, or headache.
PATIENT INFORMATION:
What do caffeine tablets do?
Caffeine (NoDozTM , VivarinTM ) acts as a central nervous system (CNS) or brain stimulant, increasing alertness in people who are tired or sleepy. Caffeine occurs naturally in tea, coffee, cocoa, and chocolate, and is added to many soft drinks. Generic forms of caffeine are available, and can be obtained without a prescription.
What should my doctor or pharmacist know before I take caffeine?
They need to know if you have any of these conditions:
How should I take this medicine? Take caffeine tablets or caplets by mouth. Follow the directions on the prescription label. Swallow with a drink of water; do not take with grapefruit juice. If you are taking an extended- release form of caffeine, swallow whole, do not crush or chew. If you are taking chewable tablets, chew well and swallow. Do not take your medicine more often than directed. Do not stop taking except on your doctor's advice.
Special precautions for use in children:
This medicine is not for children under 12 years old.
What if I miss a dose?
If you miss a dose, take it as soon as you can. If it is almost time for your next dose, take only that dose. Do not take double or extra doses.
What other medicines can interact with caffeine?
Tell your doctor or pharmacist: about all other medicines you are taking, including non-prescription medicines; if you are a frequent user of drinks with caffeine or alcohol; if you smoke; or if you use illegal drugs. These may affect the way your medicine works. Check before stopping or starting any of your medicines.
What side effects may I notice from taking caffeine?
Serious side effects with caffeine include:
Stop using caffeine and call your doctor as soon as you can if you get any of these side effects.
Minor side effects with caffeine include:
Reduce your intake of caffeine if you get any of these side effects. Let your doctor know about them if they do not go away or if they annoy you.
What do I need to watch for while I take caffeine?
Caffeine is not intended for long-term use. Do not use caffeine products regularly to make up for lost sleep. Do not increase the dose if tolerance develops; your body will not develop a tolerance to the harmful side effects of caffeine. See your doctor if you continue to experience tiredness or constant sleepiness; this may indicate a problem needing medical attention.
Do not take caffeine close to bedtime. It may prevent you from sleeping.
If you have been a regular caffeine user you can get withdrawal symptoms if you stop taking caffeine. Symptoms include tiredness, dizziness, headache, anxiety, or nervousness. This can be a weekend effect for people who drink a lot of coffee during their working week.
If you are taking caffeine as a part of a medical treatment, avoid food and drinks that contain additional caffeine.
Do not take caffeine with other non-prescription medicines, especially cold and allergy medicines, without asking your doctor or pharmacist for advice. Do not take caffeine with grapefruit juice, this can increase the effects of caffeine.
Where can I keep my medicine?
Keep out of the reach of children in a container that small children cannot open.
Store at room temperature between 15 and 30 C (59 and 86F). Throw away any unused medicine after the expiration date.
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