Can I Take Medications With Phentermine?

medications with phentermine

Here at, we get a lot of questions about whether it’s safe to take medications with phentermine, which can include prescribed medications, supplements, and over-the-counter remedies for everyday problems such as headaches and indigestion. Here we explain all that you need to know about taking medications with phentermine, from specifically being prescribed medications to combine with phentermine, to the ways in which phentermine can interact with prescription medications, and how even over-the-counter remedies can reduce the effectiveness of phentermine.

Phentermine Combinations

In some cases, doctors will purposely prescribe medications with phentermine – these are known as phentermine combinations. The intention is that this combination of phentermine and another prescription medication maximizes the potential of the phentermine and increases the possibility of effective weight loss. One such combination is Phen-Pro, which is the name given to the combination of phentermine and a low dose of an anti-depressant, such as Prozac or Zoloft. The anti-depressant ingredient in Phen-Pro is not for the treatment of depression but rather is intended to help the phentermine work more effectively at promoting weight loss.

Another commonly prescribed phentermine combination is Qsymia, a combination of phentermine and topiramate, an anti-convulsant drug that can cause weight loss as a side effect. Qsymia is the brand name for this combination, but some doctors prefer to write two separate prescriptions for phentermine and topiramate, possibly as a way to save money for their patients so that their phentermine prescription is cheaper to fill. Phentermine can also be prescribed in other drug combinations, including with other weight loss drugs such as Belviq (known as Bel-Phen), anti-diabetic drugs like Glucophage XR, with other anti-convulsants such as Zonegran, or with Norepinephrine-Dopamine Reuptake Inhibitor (NDRIs) such as Wellbutrin SR. In certain cases these combinations may be prescribed to help treat other existing conditions such as sleep apnea, metabolic syndrome, and diabetes, while other combinations are intended to work together to increase the effectiveness of phentermine.

If you have been prescribed phentermine in combination with any other drug, it is important that your doctor explains to you why he or she has chosen this combination for you, what each medication does, how the two work together, and what possible interactions may arise as a result of the combination in order for you to know what to expect, both in terms of results and of possible side effects. Finally, it must be stressed that these combinations are only safe if specifically prescribed by a doctor. Even if you have individual prescriptions for both medications, without being prescribed a certain combination by a doctor who is aware of all of your medical conditions and current medications, harmful drug interactions may occur as a result of self-medicating phentermine combinations.

Taking Prescribed Medications With Phentermine

While taking phentermine, there is always the possibility that you may need to take other prescription medications at the same time for any number of health issues. These prescription medications fall into one of four categories: medications for existing conditions, medications for new conditions, short-term prescriptions, and birth control.

Medications For Existing Conditions

These types of medications would be those which you may have been taking long or short-term, but which you are taking at the time of being assessed for your suitability to take phentermine. It is imperative that you explain to your phentermine doctor that you are taking these medications and for how long you have been told to take them, especially if he or she is not your usual doctor or specialist. You should only be prescribed phentermine if it is deemed safe for you to take it alongside the other medication(s) you are taking, and even then, you should be informed of any possibilities of interactions between medications and how to recognize the symptoms of these. If you are being prescribed phentermine by a different doctor, it is also a good idea to tell any other prescribing doctors you may have that you are now taking phentermine – that way, your records with all the doctors you have contact with will be up to date, so that if any problems should arise they will all be in a better position to help you.

Medications For New Conditions

While you are taking phentermine, you may need to start taking medications for serious or long-term health problems that were not previously diagnosed. If the doctor who is prescribing this new medication is a different doctor then you must inform him or her that you are taking phentermine, as it is also crucial that you explain to your phentermine doctor about this new medication. It may be necessary for you to stop taking phentermine if there is a possibility that the two medications may cause a dangerous interaction. Alternatively, your phentermine prescription might be changed to a different dosage, or you may be advised to take a different weight loss medication.

medications with phentermine

Short-Term Prescriptions

Perhaps more likely than being prescribed new medications for more serious health problems, is the need to take a short course of antibiotics or other short-term prescription while taking phentermine. Most online sources state that phentermine does not interact with most antibiotics, but various allergy and breathing medications can cause interactions and unwanted side effects, so with this in mind, it is always crucial that you explain to your doctor that you are taking phentermine when you are prescribed any other medication, no matter how short-term it is. In addition, it might be advisable for you to take a break from phentermine while you are taking this medication for several reasons – to avoid unwanted side effects, to ensure that your medication works effectively, and so that the effects of phentermine are not compromised.

Birth Control Pills

If you are able to become pregnant then it is important to use some form of birth control when taking phentermine as phentermine cannot be taken by women who are pregnant or trying to become pregnant. Birth control pills have not been found to cause interactions with phentermine, although you should still ensure to inform your phentermine doctor about the contraceptive pill you are taking as there may be a need to change your pill in order to balance your hormones.

Taking Supplements And Non-Prescription Medications With Phentermine

While taking phentermine, in addition to prescribed medications, you may need to take over-the-counter (OTC) medications from time to time. Additionally, many people choose take additional supplements to boost health, help with the side effects of phentermine or to enhance the effectiveness of phentermine.

Non-Prescription Medications

We all take the occasional pill to help with every day ailments such as headaches or indigestion, but when taking phentermine there is the possibility that you may be more prone to headaches, nausea, dizziness, and constipation as some of the common phentermine side effects. Medical studies have found that drugs like aspirin will cause your urinary pH to become more acidic (meaning phentermine is excreted faster), so it is best to limit the amount of aspirin and other OTC medications you take while you are taking phentermine otherwise you will compromise the effectiveness of phentermine. When you are prescribed phentermine, it is a good idea to ask the doctor if he or she would recommend any specific medications for conditions like indigestion, headaches, or other pains that you may be prone to, as some may be more suitable than others when taken with phentermine.


Supplements such as 5-HTP or vitamin B12 injections are often prescribed alongside phentermine to maximize the effects of appetite suppression and energy-boosting. You may also prefer to take supplements, such as the multivitamin Phen Vites, in order to reduce other phentermine side effects such as low mood, lack of energy, and insomnia as opposed to taking additional medications such as sleeping pills or anti-depressants. In addition, these supplements help to maximize the effects of phentermine unlike some medications which can cause phentermine to be excreted from the body quicker, therefore lessening the weight-loss-boosting effects. If you feel that phentermine has stopped working or that it is not as effective as you had hoped, then you may wish to add a supplement such as Phen Caps. Phen Caps work like phentermine by suppressing appetite and boosting energy, but as Phen Caps contain different active ingredients, they are metabolized by the body differently and therefore help to boost the effectiveness of phentermine through different mechanisms in the body.

As with combining any medications, taking medications with phentermine is something that should only be done if it has been approved by a doctor. And, even if you have been told that it is fine to take a medication with phentermine, you should still remember to be extra vigilant about the possibility of additional side effects that may occur as a result of an interaction between the two medications, whether they have been prescribed for you or are non-prescription medications.

Are you currently taking any supplements or medications with phentermine? If so we would love to hear from you so please comment below!

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  1. It appears that the phentermine is exacerbating my age related insomnia. I have been taking an OTC sleep aid and melatonin for a while so getting to sleep is not a problem.
    But I wake up exactly 2 hrs later and have difficulty getting back to sleep plus leg irritation. This continues thru the night.
    I have experimented taking the phentermine as soon as I arise in the a.m. and cutting the dose to even single mg. amounts, but the insomnia continues.
    I have stopped the drug for a week and I sleep better but symptoms return with the first ( much reduced dose ) of phentermine
    I have a full RX of 37.5mg and want to continue using it. I am 63 and workout on average an hour a day.
    I have no chronic illnesses and don’t take other rx’s other than hormones.
    Would it be appropriate to ask my dr. for a rx’d sleep aid ?

    1. Hi Maggie,
      If these side effects are bothering you and continue despite modifications to your dosage then it could be a good idea to seek a solution from your doctor. Of course, he or she is in a position to know what’s best for you, which might be a prescription sleeping aid or another solution – either way, it’s best to ask.

    1. Hi Bonita,
      Usually supplements are fine to take with phentermine, but it could be a good idea to check with your doctor when you next have an appointment.

  2. Can I take Phentermine with my Pantoprazole, and Citalopram? I have taken the Phentermine years ago after having my babies, and it worked really well. Now I am 65 and I have been on this for 3 months and have only lost 10 lbs, with exercise. Wondering if my other meds are interfering with my results.

    1. Hi Brenda,
      You should always check if other meds will interfere with phentermine as the combination may cause an interaction. As for the 10lbs lost in 3 months, this is a slow rate but any loss is a step in the right direction, plus your age will be a factor. This article has some tips for over 50s losing weight to help you to put things in perspective: Good luck!

    1. Hey Brittney,
      Yes medication for a sore throat should be fine if it’s OTC, but if you get anything stronger from the doctor then you should make him or her aware that you’re taking phentermine in case there is a possibility of an interaction.

  3. Hi, my name is Mitchell. My Dr prescribed me the 37.5 phen and I was on it for almost 4 weeks. It was working great but unfortunately I pulled myself off due to concern. I have tachycardia (which my dr was aware) and I take medication to keep my heart rate down. At work one day last week, I noticed on my fitness watch that my walking hr was around 130 to 140. I was really nervous and made the decision to stop. Just wondering if I could get anyone else’s opinion on the matter. Thanks in advance.

  4. I was prescribed a DEXPAK (Dexamethosone-Oral; Commom brand name Decadron) with an antibiotic for a sinus infection. Can I take a DEXPAK while I am taking phentermine HCL?

    1. Hi Burks,
      It’s always best to ask your doctor about combining medications as we don’t know your medical history or whether these medications might interact with each other.

    1. Hi Leah,
      Oxyshred is a supplement so it should be fine to take it with phentermine but if you have any existing medical conditions then it could be a good idea to check with your doctor to make sure.

    1. Hi Megan,
      We don’t recommend meal replacement plans as these don’t help you to establish a healthier way of eating while you’re taking phentermine. It’s far better to eat real food so you can learn how to control hunger and keep your body fueled properly throughout the day.

    1. Hi Nella,
      We’re not qualified to answer questions like that – you have to check with your doctor before taking prescribed meds together.

    2. Hi Nella, did you find the answer to you question from your doctor?
      Just been prescribed eliquis 10mg but already on phentermine 30mg.
      Please let me know if you can shed light on this.
      Kindest Regards Sonya

      1. Hi Sonya. It’s very important that you speak with your prescribing doctor about all current and recent medications & supplements (and their dosages) before starting any new prescription. He or she would be best able to assess the appropriateness of combining these substances.

  5. Can you take phentermine with fenugreek and blessed thistle? I take a supplement containing both for pumping breast milk. I take the pills first thing in the a.m. And pump exclusively in the evening, but I take the fenugreek and blessed thistle capsules throughout the day. I take a half of 37.5 phentermine in the person a.m, and take the UpSpring milk flow capsules or drink throughout the day

    1. Hi Lizkeisha,
      If you are pumping breast milk to give to your baby you ABSOLUTELY MUST NOT TAKE PHENTERMINE. We explain here ( on the precautions page: “Use of phentermine (or other appetite suppressants) while breast-feeding is NOT recommended; it may pass into breast milk, causing unwanted effects in nursing babies. Consult your doctor for advice”. Please stop taking phentermine and speak to your doctor.

  6. Hello,

    I have allergies and really bad cramps when it’s “that time of the month.” Am I allowed to take Benadryl and Aleve while taking Adipex??

    1. Hi Beverly,
      It’s fine to take antihistamines while on phentermine as these would come under typical everyday types of medications, just like the contraceptive pill. Aleve is an anti-inflammatory as well as a pain-reliever so this is a good option for cramps, although we would recommend ibuprofen as the best medication for pain relief, and as it can be bought unbranded it is usually cheaper too.

  7. Hi There,
    Great article. Can I take phentermine along with Maca powder, it’s a herbal supplement for energy and libido. I find my energy and mood levels to be off while on phentermine.

    1. Hi Marshall,
      It’s fine to take supplements like Maca powder along with phentermine if you find that it helps with your energy levels and mood.

  8. I was prescribed phentermine to help with weight due to polycystic ovarian syndrome. Can I take phentermine with these supplements…fish oil, berberine, inositol, and soloray’s female hormone blend?

    1. Hi Eason,
      It is no problem to take phentermine alongside supplements and vitamins, and if these help with your PCOS too then this can only help your weight loss more.

    1. Hi Kirsten,
      You would have to ask your doctor about taking these together since Propronlol and Paxcil both seem to be prescription medications.

    1. Hi Dani,
      As the article explains, taking everyday medications like birth control alongside phentermine is fine. However, you might want to check with your doctor about whether changing your particular pill is necessary due to the effect phentermine can have on hormones.

  9. I am taking phen and topimax and have horrible congestion pain is there anything I can take to relieve the pressure?

    1. Hi Ronnie,
      You should check with your doctor to make sure about taking Restoril with phentermine.

    1. Hi Iarissa,
      Check with your doctor to make sure that it’s ok to take Tamiflu with phentermine.

    1. Hi Roes,
      OTC medications that you may need to take now and again are fine to take with phentermine, however, if these are medications that you take regularly and continuously then it is best to check with your doctor to make sure.

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