Phentermine interactions
Overview
Phentermine (Adipex-P) is a stimulant weight-loss medicine. In our database it has 10 known interactions with common medicines and substances: 0 serious, 8 that need caution and 2 minor.
Use caution 8 interactions
Alcohol and ADHD stimulants strain the heartAmphetamine salts
Two stimulants at onceBupropion
Higher seizure riskDayQuil
Can raise blood pressure and heart rateLisdexamfetamine
Two stimulants at onceMethylphenidate
Two stimulants at oncePhenylephrine
Can raise blood pressure and heart ratePseudoephedrine
Can raise blood pressure and heart rate
Minor 2 interactions
No known interaction found
Our rules found no interaction between Phentermine and: Acetaminophen, Acyclovir, Albuterol, Allopurinol, Alprazolam, Amitriptyline, Amlodipine, Amoxicillin, Amoxicillin-clavulanate, Apixaban, Aripiprazole, Ashwagandha, Aspirin, Atenolol, Atorvastatin, Azithromycin, Baclofen, Birth control pills, Bismuth subsalicylate, Buprenorphine-naloxone, Buspirone, Calcium carbonate, Cannabis, Carvedilol, Celecoxib, Cephalexin, Cetirizine, Ciprofloxacin, Citalopram, Clindamycin, Clonazepam, Clonidine, Clopidogrel, Codeine, Colchicine, Creatine, Cyclobenzaprine, Dextromethorphan, Diazepam, Diclofenac, Digoxin, Diphenhydramine, Doxycycline, Doxylamine, Duloxetine, Empagliflozin, Escitalopram, Esomeprazole, Estradiol, Famotidine, Fexofenadine, Finasteride, Fish oil, Fluconazole, Fluoxetine, Furosemide, Gabapentin, Glipizide, Grapefruit juice, Guaifenesin, Hydrochlorothiazide, Hydrocodone, Hydroxychloroquine, Hydroxyzine, Ibuprofen, Insulin, Iron supplements, Isotretinoin, Kratom, Lamotrigine, Levetiracetam, Levofloxacin, Levothyroxine, Lisinopril, Lithium, Loperamide, Loratadine, Lorazepam, Losartan, Magnesium, Meclizine, Melatonin, Meloxicam, Metformin, Methocarbamol, Methotrexate, Methylprednisolone, Metoprolol, Metronidazole, Mirtazapine, Montelukast, Morphine, Naltrexone, Naproxen, Nicotine, Nitrofurantoin, NyQuil, Omeprazole, Ondansetron, Oseltamivir, Oxycodone, Pantoprazole, Paroxetine, Paxlovid, Potassium supplements, Pravastatin, Prednisone, Pregabalin, Probiotics, Promethazine, Propranolol, Quetiapine, Rivaroxaban, Rosuvastatin, Semaglutide, Sertraline, Sildenafil, Simvastatin, Spironolactone, St. John's wort, Sulfamethoxazole-trimethoprim, Sumatriptan, Tadalafil, Tamsulosin, Tirzepatide, Tizanidine, Topiramate, Tramadol, Trazodone, Turmeric, Valacyclovir, Venlafaxine, Vitamin D, Warfarin, Zinc, Zolpidem.
Add at least two medicines, supplements or alcohol.
Sources
Source: FDA label for Phentermine on DailyMed (effective 2026-08), plus the labels of each interacting medicine.
This list covers the 147 medicines and substances in our database. It is not a complete list of every possible interaction. Always tell your doctor and pharmacist about every medicine, supplement and herbal product you take.