Is levothyroxine enough for everybody with hypothyroidism?

About 10 to 15% pts on levothyroxine end up still with symptoms of hypothyroidism while taking the medication.

This is because of unmet biological need for T3.

Looking into history,

In 1965, 85% of thyroid prescriptions were for natural thyroid products.

Then came Johnny come lately,Levothyroxine and it was felt there was peripheral conversion of T4 to T3.

T4 replacement suppressed TSH and normalized T4 and T3 levels but at the expense of elevated T4 to T3 ratio.

Other markers for bonfire thyroxine replacement did not suggest correction of lipids,or signs of hypothyroidism.

With elevated T4 to T3 ratio impairs systemic T3 ptoduction by down regulating deiodinase pathway.

With only T4 replacement only,T3 levels do not come to hypothyroid state.

A specific gene in some hypothyroid patientsDIO2, a type 2 iodothronine deiodinase gene improves hypothyroid symptoms with replacement of T 4 And T3.

Dr Gregory W Rutecki M.D at Cleveland clinic wrote this paper.

Grapefruit juice and statins

Grapefruit contains a group of compounds called furanocoumarins.

Once we drink juice,the CYP3A4enzymes start working breaking down the chemicals.

Medications that are broken down by CYP3A4 are Simvastatin,atorvastatin,viagra,cialis,Levitras,coumadin( warfarin),codeine.

Drinking orange juice or water does not affect this enzyme.

A genetic test can be done to see if CYP3A4 is working slow or fast in you.

If the grapefruit juice and the medications listed above are taken at different times atleast 8 to 10 hours apart then it does not matter.

If there are more concerns of medication toxicity with grapefruit juice then reduce the medication dose by half or even you can skip a day of medication.

Grapefruit juice and statins

Many a times a bottle of prescription drugs state"do not eat grapefruit or drink juice when taking this medicine".

The enzyme important in breakdown of a chemical in grapefruit juice is also involved in breakdown of certain drugs.

The molecule called cyP3A4 resides in liver,colon,small intestine.

Thus if cyP3A4 enzymes are preoccupied in breakdown of grapefruit juice you just drank,there will not be enzymes available to breakdown medications.

In 1989,a group of Canadian scientists were studying interactions of ethanol on felodipine taken for high bp.The scientists used grapefruit juice to disguise taste of ethanol and observed differences 

regarding amount of drug in blood stream.It was five times mor in blood stream of people who drank medicine with grapefruit juice compared to when it was taken with water.