Fioricet and Esgic is made from a combination of butalbital (a barbiturate, 50 mg), acetaminophen (325 mg), and caffeine (40 mg). They are indicated for the treatment of tension headaches and muscle contraction headaches. Although not indicated, they are commonly used to treat migraines and other pain related ailments. Note that Fioricet (and some other pain medications) are implicated as causing repeat headaches with over-use. Butalbital has generalized depressant effect on central nervous system and, in very high doses, has peripheral effects. Acetaminophen has analgesic and antipyretic effects; its analgesic effects may be mediated through inhibition of prostaglandin synthetase enzyme complex. Caffeine is thought to produce constriction of cerebral blood vessels. Butalbital has a half-life of about 35 hours. Acetaminophen has a half-life of about 1.25 to 3 hours, but may be increased by liver damage and after an overdose. Caffeine has a half-life of about 3 hours.
Fioricet Clinical Pharmacology
This combination drug product is intended as a treatment for tension headache. It consists of a fixed combination of butalbital, acetaminophen, and caffeine. The role each component plays in the relief of the complex of symptoms known as tension headache is incompletely understood.
Pharmacokinetics
The behavior of the individual components is described below.
Butalbital
Butalbital is well absorbed from the gastrointestinal tract and is expected to distribute to most tissues in the body. Barbiturates in general may appear in breast milk and readily cross the placental barrier. They are bound to plasma and tissue proteins to a varying degree and binding increases directly as a function of lipid solubility.
Elimination of butalbital is primarily via the kidney (59% to 88% of the dose) as unchanged drug or metabolites. The plasma half-life is about 35 hours. Urinary excretion products include parent drug (about 3.6% of the dose), 5-isobutyl-5-(2, 3-dihydroxypropyl) barbituric acid (about 24% of the dose), 5-allyl-5(3-hydroxy-2-methyl-1-propyl) barbituric acid (about 4.8% of the dose), products with the barbituric acid ring hydrolyzed with excretion of urea (about 14% of the dose), as well as unidentified materials. Of the material excreted in the urine, 32% is conjugated.
The in vitro plasma protein binding of butalbital is 45% over the concentration range of 0.5-20 mcg/mL. This falls within the range of plasma protein binding (20%-45%) reported with other barbiturates such as phenobarbital, pentobarbital, and secobarbital sodium. The plasma-to-blood concentration ratio was almost unity, indicating that there is no preferential distribution of butalbital into either plasma or blood cells.
Acetaminophen
Acetaminophen is rapidly absorbed from the gastrointestinal tract and is distributed throughout most body tissues. The plasma half-life is 1.25 to 3 hours, but may be increased by liver damage and following overdosage. Elimination of acetaminophen is principally by liver metabolism (conjugation) and subsequent renal excretion of metabolites. Approximately 85% of an oral dose appears in the urine within 24 hours of administration, most as the glucuronide conjugate, with small amounts of other conjugates and unchanged drug.
Caffeine
Like most xanthines, caffeine is rapidly absorbed and distributed in all body tissues and fluids, including the CNS, fetal tissues, and breast milk.
Caffeine is cleared through metabolism and excretion in the urine. The plasma half-life is about 3 hours. Hepatic biotransformation prior to excretion results in about equal amounts of 1-methylxanthine and 1-methyluric acid. Of the 70% of the dose that is recovered in the urine, only 3% is unchanged drug.
FIORICET SIDE EFFECTS:
Nausea, vomiting, abdominal pain, shaking (tremor), shortness of breath, lightheadedness, dizziness, or drowsiness may occur. If any of these effects persist or worsen, notify your doctor or pharmacist promptly.
To lower your risk of dizziness and lightheadedness, get up slowly when rising from a sitting or lying position.Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.Tell your doctor immediately if any of these unlikely but serious side effects occur: mental/mood changes, fainting, seizure, fast/irregular heartbeat, increased thirst/urination.Tell your doctor immediately if any of these rare but very serious side effects occur: signs of infection (e.g., fever, persistent sore throat), easy bruising/bleeding, change in the amount of urine.If you do not have liver problems, the adult maximum dose of acetaminophen is 4 grams per day (4000 milligrams). If you take more than the maximum daily amount, it may cause serious (possibly fatal) liver disease. Seek immediate medical attention if you have any of the following symptoms of liver damage: persistent nausea/vomiting, yellowing eyes/skin, dark urine, severe stomach/abdominal pain, extreme tiredness.If you have liver problems, consult your doctor or pharmacist for a safe dosage of this medication.A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.In Canada – Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
FIORICET PRECAUTIONS
Before taking this medication, tell your doctor or pharmacist if you are allergic to acetaminophen, caffeine, or butalbital; or to other barbiturates (e.g., phenobarbital) or xanthine derivatives (e.g., theophylline); or if you have any other allergies.
This medication should not be used if you have certain medical conditions. Before using this medicine, consult your doctor or pharmacist if you have: severe breathing problems (e.g., bronchopneumonia), a certain enzyme disorder (porphyria).Before using this medication, tell your doctor or pharmacist your medical history, especially of: liver disease, kidney disease, personal or family history of regular use/abuse of drugs/alcohol, mental/mood disorders, abdominal/stomach problems (e.g., stomach ulcer), heart disease (e.g., irregular heartbeat, recent heart attack).This drug may make you dizzy or drowsy. Do not drive, use machinery, or do any activity that requires alertness until you are sure you can perform such activities safely. Avoid alcoholic beverages.Liquid products may contain alcohol, sugar and/or aspartame. Caution is advised if you have diabetes, alcohol dependence, liver disease, phenylketonuria (PKU), or any other condition that requires you to limit/avoid these substances in your diet. Ask your doctor or pharmacist about using this product safely.This product contains acetaminophen, which may cause liver damage. Daily use of alcohol, especially when combined with acetaminophen, may increase your risk for liver damage. Avoid alcohol. Check with your doctor or pharmacist for more information.Before having surgery, tell your doctor or dentist that you are using this medication.Kidney function declines as you grow older. This medication is removed by the kidneys. Therefore, elderly people may be at greater risk for side effects while using this drug.During pregnancy, this medication should be used only when clearly needed. Using it for long periods or in high doses near the expected delivery date is not recommended because of possible harm to the unborn baby. Discuss the risks and benefits with your doctor. Infants born to mothers who have used this medication for an extended time may have withdrawal symptoms such as irritability, abnormal/persistent crying, vomiting, seizures, or diarrhea. Tell your doctor immediately if you notice any of these symptoms in your newborn.This drug passes into breast milk and could have undesirable effects on a nursing infant. Therefore, breast-feeding is not recommended while using this drug. Consult your doctor before breast-feeding.
FIORICET INTERACTIONS
Your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with them first.
This drug should not be used with the following medication because very serious interactions may occur: sodium oxybate.
If you are currently using the medication listed above, tell your doctor or pharmacist before starting this medication.
Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription/herbal products you may use, especially of: adenosine, anti-seizure drugs (e.g., carbamazepine, phenytoin), beta agonists (e.g., albuterol), drugs affecting liver enzymes that remove this medication from your body (such as macrolide antibiotics including erythromycin, cimetidine, disulfiram, valproic acid, fluvoxamine, MAO inhibitors including furazolidone, isocarboxazid, linezolid, moclobemide, phenelzine, procarbazine, rasagiline, selegiline, tranylcypromine), isoniazid, lithium, methoxyflurane, phenothiazines (e.g., chlorpromazine).
This drug can speed up the removal of other drugs from your body by affecting certain liver enzymes. These affected drugs include “blood thinners” (e.g., warfarin), cyclosporine, corticosteroids such as prednisone, estrogen, felodipine, metronidazole, quinidine, certain beta blockers such as metoprolol, theophylline, doxycycline.
Tell your doctor or pharmacist if you also take drugs that cause drowsiness such as certain antihistamines (e.g., diphenhydramine), medicine for sleep or anxiety (e.g., alprazolam, diazepam, zolpidem), muscle relaxants, narcotic pain relievers (e.g., codeine), psychiatric medicines (e.g., risperidone, amitriptyline, trazodone).
Check the labels on all your medicines (e.g., cough-and-cold products) because they may contain caffeine or drowsiness-causing ingredients. Also keep in mind that certain beverages (e.g., coffee, colas, tea) contain caffeine. Ask your pharmacist about using those products safely.
Acetaminophen is an ingredient in many nonprescription products and in some combination prescription medications. Read the labels carefully before taking other pain relievers, fever reducers, or cold products to see if they also contain acetaminophen. Consult your pharmacist if you are uncertain whether your other prescription or nonprescription products contain acetaminophen. (See also adult maximum daily dose information in Side Effects section.)
This medication may decrease the effectiveness of combination-type birth control pills. This can result in pregnancy. Ask your doctor or pharmacist for details, and discuss whether you should use additional reliable birth control methods while taking any of these drugs.
This medication may interfere with certain medical/laboratory tests (including urine 5-HIAA levels, urine VMA levels, urine catecholamine levels, dipyridamole-thallium imaging tests), possibly causing false test results. Make sure laboratory personnel and all your doctors know you use this drug.
This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist.
