[Rach74]

#1059013

I am 37 yrs old and recently had a recurrence of my hyperthyroidism symptoms (I have a 4 month old baby).
The first time I discovered my hyperthyroidism when my first daughter was one year and was diagnosed with graves (she is now 6). I was put on PTU – 150mg per day (as i wanted to get pregnant again). Within a week I started feeling better and then within 3 months I was down to 1 tablet a day which I continued for a number of years after which I went into remission.

My levels were a bit higher this time and I have been put on 200mg of PTU a day a well as a low dose of a beta blocker. I had my levels of free t4 an free t3 tested again yesterday (5 days after starting medication) as I was due to have surgery for an ovarian cyst. They rang today and said that my levels have actually increased, so they have cancelled the surgery.

I am feeling a bit better despite the increase in levels, however am wondering if this might be because of the beta blocker.

Anyway, I was just wondering if it is possible for the levels to increase before they decrease or is it likely that I will have to increase my meds? I have another blood test booked in a week by the GP, but it will be a while before I can see the endo.
Any thoughts would be greatly appreciated.

Rachael

[Bobbi]

#1171561

The beta blocker is not known to act on thyroid levels — it just helps to mask some of the symptoms, and to provide a bit of protection for the heart from the effects of too much thyroid hormone.

[adenure]

#1171562

Hi Rachael,

I hope everything works out for you. I have a 5 month old and was diagnosed with Graves (for the 1st time) 6 weeks ago- I’m on methimazole instead of PTU (I’m not planning on anymore pregnancies). I also have 3 other boys too. As a side, I was curious if ovarian cysts always need to be removed? I had some pain (on and off- depending on the day) near my ovary and I wasn’t sure what it was. I’m going to my Ob/ Gyn at the end of May to check it out. I didn’t know if surgery was required to resolve a cyst or not. Thanks!

Alexis

[Rach74]

#1171563

Alexis – Not all ovarian cysts have to be removed, mine is just particularly large (7cm) so there is risk of twisting and it has been there a while – they noticed it during early pregnancy scans. However it is non urgent surgery which is why they were able to cancel due to the hyperthyroidism. Ovarian cysts are fairly normal and can come and go with your natural cycle and small ones are usually just left unless there is something unusual about them.

Bobbi – thanks, yes perhaps the beta blocker is masking my symptoms despite the thyroid levels increasing.

I am still wondering if it is possible that my levels could stabilise on the current dosage of PTU (given that the test showing higher thyroid level was done so soon after I started the medication) or if I am likely to have to increase my current dosage?
I am breastfeeding, so was really hoping that the current dosage would be enough.

Thanks,
Rachael

[adenure]

#1171564

Hi again!

I’m breastfeeding as well (on 5 mg. of methimazolel daily). Here is Dr. Hale’s info. on ATD’s (both Methimazole & PTU) and breastfeeding.

-Alexis

METHIMAZOLE

Trade Names: Tapazole

Uses: Antithyroid agent

LRC: L3

AAP: Maternal Medication Usually Compatible with Breastfeeding

Methimazole, carbimazole, and propylthiouracil are used to inhibit the secretion of thyroxine. Carbimazole is a prodrug of methimazole and is rapidly converted to methimazole. Milk levels of methimazole depend on maternal dose but appear too low to produce clinical effect. In one study of a patient receiving 2.5 mg methimazole every 12 hours, the milk/serum ratio was 1.16, and the dose per day was calculated at 16-39 µg methimazole.[1] This was equivalent to 7-16% of the maternal dose. In a study of 35 lactating women receiving 5 to 20 mg/day of methimazole, no changes in the infant thyroid function were noted in any infant, even those at higher doses.[2] Further, studies by Lamberg in 11 women, who were treated with the methimazole derivative carbimazole (5-15 mg daily, equal to 3.3 -10 mg methimazole), found all 11 infants had normal thyroid function following maternal treatments.[3] Thus, in small maternal doses, methimazole may also be safe for the nursing mother. In a study of a woman with twins who was receiving up to 30 mg carbimazole daily, the average methimazole concentration in milk was 43 µg/L.[4] The average plasma concentrations in the twin infants were 45 and 52 ng/mL, which is below therapeutic range. Methimazole milk concentrations peaked at 2-4 hours after a carbimazole dose. No changes in thyroid function in these infants were noted. In a large study of over 134 thyrotoxic lactating mothers and their infants. Methimazole therapy was initiated at 10-30 mg/day for one month, and reduced to 5-10 mg/day subsequently. Even at methimazole doses of 20 mg/day, no changes in infant TSH, T4 or T3 were noted in over 12 months of study.[5] The authors conclude that both PTU and methimazole can safely be administered during lactation. However, during the first few months of therapy, monitoring of infant thyroid functioning is recommended.

Pregnancy Risk Category: D, D

Lactation Risk Category: L3, L3

Adult Concerns: Hypothyroidism, hepatic dysfunction, bleeding, drowsiness, skin rash, nausea, vomiting, fever.

Pediatric Concerns: None reported in several studies, but propylthiouracil may be a preferred choice in breastfeeding women.

Drug Interactions: Use with iodinated glycerol, lithium, and potassium iodide may increase toxicity.

Relative Infant Dose Range: 2.3%

Adult Dose: 5-30 mg daily.

Alternatives: Propylthiouracil

T½ = 6-13 hours M/P = 1.0
PHL = PB = 0%
Tmax = 1 hour Oral = 80-95%
MW = 114 pKa = 11.64
Vd =
References
1. Tegler L, Lindstrom B. Antithyroid drugs in milk. Lancet 1980; 2(8194):591.
2. Azizi F. Effect of methimazole treatment of maternal thyrotoxicosis on thyroid function in breast-feeding infants. J Pediatr 1996; 128(6):855-858.
3. Lamberg BA, Ikonen E, Osterlund K, Teramo K, Pekonen F, Peltola J, Valimaki M. Antithyroid treatment of maternal hyperthyroidism during lactation. Clin Endocrinol (Oxf) 1984; 21(1):81-87.
4. Rylance GW, Woods CG, Donnelly MC, Oliver JS, Alexander WD. Carbimazole and breastfeeding. Lancet 1987; 1(8538):928.
5. Azizi F, Khoshniat M, Bahrainian M, Hedayati M. Thyroid function and intellectual development of infants nursed by mothers taking methimazole. J Clin Endocrinol Metab 2000; 85(9):3233-3238.

PROPYLTHIOURACIL

Trade Names: PTU, Propyl-Thyracil

Uses: Antithyroid

LRC: L2

AAP: Maternal Medication Usually Compatible with Breastfeeding

Propylthiouracil reduces the production and secretion of thyroxine by the thyroid gland. Only small amounts are secreted into breastmilk. Reports thus far suggest that levels absorbed by infant are too low to produce side effects.[1] In one study of nine patients given 400 mg doses, mean serum and milk levels were 7.7 mg/L and 0.7 mg/L respectively.[2] No changes in infant thyroid have been reported. PTU is the best of antithyroid medications for use in lactating mothers. Monitor infant thyroid function (T4, TSH) carefully during therapy.

Pregnancy Risk Category: D, D

Lactation Risk Category: L2, L2

Adult Concerns: Hypothyroidism, liver toxicity, aplastic anemia, anemia.

Pediatric Concerns: None reported, but observed closely for thyroid function.

Drug Interactions: Activity of oral anticoagulants may be potentiated by PTU associated anti-vitamin K activity.

Relative Infant Dose Range: 1.8%

Adult Dose: 100 mg TID

Alternatives:

T½ = 1.5-5 hours M/P = 0.1
PHL = PB = 80-95%
Tmax = 1 hours Oral = 50-95%
MW = 170 pKa = 12.89
Vd = 0.87
References
1. Cooper DS. Antithyroid drugs: to breast-feed or not to breast-feed. Am J Obstet Gynecol 1987; 157(2):234-235.
2. Kampmann JP, Johansen K, Hansen JM, Helweg J. Propylthiouracil in human milk. Revision of a dogma. Lancet 1980; 1(8171):736-737.

[Rach74]

#1171565

Thanks so much for posting this info Alexis.

Do you have your baby’s thyroid levels monitored?

The doctor said on a higher dose of medication that my baby would have to be checked. She had a couple of blood tests after birth which weren’t much fun – poor thing screamed her head off and then collapsed into a deep sleep. She tested positive for neonatal graves (despite my levels being normal all through pregnancy and before), but fortunately it resolved on its own by the second blood test without any noticable symptoms ever occurring.

Rachael

[adenure]

#1171566

Hi!

Yes, I had his blood drawn when I started the meds. (6 weeks ago) to establish a baseline (which was normal). The recommended testing is every 3 mo. I think. Although on 5 mg., he should be fine. Yeah, poor guy was napping in my arms when they stuck the needle in his arm to draw blood 😮 Ouch! He cried, but was fine after it was done. For me, breastfeeding is very important. I wasn’t able to nurse my 1st son and he has asthma and anaphylaxis to peanuts (anaphylactic allergies to food and medicine runs in my family). I nursed my 2nd son for 2 years & my 3rd son for 3 years and neither of them have any allergies or asthma. So, I’m committed to nursing my youngest as long as I possibly can. I’ve nursed him through 2 emergency room visits (my own) and through the worst part of my Graves when I was dealing with my worst hyper symptoms a few months ago. It hasn’t been easy, but I’m going to do my best to stick with it.

Alexis

[Rach74]

#1171567

Every 3 months is really not too bad, I was thinking it would be more often than that. I am also keen to keep breastfeeding as I think it would currently be more traumatic for my baby to stop breastfeeding than to get occasional blood tests. She is not the least bit interested in the bottle – even if it contains expressed milk!

Rachael

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