Synthroid makes the heart beat faster?

klone, MSN, RN · Aug 30, 2010

I have no experience with Synthroid, either personally or clinically. However, I was able to answer the question simply by using critical thinking. Synthroid is used for hypothyroidism = increases thyroid function = increases metabolic functions.

Critical thinking skills are not something that we only have to use in nursing school. :-)

clemmm78, RN · Aug 30, 2010

I have no experience with Synthroid, either personally or clinically. However, I was able to answer the question simply by using critical thinking. Synthroid is used for hypothyroidism = increases thyroid function = increases metabolic functions.
Critical thinking skills are not something that we only have to use in nursing school. :-)

That was my reaction when I read the question. Considering why synthroid is given, it's a natural that it would speed up things.

citylights89, BSN, RN · Aug 31, 2010

I finally filled my prescription and started the med today...on my birthday of all days! We'll see what happens. So far so good, but I know it takes awhile. I have to take my iron later today too.

NooNieNursie · Aug 31, 2010

Ok so I have a patient and she was recently put on a Synthroid and I noticed that her heart rate is faster than usual,also she takes another newly prescribed drug for better breathing Singular and lately her chest X-ray showed some abnormalities (nodules) When I saw her on my last visit I took a look at her morning VS (I go see her before lunch around 11-nish and in the morning her caregiver take her BP electronically and also does accu check and her pulse was 110 and diastolic BP over 100.When I did my own set of vital signs the BP was normal 120/80,and pulse was 95.She was asymptomatic.

The thyroid gland regulates metabolism, including sympathetic nervous system activity thus affecting heart rate. Bradycardia is a sign of hypothyroidism, tachycardia is a sign of hyperthyroidism. If a patient has untreated thyroid disease their heartrate will increase when given theraputic synthroid. However, if the patient is pushed into hyperthyroid by the synthroid, they may experience an abnormal elevation in heart rate.

The physician should be following the patient's TSH t3 t4 if she is just starting this medication.

I would relay this finding to the physician (newly on synthroid, now presenting tachycardia).

belliot2 · Aug 31, 2010

I have been hypo-for over 19 years. Its not alot, but enough I do have symptoms if not taking the Synthroid.

I did have a benign tumor and 1/2 my thyroid removed in 1992. Then it was fine for several years- (but about 30% of people have benign tumors grow back- and should be followed up for this). I have had tumors grow back recently- but all thyroid tumors grow SLOWLY- so it takes time for it to impact you. These tumors grow off the natural T3,T4 that your thyroid puts out, which is why your norms can be only slightly off , yet you have lots of symptoms....

Yes, it can increase your heart rate, but it should be putting it within normal range. If it is exceeding normal limits, it is too much. I have had heart palpitations, but that was a sign that it was too much.

Actually, the first sign its too much synthroid is not being able to fall asleep at night within 10-15 minutes.

So, ask your patients if they have any trouble getting to sleep and staying asleep. Do they experience any time they feel their heart is racing? report these symptoms to their MD, likely they will want to re-test T3,T4, TSh.