Phrenilin (Oral)

Butalbital and acetaminophen combination is used to relieve symptoms of tension (or muscle contraction) headaches.

Butalbital is part of a group of medicines called barbiturates. They work in the central nervous system (CNS) to produce their effects.

Acetaminophen is used to relieve pain and lower fever in patients. It does not become habit-forming when used for a long time. However, taking large doses of acetaminophen may cause other unwanted effects, including serious liver damage. Although rare, using acetaminophen has been linked to liver transplantation and death, usually at high doses and when multiple acetaminophen-containing products have been used.

This medicine is available only with your doctor's prescription.

It is very important for your doctor to monitor your progress while you are using this medicine, especially during the first 24 to 72 hours of treatment. This helps your doctor see if the medicine is working correctly and decide if you should keep taking it. Blood tests may be needed to check for unwanted effects.

This medicine may cause serious skin reactions (for example, acute generalized exanthematous pustulosis, Stevens-Johnson syndrome, toxic epidermal necrolysis). Contact your doctor immediately if you experience blistering, peeling, or loosening of the skin, chills, cough, diarrhea, itching, joint or muscle pain, red irritated eyes, red skin lesions, often with a purple center, sore throat, sores, ulcers, or white spots in the mouth or on the lips, or unusual tiredness or weakness.

This medicine may cause serious allergic reactions, including anaphylaxis, which can be life-threatening and require immediate medical attention. Call your doctor right away if you have chest tightness, cough, dizziness, fast heartbeat, hives, rash, itching, puffiness or swelling of the eyelids, or around the eyes, face, lips, or tongue, trouble breathing or swallowing, or unusual tiredness or weakness while using this medicine.

This medicine may make you feel dizzy, drowsy, confused, or disoriented. Do not drive or do anything else that could be dangerous until you know how this medicine affects you.

Do not suddenly stop taking this medicine without first checking with your doctor. Your doctor may want you to gradually reduce the amount you are using before stopping completely. This can help prevent a possible worsening of your condition and reduce the chances of withdrawal symptoms such as confusion about time, place, or person, hallucinations, holding false beliefs that cannot be changed by fact, seizures, or unusual excitement, nervousness, or restlessness.

This medicine may be habit-forming. If you feel that the medicine is not working as well, do not take more than your prescribed dose. Call your doctor for instructions.

Before you have any medical tests, inform the medical doctor in charge that you are taking this medicine. The results of some tests may be affected by this medicine.

This medicine will increase the effects of alcohol and other CNS depressants (medicines that can make you drowsy or less alert). Some examples of CNS depressants are antihistamines or medicine for allergies or colds, sedatives, tranquilizers, or sleeping medicine, other prescription pain medicine or narcotics, medicine for seizures or barbiturates, muscle relaxants, or anesthetics, including some dental anesthetics. Additionally, there may be a greater risk of liver damage if you consume 3 or more alcoholic beverages while taking acetaminophen. Do not drink alcoholic beverages, and check with your doctor before taking any of these medicines while using this medicine.

If you think you or someone else may have taken an overdose of this medicine, seek emergency help immediately. Signs of an overdose include: black, tarry stools, bloody or cloudy urine, blurred vision, change in consciousness, chills, confusion, dark urine, difficult or painful urination, dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position, fever, headache, irregular, fast or slow, or shallow breathing, itching, light-colored stools, loss of appetite, loss of consciousness, nausea, pale or blue lips, fingernails, or skin, sleepiness, stomach pain, sudden decrease in the amount of urine, sweating, trouble breathing, unpleasant breath odor, unusual tiredness or weakness, vomiting of blood, or yellow eyes or skin.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

In deciding to use a medicine, you need to think about the risks and benefits. This is a choice you will make with your doctor. For this medicine, consider the following:

Allergies

Tell your doctor if you have ever had any unusual or allergic reactions to this medicine or any other medicines. Also inform your health care professional about any other allergies you have, such as to foods, dyes, preservatives, or animals. For over-the-counter products, read the label or package ingredients carefully.

Pediatric

Appropriate studies have not been done on how butalbital and acetaminophen combination affects children younger than 12 years. Safety and effectiveness have not been established.

Geriatric

Appropriate studies have not shown any specific problems in elderly patients that would limit the usefulness of butalbital and acetaminophen combination. However, older patients are more likely to have age-related issues with the liver, kidneys, or heart, which may require caution and adjustments in the dose for those taking this medicine.

Breast Feeding

There are no adequate studies in women to determine the risk to infants when using this medication while breastfeeding. Weigh the potential benefits against the risks before taking this medication while breastfeeding.

Interactions with Medicines

Some medicines should not be used together at all, while others may be used together even if an interaction might occur. In these cases, your doctor may want to adjust the dose or take other precautions. It is very important that your healthcare professional knows if you are taking any of the medicines listed below. The following interactions have been selected based on their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is usually not recommended, but may be necessary in some situations. If both medicines are prescribed together, your doctor may adjust the dose or frequency of one or both medicines.

• Alfentanil
• Alprazolam
• Amobarbital
• Anisindione
• Aprobarbital
• Barbital
• Butabarbital
• Calcium Oxybate
• Carisoprodol
• Chloral Hydrate
• Chlordiazepoxide
• Chlorzoxazone
• Clarithromycin
• Clonazepam
• Clorazepate
• Dantrolene
• Darunavir
• Diazepam
• Dicumarol
• Doxorubicin
• Doxorubicin Hydrochloride Liposome
• Drospirenone
• Esketamine
• Estazolam
• Eterobarb
• Ethchlorvynol
• Ethinyl Estradiol
• Etonogestrel
• Flunitrazepam
• Flurazepam
• Halazepam
• Heptabarbital
• Hexobarbital
• Imatinib
• Isocarboxazid
• Isoniazid
• Ketazolam
• Linezolid
• Lorazepam
• Lormetazepam
• Magnesium Oxybate
• Medazepam
• Mephenesin
• Mephobarbital
• Meprobamate
• Metaxalone
• Methocarbamol
• Methohexital
• Methylene Blue
• Midazolam
• Nifedipine
• Nitrazepam
• Norethindrone
• Norgestimate
• Norgestrel
• Oxazepam
• Ozanimod
• Pentobarbital
• Phenelzine
• Phenindione
• Phenobarbital
• Phenprocoumon
• Piperaquine
• Pixantrone
• Pneumococcal 13-Valent Vaccine, Diphtheria Conjugate
• Potassium Oxybate
• Prazepam
• Primidone
• Procarbazine
• Quazepam
• Rasagiline
• Safinamide
• Secobarbital
• Selegiline
• Sodium Oxybate
• Temazepam
• Thiopental
• Tranylcypromine
• Trazodone
• Triazolam
• Ulipristal
• Zotepine

Using this medicine with any of the following medicines may increase the risk of certain side effects, but using both drugs may be necessary for your treatment. If both medicines are prescribed together, your doctor may adjust the dose or frequency of one or both medicines.

• Acenocoumarol
• Carbamazepine
• Fosphenytoin
• Lixisenatide
• Ospemifene
• Phenytoin
• Prednisone
• St John's Wort
• Warfarin
• Zidovudine

Interactions with Food/Tobacco/Alcohol

Some medicines should not be taken around meal times or with certain foods due to possible interactions. Using alcohol or tobacco with some medicines may also lead to interactions. The following interactions have been selected based on their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following is usually not recommended, but may be unavoidable in some cases. If used together, your doctor may adjust the dose or frequency of this medicine, or provide special instructions about food, alcohol, or tobacco use.

• Ethanol
• Tobacco

Using this medicine with any of the following may increase the risk of certain side effects, but may be unavoidable in some situations. If used together, your doctor may adjust the dose or frequency of this medicine, or give you special instructions about food, alcohol, or tobacco use.

• Cabbage

Other Medical Problems

Having other medical conditions may affect the use of this medicine. Be sure to inform your doctor if you have any other medical issues, especially:

• Alcohol or drug abuse or dependence, or history of—Use with caution. May increase risk for more serious side effects.

• Kidney disease or
• Liver disease—Use with caution. The effects may be greater due to slower removal of the medicine from the body.

• Porphyria (enzyme problem)—Should not be used in patients with this condition.

Along with its necessary effects, a medicine may cause some unwanted effects. Not all of these side effects may happen, but if they do, they may need medical attention.

Check with your doctor right away if any of the following side effects occur:

More common

• Dizziness
• Lightheadedness
• Sleepiness
• Trouble breathing

Less common

• Anxiety
• Black, tarry stools
• Bleeding gums
• Blistering, peeling, or loosening of the skin
• Blood in the urine or stools
• Chest tightness
• Chills
• Cough or hoarseness
• Diarrhea
• Difficulty swallowing
• Discouragement
• Dry mouth
• Excitement
• Fainting
• False or unusual sense of well-being
• Fast, pounding, or irregular heartbeat or pulse
• Feeling sad or empty
• Headache
• Heavy eyelids
• High energy
• Hives, itching, skin rash
• Hot spells
• Hyperventilation
• Irregular heartbeats
• Irritability
• Joint or muscle pain
• Lack of appetite
• Loss of interest or pleasure
• Lower back or side pain
• Mental confusion
• Nervousness
• Painful or difficult urination
• Pinpoint red spots on the skin
• Puffiness or swelling of the eyelids or around the eyes, face, lips or tongue
• Red irritated eyes
• Red skin lesions, often with a purple center
• Restlessness
• Seizures
• Shaky feeling
• Sluggishness
• Sore throat
• Sores, ulcers, or white spots in the mouth or on the lips
• Trouble concentrating
• Trouble sleeping
• Unusual bleeding or bruising
• Unusual tiredness or weakness

Incidence not known

• Dark urine
• Loss of appetite
• Nausea or vomiting
• Severe stomach pain
• Yellow eyes or skin

Get emergency help immediately if any of the following symptoms of overdose happen:

Symptoms of overdose

• Black, tarry stools
• Bloody or cloudy urine
• Blurred vision
• Change in consciousness
• Chills
• Confusion
• Dark urine
• Difficult or painful urination
• Dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
• Fever
• Headache
• Irregular, fast or slow, or shallow breathing
• Itching
• Light-colored stools
• Loss of appetite
• Loss of consciousness
• Nausea
• Pale or blue lips, fingernails, or skin
• Sleepiness
• Stomach pain
• Sudden decrease in amount of urine
• Sweating
• Trouble breathing
• Unpleasant breath odor
• Unusual tiredness or weakness
• Vomiting of blood
• Yellow eyes or skin

Some side effects may happen that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Your healthcare professional may also be able to tell you how to prevent or reduce some of these side effects. Check with your healthcare professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Less common

• Bloated
• Constipation
• Continuing ringing or buzzing or other unexplained noise in the ears
• Dry mouth
• Earache
• Excess air or gas in the stomach or intestines
• Full feeling
• Hearing loss
• Heartburn
• Increased sweating
• Indigestion
• Leg pain
• Passing gas
• Stuffy nose

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

In the U.S.

• Cephadyn
• Orbivan CF
• Phrenilin
• Phrenilin Forte

Available Dosage Forms:

• Tablet
• Capsule

Therapeutic Class: Butalbital/Acetaminophen Combination

Pharmacologic Class: Barbiturate

Take this medicine only as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered. If too much of this medicine is taken for a long time, it may become habit-forming and cause mental or physical dependence. Also, large amounts of acetaminophen may cause liver damage if taken for a long time.

Carefully check the labels of all other medicines you are using, because they may also contain acetaminophen. It is not safe to use more than 4 grams (4,000 milligrams) of acetaminophen in one day (24 hours), as this may increase the risk for serious liver problems.

Dosing

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

• For tension headaches:: For oral dosage form (capsules): Adults and children 12 years of age and older—1 or 2 capsules every 4 hours. However, the dose is usually not more than 6 capsules per day. Do not exceed 4 grams (4000 milligrams) of acetaminophen (Tylenol®) per day. Children younger than 12 years of age—Use and dose must be determined by your doctor. For oral dosage form (tablets): Adults and children 12 years of age and older—1 or 2 tablets every 4 hours as needed. However, the dose is usually not more than 6 tablets per day. Do not exceed 4 grams (4000 milligrams) of acetaminophen (Tylenol®) per day. Children younger than 12 years of age—Use and dose must be determined by your doctor.

Storage

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.