Fentanyl

FDA Drug Information • Also known as: Fentanyl, Fentanyl System

Brand Names: Fentanyl, Fentanyl System
Dosage Form: POWDER
Product Type: BULK INGREDIENT

⚠ Boxed Warning (Black Box)

WARNING: SERIOUS AND LIFE-THREATENING RISKS FROM USE OF FENTANYL TRANSDERMAL SYSTEM Addiction, Abuse, and Misuse Because the use of fentanyl transdermal system exposes patients and other users to the risks of opioid addiction, abuse, and misuse, which can lead to overdose and death, assess each patient’s risk prior to prescribing and reassess all patients regularly for the development of these behaviors and conditions [see Warnings and Precautions ( 5.1 )]. Life-threatening Respiratory Depression Serious, life-threatening, or fatal respiratory depression may occur with use of fentanyl transdermal system, especially during initiation or following a dose increase. To reduce the risk of respiratory depression, proper dosing and titration of fentanyl transdermal system are essential [see Warnings and Precautions ( 5.2 )] . Accidental Exposure Accidental exposure of even one dose of fentanyl transdermal system, especially in children, can result in a fatal overdose of fentanyl [see Warnings and Precautions ( 5.3 )]. Deaths due to an overdose of fentanyl have occurred when children and adults were accidentally exposed to fentanyl transdermal system. Strict adherence to the recommended handling and disposal instructions is for the utmost importance to prevent accidental exposure [see Warnings and Precautions ( 5.3 )] . Risks From Concomitant Use With Benzodiazepines Or Other CNS Depressants Concomitant use of opioids with benzodiazepines or other central nervous system (CNS) depressants, including alcohol, may result in profound sedation, respiratory depression, coma, and death. Reserve concomitant prescribing of fentanyl transdermal system and benzodiazepines or other CNS depressants for use in patients for whom alternative treatment options are inadequate [see Warnings and Precautions ( 5.4 ), Drug Interactions ( 7 )] . Neonatal Opioid Withdrawal Syndrome (NOWS) Advise pregnant women using opioids for an extended period of time of the risk of Neonatal Opioid Withdrawal Syndrome, which may be life-threatening if not recognized and treated. Ensure that management by neonatology experts will be available at delivery [see Warnings and Precautions ( 5.5 )]. Opioid Analgesic Risk Evaluation and Mitigation Strategy (REMS) Healthcare providers are strongly encouraged to complete a REMS-compliant education program and to counsel patients and caregivers on serious risks, safe use, and the importance of reading the Medication Guide with each prescription [see Warnings and Precautions ( 5.6 )]. Cytochrome P450 3A4 Interaction The concomitant use of fentanyl transdermal system with all cytochrome P450 3A4 inhibitors may result in an increase in fentanyl plasma concentrations, which could increase or prolong adverse drug effects and may cause potentially fatal respiratory depression. In addition, discontinuation of a concomitantly used cytochrome P450 3A4 inducer may result in an increase in fentanyl plasma concentration. Monitor patients receiving fentanyl transdermal system and any CYP3A4 inhibitor or inducer [see Warnings and Precautions ( 5.7 ) and Clinical Pharmacology ( 12.3 )]. Risk of Increased Fentanyl Absorption with Application of External Heat Exposure of the fentanyl transdermal system application site and surrounding area to direct external heat sources, such as heating pads or electric blankets, heat or tanning lamps, sunbathing, hot baths, saunas, hot tubs, and heated water beds may increase fentanyl absorption and has resulted in fatal overdose of fentanyl. Warn patients to avoid exposing the application site and surrounding area to direct external heat sources [see Warnings and Precautions ( 5.8 )] . WARNING: SERIOUS AND LIFE-THREATENING RISKS FROM USE OF FENTANYL TRANSDERMAL SYSTEM See full prescribing information for complete boxed warning. Fentanyl transdermal system exposes users to risks of addiction, abuse, and misuse, which can lead to overdose and death. Assess patient’s risk before prescribing and reassess regularly for these behaviors or conditions. ( 5.1 ) Serious, life-threatening, or fatal respiratory depression may occur, especially upon initiation or following a dosage increase. To reduce the risk of respiratory depression, proper dosing and titration of fentanyl transdermal system are essential. ( 5.2 ) Accidental exposure to fentanyl transdermal system, especially in children, can result in fatal overdose of fentanyl. ( 5.3 ) Concomitant use of opioids with benzodiazepines or other central nervous system (CNS) depressants, including alcohol, may result in profound sedation, respiratory depression, coma, and death. Reserve concomitant prescribing for use in patients for whom alternative treatment options are inadequate. ( 5.4 , 7 ) Advise pregnant women using opioids for an extended period of time of the risk of neonatal opioid withdrawal syndrome, which may be life-threatening if not recognized and treated. Ensure that management by neonatology experts will be available at delivery. ( 5.5 ) Healthcare providers are strongly encouraged to complete a REMS compliant education program and to counsel patients and caregivers on serious risks, safe use, and the importance of reading the Medication Guide with each prescription. ( 5.6 ) Concomitant use with CYP3A4 inhibitors (or discontinuation of CYP3A4 inducers) can result in a fatal overdose of fentanyl. ( 5.7 ) Exposure of the fentanyl transdermal system application site and surrounding area to direct external heat sources has resulted in fatal overdose of fentanyl. Warn patients to avoid exposing the fentanyl transdermal system application site and surrounding area to direct external heat sources. ( 5.8 )

Description

11 DESCRIPTION Fentanyl transdermal system contains fentanyl, an opioid agonist, for transdermal administration. The amount of fentanyl released from each system per hour is proportional to the surface area (25 mcg/hour per 10.5 cm 2 ). The composition per unit area of all transdermal system sizes is identical. Strength Nominal delivery rate per hour (mcg/hour) Size (cm 2 ) Fentanyl Content (mg) 12 Nominal delivery rate is 12.5 mcg/hour 5.35 1.38 25†† 10.7 2.76 37.5†† 16.05 4.14 50†† 21.4 5.52 62.5†† 26.75 6.90 75†† 32.1 8.28 87.5†† 37.45 9.66 100†† 42.8 11.04 The molecular weight of fentanyl base is 336.5 g/mol, and the empirical formula is C 22 H 28 N 2 O. The n-octanol: water partition coefficient is 860:1. The pKa is 8.4. The chemical name is N-Phenyl-N-(1-(2-phenylethyl)-4-piperidinyl) propanamide. The structural formula is: Fentanyl transdermal system is a rectangular transparent unit comprising a release liner and two functional layers. Proceeding from the outer surface toward the surface adhering to skin, these functional layers are: 1) a backing layer of polyethylene terephalate film; 2) a drug-in-adhesive layer. Before use, a release liner covering the drug-in-adhesive layer is removed and discarded. Structure Patch

What Is Fentanyl Used For?

1 INDICATIONS AND USAGE Fentanyl transdermal system is indicated for the management of severe and persistent pain in opioid-tolerant patients, that requires an opioid analgesic and that cannot be adequately treated with alternative options, including immediate-release opioids. Patients considered opioid-tolerant are those who are taking, for one week or longer, at least 60 mg morphine per day, 25 mcg transdermal fentanyl per hour, 30 mg oral oxycodone per day, 8 mg oral hydromorphone per day, 25 mg oral oxymorphone per day, 60 mg oral hydrocodone per day, or an equianalgesic dose of another opioid. Limitations of Use: Because of the risks of addiction, abuse, misuse, overdose, and death, which can occur at any dosage or duration and persist over the course of therapy [see Warnings and Precautions ( 5.1 )] , reserve opioid analgesics, including fentanyl transdermal system for use in patients for whom alternative treatment options are ineffective, not tolerated, or would be otherwise inadequate to provide sufficient management of pain. Fentanyl transdermal system is not indicated as an as-needed (prn) analgesic. Fentanyl transdermal system, an opioid agonist, is indicated for the management of severe and persistent pain in opioid-tolerant patients, that requires an opioid analgesic and that cannot be adequately treated with alternative options, including immediate-release opioids. ( 1 ) Patients considered opioid-tolerant are those taking, for one week or longer, at least 60 mg oral morphine per day, 25 mcg transdermal fentanyl per hour, 30 mg oral oxycodone per day, 8 mg oral hydromorphone per day, 25 mg oral oxymorphone per day, 60 mg oral hydrocodone per day or an equianalgesic dose of another opioid. ( 2.1 ) Limitations of use: Because of the risks of addiction, abuse, misuse, overdose and death, which can occur at any dosage or duration and persist over the course of therapy, reserve opioid analgesics, including fentanyl transdermal system for use in patients for whom alternative treatment options are ineffective, not tolerated, or would be otherwise inadequate to provide sufficient management of pain. ( 1, 5.1 ) Fentanyl transdermal system is not indicated as an as-needed (prn) analgesic. ( 1 )

Dosage and Administration

2 DOSAGE AND ADMINISTRATION Fentanyl transdermal system should be prescribed only by healthcare providers who are knowledgeable about the use of extended-release/long-actingopioids and how to mitigate the associated risks. ( 2.1 ) Use the lowest effective dosage for the shortest duration of time consistent with individual patient treatment goals. Reserve titration to higher doses of fentanyl transdermal system for patients in whom lower doses are insufficiently effective and in whom the expected benefits of using a higher dose opioid clearly outweigh the substantial risks. ( 2.1 , 5 ) Initiate the dosing regimen for each patient individually, taking into account the patient’s underlying cause and severity of pain, prior analgesic treatment and response, and risk factors for addiction, abuse, and misuse. ( 5.1 ) Respiratory depression can occur at any time during opioid therapy, especially when initiating and following dosage increases with fentanyl transdermal system. Consider this risk when selecting an initial dose and when making dose adjustments. ( 2.1 , 5.2 ) Discuss opioid overdose reversal agents and options for acquiring them with the patient and/or caregiver, both when initiating and renewing treatment with fentanyl transdermal system, especially if the patient has additional risk factors for overdose, or close contacts at risk for exposure and overdose. ( 2.2 , 5.1 , 5.2 , 5.4 ) Initial dose selection: consult conversion instructions. ( 2.3 ) Periodically reassess patients receiving fentanyl transdermal system to evaluate the continued need for opioid analgesics to maintain pain control, for the signs or symptoms of adverse reactions, and for the development of addiction, abuse, or misuse. ( 2.4 ) Each transdermal system is intended to be worn continuously for up to 72 hours. ( 2.3, 2.7 ) Adhere to instructions concerning administration and disposal of fentanyl transdermal system. ( 2.7 , 2.8 ) Mild to moderate hepatic and renal impairment: Initiate treatment with one half the usual starting dose, titrate slowly, and monitor for signs of respiratory and central nervous system depression. ( 2.5 , 2.6 ) Do not rapidly reduce or abruptly discontinue fentanyl transdermal system in a physically-dependent patient because rapid reduction or abrupt discontinuation of opioid analgesics has resulted in serious withdrawal symptoms, uncontrolled pain, and suicide. ( 2.9 , 5.21 ) 2.1 Important Dosage and Administration Instructions Fentanyl transdermal system should be prescribed only by healthcare professionals who are knowledgeable about the use of extended-release/long-acting opioids and how to mitigate the associated risks. Due to the risk of respiratory depression, fentanyl transdermal system is only indicated for use in patients who are already opioid-tolerant. Discontinue or taper all other extended-release opioids when beginning fentanyl transdermal system therapy. As fentanyl transdermal system is only for use in opioid-tolerant patients,...

Side Effects (Adverse Reactions)

6 ADVERSE REACTIONS The following serious adverse reactions are discussed elsewhere in the labeling: Addiction, Abuse, and Misuse [see Warnings and Precautions ( 5.1 )] Life-Threatening Respiratory Depression [see Warnings and Precautions ( 5.2 )] Accidental Exposure [see Warnings and Precautions ( 5.3 )] Interactions with Benzodiazepines or Other Central Nervous System Depressants [see Warnings and Precautions ( 5.4 )] Neonatal Opioid Withdrawal Syndrome [see Warnings and Precautions ( 5.5 )] Opioid-Induced Hyperalgesia and Allodynia [see Warnings and Precautions ( 5.10 )] Serotonin Syndrome [see Warnings and Precautions ( 5.11 )] Adrenal Insufficiency [see Warnings and Precautions ( 5.13 )] Severe Hypotension [see Warnings and Precautions ( 5.14 )] Gastrointestinal Adverse Reactions [see Warnings and Precautions ( 5.19 )] Seizures [see Warnings and Precautions ( 5.20 )] Withdrawal [see Warnings and Precautions ( 5.21 )] Most common adverse reactions (≥5%) are nausea, vomiting, somnolence, dizziness, insomnia, constipation, hyperhidrosis, fatigue, feeling cold, anorexia, headache, and diarrhea. ( 6 .) To report SUSPECTED ADVERSE REACTIONS, call Ingenus Pharmaceuticals, LLC at 1-877-748-1970 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trial Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice. The safety of fentanyl transdermal system was evaluated in 216 patients who took at least one dose of fentanyl transdermal system in a multicenter, double-blind, randomized, placebo-controlled clinical trial of fentanyl transdermal system. This trial examined patients over 40 years of age with severe pain induced by osteoarthritis of the hip or knee and who were in need of and waiting for joint replacement. The most common adverse reactions (≥5%) in a double-blind, randomized, placebo-controlled clinical trial in patients with severe pain were nausea, vomiting, somnolence, dizziness, insomnia, constipation, hyperhidrosis, fatigue, feeling cold, and anorexia. Other common adverse reactions (≥5%) reported in clinical trials in patients with chronic malignant or nonmalignant pain were headache and diarrhea. Adverse reactions reported for ≥1% of fentanyl transdermal system-treated patients and with an incidence greater than placebo-treated patients are shown in Table 3. The most common adverse reactions that were associated with discontinuation in patients with pain (causing discontinuation in ≥1% of patients) were depression, dizziness, somnolence, headache, nausea, vomiting, constipation, hyperhidrosis, and fatigue. Table 3: Adverse Reactions Reported by ≥1% of Fentanyl Transdermal System-treated Patients and With an Incidence Greater Than Placebo-treated Patients in 1 Double-Blind, Placebo-Controlled Clinical Trial of Fentanyl Transdermal System System/Organ Class Adverse Reaction Fentanyl Transdermal System % (N=216) Placebo % (N=200) Cardiac disorders Palpitations 4 1 Ear and labyrinth disorders Vertigo 2 1 Gastrointestinal disorders Nausea 41 17 Vomiting 26 3 Constipation 9 1 Abdominal pain upper 3 2 Dry mouth 2 0 General disorders and administration site conditions Fatigue 6 3 Feeling cold 6 2 Malaise 4 1 Asthenia 2 0 Edema peripheral 1 1 Metabolism and nutrition disorders Anorexia 5 0 Musculoskeletal and connective tissue disorders Muscle spasms 4 2 Nervous system disorders Somnolence 19 3 Dizziness 10 4 Psychiatric disorders Insomnia 10 7 Depression 1 0 Skin and subcutaneous tissue disorders Hyperhidrosis 6 1 Pruritus 3 2 Rash 2 1 Adverse reactions not reported in Table 3 that were reported by ≥1% of fentanyl transdermal system-treated adult and pediatric patients (N=1854) in 11 controlled and uncontrolled clinical trials of fentanyl transdermal system used for the treatment of chronic...

Drug Interactions

7 DRUG INTERACTIONS Table 6 includes clinically significant drug interactions with fentanyl transdermal system. Table 6: Clinically Significant Drug Interactions with Fentanyl Transdermal System Inhibitors of CYP3A4 Clinical Impact: The concomitant use of fentanyl transdermal system and CYP3A4 inhibitors can increase the plasma concentration of fentanyl, resulting in increased or prolonged opioid effects particularly when an inhibitor is added after a stable dose of fentanyl transdermal system is achieved [see Warnings and Precautions ( 5.7 )]. After stopping a CYP3A4 inhibitor, as the effects of the inhibitor decline, the fentanyl transdermal system plasma concentration will decrease [see Clinical Pharmacology ( 12.3 )] , resulting in decreased opioid efficacy or a withdrawal syndrome in patients who had developed physical dependence to fentanyl. Intervention: If concomitant use is necessary, consider dosage reduction of fentanyl transdermal system until stable drug effects are achieved. Evaluate patients at frequent intervals for respiratory depression and sedation. If a CYP3A4 inhibitor is discontinued, consider increasing the fentanyl transdermal system dosage until stable drug effects are achieved. Evaluate for signs of opioid withdrawal. Examples Macrolide antibiotics (e.g., erythromycin), azole-antifungal agents (e.g. ketoconazole), protease inhibitors (e.g., ritonavir), grapefruit juice CYP3A4 Inducers Clinical Impact: The concomitant use of fentanyl transdermal system and CYP3A4 inducers can decrease the plasma concentration of fentanyl [see Clinical Pharmacology ( 12.3 )] , resulting in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence to fentanyl [see Warnings and Precautions ( 5.7 )] . After stopping a CYP3A4 inducer, as the effects of the inducer decline, the fentanyl plasma concentration will increase [see Clinical Pharmacology ( 12.3 )] , which could increase or prolong both the therapeutic effects and adverse reactions, and may cause serious respiratory depression. Intervention: If concomitant use is necessary, consider increasing the fentanyl transdermal system dosage until stable drug effects are achieved. Evaluate for signs of opioid withdrawal. If a CYP3A4 inducer is discontinued, consider fentanyl transdermal system dosage reduction and evaluate patients at frequent intervals for signs of respiratory depression and sedation. Examples: Rifampin, carbamazepine, phenytoin Benzodiazepines and Other Central Nervous System (CNS) Depressants Clinical Impact: Due to additive pharmacologic effect, the concomitant use of benzodiazepines or other CNS depressants, including alcohol, can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death. Intervention: Reserve concomitant prescribing of these drugs for use in patients for whom alternative treatment options are inadequate. Limit dosages and durations to the minimum required. Inform patients and...

Contraindications

4 CONTRAINDICATIONS Fentanyl transdermal system is contraindicated in: patients who are not opioid-tolerant. the management of acute or intermittent pain, or in patients who require opioid analgesia for a short period of time. the management of post-operative pain, including use after out-patient or day surgeries, (e.g., tonsillectomies). the management of mild pain. patients with significant respiratory depression [see Warnings and Precautions ( 5.12 )] . in patients with acute or severe bronchial asthma in an unmonitored setting or in the absence of resuscitative equipment [see Warnings and Precautions ( 5.12 )] . in patients with known or suspected gastrointestinal obstruction, including paralytic ileus [see Warnings and Precautions ( 5.19 )] . in patients with hypersensitivity to fentanyl (e.g. anaphylaxis) or any components of the transdermal system [see Adverse Reactions ( 6.2 )] . Opioid non-tolerant patients. ( 4 ) Acute or intermittent pain, postoperative pain, mild pain. ( 4 ) Significant respiratory depression. ( 4 ) Acute or severe bronchial asthma in an unmonitored setting or in absence of resuscitative equipment. ( 4 ) Known or suspected gastrointestinal obstruction, including paralytic ileus. ( 4 ) Known hypersensitivity to fentanyl or any of the components of the transdermal system. ( 4 )

Pregnancy and Breastfeeding

8.1 Pregnancy Risk Summary Use of opioid analgesics for an extended period of time during pregnancy may cause neonatal opioid withdrawal syndrome [see Warnings and Precautions ( 5.5 )] . Available data with fentanyl transdermal system in pregnant women are insufficient to inform a drug-associated risk for major birth defects and miscarriage. In animal reproduction studies, fentanyl administration to pregnant rats during organogenesis was embryocidal at doses within the range of the human recommended dosing. When administered during gestation through lactation fentanyl administration to pregnant rats resulted in reduced pup survival and developmental delays at doses within the range of the human recommended dosing. No evidence of malformations were noted in animal studies completed to date [see Data] . The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively. Clinical Considerations Fetal/Neonatal Adverse Reactions Use of opioid analgesics for an extended period of time during pregnancy for medical or nonmedical purposes can result in physical dependence in the neonate and neonatal opioid withdrawal syndrome shortly after birth. Neonatal opioid withdrawal syndrome presents as irritability, hyperactivity and abnormal sleep pattern, high pitched cry, tremor, vomiting, diarrhea, and failure to gain weight. The onset, duration, and severity of neonatal opioid withdrawal syndrome vary based on the specific opioid used, duration of use, timing and amount of last maternal use, and rate of elimination of the drug by the newborn. Observe newborns for symptoms of neonatal opioid withdrawal syndrome and manage accordingly [see Warnings and Precautions ( 5.5 )] . Labor...

Overdosage

10 OVERDOSAGE Clinical Presentation Acute overdose with fentanyl transdermal system can be manifested by respiratory depression, somnolence progressing to stupor or coma, skeletal muscle flaccidity, cold and clammy skin, constricted pupils, and, in some cases, pulmonary edema, bradycardia, hypotension, hypoglycemia, partial or complete airway obstruction, atypical snoring and death. Marked mydriasis rather than miosis may be seen with hypoxia in overdose situations [see Clinical Pharmacology ( 12.2 )] . Toxic leukoencephalopathy has been reported after opioid overdose and can present hours, days, or weeks after apparent recovery from the initial intoxication. Treatment of Overdose Give primary attention to the reestablishment of a patent airway and institution of assisted or controlled ventilation, if needed. Employ other supportive measures (including oxygen and vasopressors) in the management of circulatory shock and pulmonary edema as indicated. Cardiac arrest or arrhythmias will require advanced life support measures. Once stable, examine the patient and ensure that all fentanyl transdermal systems have been removed. For clinically significant respiratory or circulatory depression secondary to opioid overdose, administer an opioid overdose reversal agent such as naloxone or nalmefene. Because the duration of opioid reversal is expected to be less than the duration of action of fentanyl in fentanyl transdermal system, carefully monitor the patient until spontaneous respiration is reliably reestablished. After fentanyl transdermal system removal, serum fentanyl concentrations decline gradually, falling about 50% in approximately 20-27 hours. Therefore, management of an overdose must be monitored accordingly, at least 72 to 96 hours beyond the overdose. In an individual physically dependent on opioids, administration of the recommended usual dosage of the opioid overdose reversal agent will precipitate an acute withdrawal syndrome. The severity of the withdrawal...

How Supplied

16 HOW SUPPLIED/STORAGE AND HANDLING Fentanyl transdermal system is supplied in cartons containing 5 individual child-resistant packaged systems. See chart for information regarding individual systems. Fentanyl Transdermal System Dose (mcg/hour) System Size (cm 2 ) Fentanyl Content (mg) NDC Number for Blister Containing Individual System NDC Number for Carton Containing 5 Systems Fentanyl Transdermal System-12* 5.35 1.38 50742-549-01 50742-549-05 Fentanyl Transdermal System-25 10.7 2.76 50742-550-01 50742-550-05 Fentanyl Transdermal System-37.5 16.05 4.14 50742-551-01 50742-551-05 Fentanyl Transdermal System-50 21.4 5.52 50742-552-01 50742-552-05 Fentanyl Transdermal System-62.5 26.75 6.90 50742-553-01 50742-553-05 Fentanyl Transdermal System-75 32.1 8.28 50742-554-01 50742-554-05 Fentanyl Transdermal System-87.5 37.45 9.66 50742-555-01 50742-555-05 Fentanyl Transdermal System-100 42.8 11.04 50742-556-01 50742-556-05 * This lowest strength is designated as 12 mcg/hour (however, the actual strength is 12.5 mcg/hour) to distinguish it from a 125 mcg/hour strength that could be prescribed by using multiple transdermal systems. Store in original unopened pouch. Store up to 25°C (77°F); excursions permitted from 15°C to 30°C (59°F to 86°F). Store fentanyl transdermal system securely and dispose of properly [ see Patient Counseling Information ( 17 ) ].

About This Information

This drug information is sourced from FDA-approved labeling via the openFDA database. It is intended for educational and reference purposes only. This is not medical advice. Always consult your healthcare provider before making decisions about medication. Drug information may be updated by the FDA; check with your pharmacist for the most current information.

What are side effects?

Side effects are unwanted reactions that can occur when taking a medication. They range from mild (headache, nausea) to severe (allergic reactions, organ damage). Not everyone experiences side effects, and severity varies. Report any concerning side effects to your doctor.

What are drug interactions?

Drug interactions occur when a medication is affected by another drug, food, or supplement. Interactions can make medications less effective or cause dangerous side effects. Always tell your doctor about all medications and supplements you take.