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Synthroid (Levothyroxine) Questions and Drug Interactions

CAUTION: Take levothyroxine early in the morning at least 30 minutes before breakfast with a full glass of water. Your physician should order a yearly blood level to be certain the proper strength is being taken. Make sure all your health care providers have a complete list of your medications, including over-the-counter medications, herbals and vitamins.

Also called: Elequine, Levoxyl, Levothroid, Unithroid

Synthroid drug interactions are first, followed by general Synthroid questions.

Can I take Synthroid (levothyroxine) with:

Adderall? Yes. Take Adderall after breakfast.
Adderall and Librax? Yes. Take Adderall in the morning. Take Librax near mealtimes. Librax can cause drowsiness.
Afrin, Plavix (Clopidogrel), Lipitor and Sintrom (Warfarin)? Afrin is fine unless you have high blood pressure. There are drug interactions between levothyroxine and Plavix and Sintrom. Plavix and Sintrom are both blood thinners.
Alcohol? Yes. Alcohol will not interact with Synthroid, if you have a drink later in the day or a cocktail with dinner.
Allegra D? Yes. Take the Allegra D with or after breakfast.
Alprazolam (Xanax)? Yes. Take alprazolam only as needed. It can make you drowsy.
Amoxicillin? Yes. Taken 2-3 times daily, amoxicillin doses should be dosed evenly throughout the day. Take until finished.
Angiotensin II Receptor Antagonists? Yes.


Yes. Take aspirin with food (after breakfast).
Benadryl? Yes. The diphenhydramine can cause drowsiness.
Buscopan and Adalat? Yes. Take Adalat (nifedipine) at the same time each day. Buscopan (scopolamine) can cause extreme dry mouth, so drink plenty of water.
Dimetapp? Yes.
Errin Birth Control Pills? Yes. Many women take their birth control pills after breakfast to reduce the chance of stomach upset.
Hoodia, Ultra 90 or some other type of fat burner? No. Talk with your doctor about alternatives for weight reduction. Exercise and diet are far more effective, safer and compatible with your prescriptions.
Klonopin (Clonazepam)? Yes. They may be taken together. Klonopin can cause drowsiness. Avoid alcohol, as this will increase the risk of sedation.
L-arginine Yes. Let me remind you that normally any thyroid product is taken early in the mornings, before breakfast. Not at the same time with other medications.
Loratadine  -- 3-4 hours later? Yes, several hours later.
Lipitor (Atorvastatin)?
The references I checked do not show any drug interaction. I have never seen a problem.  If you are concerned, take Lipitor with your evening meal.
Lisinopril first thing in the morning? Yes. Do NOT take any vitamin, mineral or herbal product with Synthroid. Have your blood pressure checked regularly, and your physician should order a blood level at least yearly for your thyroid.
Magnesium Maleate? Yes. Take thyroid medication at least 30 minutes before breakfast. Take magnesium with food, avoiding any calcium product if you take a calcium replacement for osteoporosis.


Yes. Take melatonin at bedtime.
Metformin, Mucinex DM and Advil? Yes. Drink plenty of water with the Mucinex DM (guaifenesin with dextromethorphan). Take metformin (Glucophage) with breakfast and dinner.
Motrin? Yes. Motrin (ibuprofen) should be taken after food or milk to avoid stomach distress. Do not take them at the same time for this reason.
Mucinex DM? Yes. Mucinex can be taken any time, but with plenty of water.
Norethisterone and a Travel Probiotic?  Yes.
NyQuil? If you have heart disease, oral decongestants like pseudoephedrine (Sudafed) can increase the effects of the thyroid hormone, and cause palpitations and rapid heart beat. Talk to the physician who prescribed the Levoxyl about over-the-counter cold medications with decongestants before taking any of these. Always take Levoxyl early in the morning.
Orlistat? Yes. Take orlistat with meals to hinder the absorption of fat.
Over-the-Counter Medication for Sinus Trouble? When you have thyroid problems, your body can be affected in many ways. Ask your endocrinologist about allergy, cold or sinus medication. The reason is that taking excessive cold and sinus medicines, the heart medicine amiodarone, iodine containing products, or certain contrast dyes given before some X-rays may expose you to too much iodine, which may make you at greater risk for developing hypothyroidism, especially if you have had thyroid problems. So if you are stable with your current dose of thyroid medication, taking these could change the amount of replacement medication you need. If the doctor makes a suggestion, most allergy and sinus medications do not have interactions with thyroid replacement drugs.
Prednisone? Yes, but not at the same time. Take prednisone after food or milk exactly as prescribed. Make sure your physician orders a thyroid blood level every year to ensure the dose is correct.
Prilosec? Yes. If you take Prilosec once daily, take it before dinner. If you take it twice daily, then an hour between the two is fine.
Pseudoephedrine? Yes, but do not take pseudoephedrine if you have high blood pressure or heart problems.
Red rice yeast (600mg) to lower LDL and melatonin (3mg) with L-Theanine (25mg) to help me sleep? Yes. My concern with herbal drugs: how do you know what's in the product, how do you know there is not any additional herb or other substance in the product? Herbal supplements are not regulated by the Food and Drug Administration (FDA), as are other medications (see our Herbal Supplement Quiz). Obtain your herbal products from a reputable supplier.
Tylenol Extra-Strength?
Yes. Limit your daily amount of Tylenol to 3000mg or less. That would be no more than 6 Extra-Strength Tylenol per day.
Tylenol Severe Allergy?

Yes. Take the cold medication an hour or more after taking levothyroxine. Drink plenty of fluids with the cold medication.

Wellbutrin (Bupropion) at the Same Time in the Morning?

Yes, between 30 and 60 minutes before breakfast.

Be sure to take levothyroxine early in the morning at least 30 minutes before breakfast with a full glass of water.

Can I take Synthroid with rabeprazole, docusate and vitamin D all together in morning?
There are no direct drug interactions between Synthroid (levothyroxine), rabeprazole (Aciphex), docusate (Colace) and Vitamin D (cholecalciferol). The Synthroid is best taken early in the morning, at least one-half hour or more, before breakfast. I would also suggest taking the rabeprazole before breakfast. I would suggest taking these at least one-half hour apart, the thyroid drug first, to get proper absorption of the thyroid medication. The Vitamin D is better absorbed if taken with food. The docusate should be taken with a full glass of water. I would suggest to take these with breakfast.

Can I take lamotrigine, clonazepam and Synthroid together in the morning?
Yes. The Synthroid is normally taken early in the morning, by itself, a half hour or so before breakfast.

Can I take Topamax, amitriptyline, premarin, and levothyroxine all at the same time before I go to bed?
Normally, levothyroxine (Synthroid) is taken early in the mornings, at least one-half hour before breakfast. Recently, I've been seeing more doctors prescribing the thyroid replacement therapies at bedtime. As long as you remember to take this each day, on an empty stomach.
There may be possible slight drug interactions between amitriptyline (Elavil), Topamax (topiramate) and Premarin (conjugated estrogens). The amitriptyline and Topamax may cause you to feel drowsy or more tired when taking these drugs together. Notify your doctor if you notice any new or worsening side effects, such as confusion, constipation, dizziness, difficulty with urination, dry mouth and eyes, changes in vision, or irregular or fast heartbeat , nausea, extreme drowsiness or other unusual effect while you are taking amitriptyline and Topamax together. Topamax may also reduce the effectiveness of estrogen hormones like Premarin. Taking the Premarin with the levothyroxine may reduce the effectiveness of the thyroid hormone. Your health care provider will monitor your thyroid function as needed. Report any signs of low thyroid, like feeling cold, depression, or unusual weight gain. Most patients that take these medications do not have these problems. 

Can I take allergy or sinus meds if I take Synthroid daily?
Yes. There are no direct drug interactions between Synthroid (levothyroxine) and many of the common allergy/sinus medications including short and long acting antihistamines, decongestants of oral and nasal type, dextromethorphan (DM) for cough and the expectorant guaifenesin.

I had 80 percent of my thyroid removed due to cancer. I was prescribed 100MCG of Levothyroxine and I just don't feel normal, very little energy. Also, can I take Zoloft 50MG with this drug?
There may be an interaction between levothyroxine (Synthroid) and Zoloft (sertraline). Zoloft may decrease the actions of Thyroid hormones like levothyroxine. Your physician should monitor your thyroid function as needed. Report any signs of low thyroid function, like sleepiness, feeling cold, depression, or unusual weight gain to your doctor. Take the levothyroxine early each morning, and the Zoloft later in the day.

I take 5mg Proscar, 25mg atenolol, 20mg Lipitor. I always take together in the morning when I wake up. Have not had any problems. My doctor put me on levothyroxine sodium 50mcg tablets once a day for thyroid condition. Can I take it with my other meds at the same time?
Thyroid medication is normally taken as soon as you awake in the morning, before breakfast. The other three, Proscar (finasteride), atenolol (Tenormin) and Lipitor (atorvastatin) may be taken together after breakfast. The only possible interaction involves the levothyroxine (Synthroid) and the atenolol (and any beta blocker). The effects of atenolol may be decreased by thyroid hormones in some patients, but interactions are not very common. These drugs are often used together. Report palpitations or rapid heart beat, if they occur, to your physician.

When taking Synthroid 50mg, how far apart should I take other medications: MiraLAX and Amitiza?
Synthroid should always be taken early in the morning before breakfast with a full glass of water. I would suggest taking the other two at least two hours after breakfast.

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