Pulse 36. increased Levothyroxine to 50 mcg on Tuesday.

[Earlyriser]

Didn’t feel good today so took my pulse on a Cardiio app and it’s 36. I’m a bit panicky now as that seems really low. Could it be the increase in levothyroxin. What should I do now.

[bantam12]

You should check it manually because apps aren't accurate.

[Earlyriser in reply to bantam12]

Just checked on an oximetry and it’s 36

[bantam12 in reply to Earlyriser]

Unless you are super fit a resting rate of 36 is to low, normal is 60-100bpm.

If you have symptoms of bradycardia best to call 111 for advice.

[Earlyriser in reply to bantam12]

It has gone up a bit so I Will wait an hour and ring 111 if there’s no further increase. Thank you bantam12. Good to know you were there xx

[SlowDragon Administrator]

Which brand of levothyroxine are you currently taking

Is this same brand as when on 25mcg?

It takes at least 5-7 days for first increase in dose to kick in, can make you feel worse initially

Takes 6-8 weeks for dose increase in levothyroxine to have full effect

Dose of levothyroxine is increased slowly upwards in 25mcg steps until on full replacement dose

Essential to regularly retest vitamin D, folate, ferritin and B12 ..these frequently need supplementing to bring to optimal levels

What vitamin supplements are you currently taking?

Recommended on here that all thyroid blood tests should ideally be done as early as possible in morning and before eating or drinking anything other than water .

Last dose of Levothyroxine 24 hours prior to blood test. (taking delayed dose immediately after blood draw).

This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip, best not mentioned to GP or phlebotomist)

Is this how you do your tests?

guidelines on dose levothyroxine by weight

Even if we don’t start on full replacement dose, most people need to increase levothyroxine dose slowly upwards in 25mcg steps (retesting 6-8 weeks after each increase) until on full replacement dose

NICE guidelines on full replacement dose

nice.org.uk/guidance/ng145/...

1.3.6

Consider starting levothyroxine at a dosage of 1.6 micrograms per kilogram of body weight per day (rounded to the nearest 25 micrograms) for adults under 65 with primary hypothyroidism and no history of cardiovascular disease.

gp-update.co.uk/Latest-Upda...

Traditionally we have tended to start patients on a low dose of levothyroxine and titrate it up over a period of months.

RCT evidence suggests that for the majority of patients this is not necessary and may waste resources.

For patients aged >60y or with ischaemic heart disease, start levothyroxine at 25–50μg daily and titrate up every 3 to 6 weeks as tolerated.

For ALL other patients start at full replacement dose. For most this will equate to 1.6 μg/kg/day (approximately 100μg for a 60kg woman and 125μg for a 75kg man).

If you are starting treatment for subclinical hypothyroidism, this article advises starting at a dose close to the full treatment dose on the basis that it is difficult to assess symptom response unless a therapeutic dose has been trialled.

A small Dutch double-blind cross-over study (ArchIntMed 2010;170:1996) demonstrated that night time rather than morning dosing improved TSH suppression and free T4 measurements, but made no difference to subjective wellbeing. It is reasonable to take levothyroxine at night rather than in the morning, especially for individuals who do not eat late at night.

BMJ also clear on dose required

bmj.com/content/368/bmj.m41

bestpractice.bmj.com/topics...

Recommend getting a Fitbit or similar to give printable record of resting heart rate.

[humanbean]

Could it be the increase in levothyroxin.

Unlikely.

Bradycardia - slow heart rate - is a common symptom of hypothyroidism. Taking Levo at the appropriate dose for you is likely to raise your heart rate to a much more normal level.

[Earlyriser]

Sorry everyone I’ve just got back from accident and emergency. They have checked me over and said I have an erratic heartbeat which did settle and to see my gp to have a monitor if it happens again. I can’t thank you all enough for your kindness and support. Feeling much better now and very grateful to you xx

[naturalista]

Holy crap!

Over here we give Levothyroxine to shut down overdoses of thyroid (on rare occasion). L-thyroxine is NOT thyroid hormone, but a synthetic analog. The heart used the most thyroid hormone seeing it has to make 3x the energy of other domestic cells. If it can’t make the energy...it slows down. Find a new doctor. Don’t be a hero and die for the quack who’s been mismanaging you! Good luck

[McPammy]

When my Levothyroxine was increased in 2018 it went over range. My heart rate dropped to 36. I wear a fit bit. I felt exhausted and very sleepy. Once the Levo was reduced my heart rate went back to my normal 56/58 bpm. When this happened in 2018 I was admitted to hospital to the cardiac ward. Lots of tests done checking for bradycardia. I have no heart issues at all. It was too much Levothyroxine. I’m now on T3 medication also as we found out I’m a really poor converter. If my T3 gets too high in the range my heart rate drops too. Only yesterday I felt a bit dizzy and felt slightly over medicated and my heart rate had dropped to 42bpm. Yesterday I took a little less T3 and today I don’t feel dizzy and my resting heart rate is 55bpm. For me it’s an alarm to let me know my medication is too high either T4 or T3.