Fioricet can cause side effects that may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be awake and alert.

Avoid drinking alcohol. It may increase your risk of liver damage while taking acetaminophen.

Ask a doctor or pharmacist before using any other cold, allergy, pain, or sleep medication. Acetaminophen (sometimes abbreviated as APAP) is contained in many combination medicines. Taking certain products together can cause you to get too much acetaminophen which can lead to a fatal overdose. Check the label to see if a medicine contains acetaminophen or APAP.

While you are taking Fioricet, avoid taking diet pills, caffeine pills, or other stimulants (such as ADHD medications) without your doctor’s advice.

Medicines that interact with Fioricet may either decrease its effect, affect how long it works for, increase side effects, or have less of an effect when taken with Fioricet. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.

Common medications that may interact with Fioricet include:

  • antidepressants, such as tricyclic antidepressants (eg, amitriptyline), monoamine oxidase inhibitors (eg, isocarboxazid, phenelzine, and tranylcypromine), or SSRIs (eg, fluoxetine, sertraline)
  • anticonvulsants, such as carbamazepine, divalproex, lamotrigine, phenytoin, phenobarbital, or primidone
  • antipsychotics (such as butyrophenones, phenothiazines, or thioxanthenes) and atypical antipsychotics (eg, olanzapine, quetiapine, ziprasidone)
  • any medication that may cause drowsiness, such as amphetamines, benzodiazepines (eg, diazepam, lorazepam), first-generation antihistamines (such as doxylamine or promethazine), metoclopramide, or opioids (such as codeine, fentanyl or morphine)
  • buprenorphine
  • cannabis
  • cyclosporine
  • dextromethorphan
  • duloxetine
  • heart medications such as diltiazem or verapamil
  • HIV medications such as ritonavir
  • migraine medications, such as ergotamine or dihydroergotamine
  • muscle relaxants, such as cyclobenzaprine
  • naltrexone
  • other medications that contain acetaminophen or an opioid either in combination or as the sole ingredient
  • pentazocine
  • prilocaine
  • rifampin
  • sodium oxybate
  • tamsulosin
  • tramadol
  • warfarin.