Acetaminophen drug interactions with different drugs explained

Fioricet contains a combination of acetaminophen, butalbital, and caffeine Acetaminophen is a pain reliever and fever reducer.

Butalbital is in a group of drugs called barbiturates. It relaxes muscle contractions involved in a tension headache. Caffeine is a central nervous system stimulant. It relaxes muscle contractions in blood vessels to improve blood flow.

Fioricet is used to treat tension headaches that are caused by muscle contractions.

If you are using any narcotic drug, it is always better to know about its drug interactions with other products. This can help you use the drug safely and avoid using the products or medicines that have adverse effects when used with your drug.

A product that can interact with Acetaminophen is ketoconzole. This medication can interfere with some laboratory test resulting in incorrect lab results. Let your laboratory personnel know that you are using this drug.

Drug Interactions

Acetaminophen with Isoniazid

The information shared is generalized and not given as a medical advice. Consult your doctor before using or discontinuing any drug or starting any treatment.

Medical warning

Moderate risks. These drugs can results in some risks when consumed together. Contact your doctor for detailed information.

How the drug interaction occurs

Isoniazid can affect how the liver processes the medicine Acetaminophen.


The quantity of metabolite of Acetaminophen in the liver can increase or cause liver damage.

Let your doctor know that you are using these two medicines together. Your health care provider might suggest you to try some other pain reliever while consuming Isoniazid.  Also inform your doctor if you notice any signs of liver problems like nausea, vomiting, dark urine, yellowing of eyes or abdominal pain. Do not change, start or stop the current dosage on your own without talking to your doctor.


Acetaminophen with Busulfan

Medical warning

Moderate risks. These drugs can lead to some risks when used together. Contact your health care provider for detailed information.

How the drug interaction occurs

Acetaminophen can slow down the speed of your body to removing busulfan.

What can happen?

It might take a long time for your body to eliminate busulfan.

What should you know about the interaction (Acetaminophen with Busulfan)?

Inform your doctor that you are using the two medicines together. Your doctor might advise you to stop using Acetaminophen for three days prior to busulfan therapy and a few days after the busulfan therapy. If you are not sure whether your medicine consists of Acetaminophen, check with your pharmacist.

If you notice any signs like chills, fever, sore throat abdominal pain, yellowing of skin or eyes, vomiting, depression, mood changes, anxiety, hallucinations, irregular heartbeat, confusion and muscle cramps. Contact your doctor immediately.

Acetaminophen- Selected Anticoagulants

Medical warning

Moderate risks. These drugs can lead to some risks when used together. Contact your health care provider for detailed information.

How the drug interaction occurs

Acetaminophen when taken regularly can affect the ability of your body to make clots.

What can happen?

You may notice an increased bleeding including bleeding gums, nosebleed, dark stools and unusual bruising.

What should you know about the interaction?

Let your doctor know that you are using the two medicines together, the dose of Acetaminophen you use and how frequently you use Acetaminophen. You doctor may ask you that he wants to check the INR values closely. If you have stopped taking Acetaminophen, let your doctor know about it. If you observe any signs of nose bleeding, unusual bruising etc., immediately contact your doctor.

Fioricet Drug Interactions that you should know

Drug interactions can change the effects of how the medication works for you or increase the risk of unwanted side effects.

Maintain a list of all other products you use apart from Fioricet. These products can be non prescription or prescription drugs, herbal supplements etc., and share the list with your pharmacist or doctor. Do not try to stop, change the dosage or start any of the medicines without consulting your doctor.

Some products that can interact with Fioricet comprise of

  1. Oxybate
  2. Sodium
  3. Darunavir
  4. Drugs that affect liver enzymes and flush out the medication from the body like macrolide antibiotics such as valproic acid, rasagiline,cimetedine, disulfiram, erythromycin MAO inhibitors, fluvoxamine, methylene blue, phenelzine moclobemide, ), isoniazid, procarbazine, selegiline, phenothiazines, tranylcypromine, lithium etc.,

Fioricet accelerates the elimination of other drugs from the body by affecting some liver enzymes. These drugs that are affected include, blood thinners like estrogen, doxycycline, felodipine, theophylline etc.,

Also let your doctor know about any other drowsiness causing drugs that you are using like anti-seizure drugs or antihistamines or medicines for anxiety or sleeping disorders, muscle relaxants, psychiatric medicines  or narcotic pain relievers.

Check the labels before you buy any medicines for yourself even for cough or cold because they may contain caffeine or other components that cause drowsiness. Remember some beverages also contain caffeine like colas, coffee, tea and energy drinks. Consult your pharmacist to know how you can use these products safely.

Fioricet can also reduce the potency of birth control hormonal pills, ring or patch. This can lead to pregnancy. Consult your pharmacist or doctor if you should use other birth control options while using this medicine. Also let your doctor know if you experience breakthrough bleeding or new spotting as this can be the indication that your birth control technique is not functioning properly.

Fioricet can also interfere with certain laboratory or medical tests, resulting in giving incorrect test results. Make sure your doctor or laboratory personnel know that you are using this drug.

Alcohol and Fioricet

Check with your doctor regarding alcohol consumption while taking Fioricet. The medicine might increase the intoxication effects of alcohol. Drinking when you are on Fioricet may result in liver damage due to acetaminophen.

It is very important to know about the drug interaction with all other medications you are using including supplements and simple medications used for cold and cough. Knowing about the contents of medications you are using, you can easily know about the risk linked to drug interactions. You can also let your doctor know about the other medications you are using so that your doctor helps you know Fioricet interactions with those medicines.

You can avoid the risks linked to drug interactions and in case you experience any unusual symptoms, you can connect with your doctor. Though Fioricet is quite useful, it comes with a lot of restrictions too, you just need to take care of those limitations to get better results. Try to get maximum benefits from your drug.