Before taking fentanyl,
tell your doctor and pharmacist if you are allergic to fentanyl patches, injection, nasal spray, tablets, lozenges, or films; any other medications; or any of the ingredients in fentanyl sublingual spray. Ask your pharmacist or check the Medication Guide for a list of the ingredients.
tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, and nutritional supplements you are taking or plan to take. Be sure to mention the medications listed in the IMPORTANT WARNING section and any of the following medications: antihistamines; barbiturates such as phenobarbital; buprenorphine (Buprenex, Subutex, in Suboxone); butorphanol; dextromethorphan (found in many cough medications; in Nuedexta); efavirenz (in Atripla, Sustiva); lithium (Lithobid); medications for migraine headaches such as almotriptan (Axert), eletriptan (Relpax), frovatriptan (Frova), naratriptan (Amerge), rizatriptan (Maxalt), sumatriptan (Alsuma, Imitrex, in Treximet), and zolmitriptan (Zomig); mirtazapine (Remeron); medications for seizures such as carbamazepine (Tegretol, Teril), oxcarbazepine (Trileptal), and phenytoin (Dilantin, Phenytek); modafinil (Provigil); nalbuphine; naloxone (Evzio, Narcan); nevirapine (Viramune); oral steroids such as dexamethasone, methylprednisolone (Medrol), and prednisone (Rayos); pioglitazone (Actos); rifampin (Rifadin, Rimactane, in Rifamate, in Rifater); rifabutin (Mycobutin); 5HT3 serotonin blockers such as alosetron (Lotronex), dolasetron (Anzemet), granisetron (Kytril), ondansetron (Zofran, Zuplenz), or palonosetron (Aloxi); selective serotonin-reuptake inhibitors such as citalopram (Celexa), escitalopram (Lexapro), fluoxetine (Prozac, Sarafem, in Symbyax), fluvoxamine (Luvox), paroxetine (Brisdelle, Prozac, Pexeva), and sertraline (Zoloft); serotonin and norepinephrine reuptake inhibitors such as desvenlafaxine (Khedezla, Pristiq), duloxetine (Cymbalta), milnacipran (Savella), and venlafaxine (Effexor); trazodone (Oleptro); tricyclic antidepressants ('mood elevators') such as amitriptyline, clomipramine (Anafranil), desipramine (Norpramin), doxepin (Silenor), imipramine (Tofranil), nortriptyline (Pamelor), protriptyline (Vivactil), and trimipramine (Surmontil); or troglitazone (Rezulin). Also tell your doctor or pharmacist if you are taking or receiving any of the following medications or if you have stopped taking them within the past two weeks: monoamine oxidase (MAO) inhibitors including isocarboxazid (Marplan), linezolid (Zyvox), methylene blue, phenelzine (Nardil), selegiline (Eldepryl, Emsam, Zelapar), and tranylcypromine (Parnate). Many other medications may also interact with fentanyl, so be sure to tell your doctor about all the medications you are taking, even those that do not appear on this list. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
tell your doctor what herbal products you are taking, especially St. John's wort and tryptophan.
tell your doctor if you or anyone in your family drinks or has ever drunk large amounts of alcohol or uses or has ever used street drugs or excessive amounts of prescription medications. Also tell your doctor if you have or have ever had sores, ulcers, or swelling in your mouth, a head injury, a brain tumor, a stroke, or any other condition that caused high pressure inside your skull; slowed heartbeat or other heart problems; difficulty urinating; breathing problems such as asthma and chronic obstructive pulmonary disease (COPD; a group of lung diseases that includes chronic bronchitis and emphysema); or kidney or liver disease.
tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. If you become pregnant while using fentanyl, call your doctor.
you should know that this medication may decrease fertility in men and women. Talk to your doctor about the risks of using fentanyl sublingual spray.
if you are having surgery, including dental surgery, tell the doctor or dentist that you are using fentanyl.
you should know that fentanyl may make you drowsy or dizzy. Do not drive a car or operate machinery until you know how this medication affects you.
you should know that fentanyl may cause dizziness, lightheadedness, and fainting when you get up too quickly from a lying position. This is more common when you first start using fentanyl. To avoid this problem, get out of bed slowly, resting your feet on the floor for a few minutes before standing up.
you should know that fentanyl sublingual spray may cause constipation. Talk to your doctor about changing your diet and using other medications to treat or prevent constipation.