Novothyral

Novothyral is a combination product that contains both thyroid hormones: levothyroxine (T4) and liothyronine (T3). It is used to treat an underactive thyroid (hypothyroidism).

Most patients do well on T4 alone (L-thyroxine), because the body converts T4 into the more active T3. However, some patients report persistent symptoms such as fatigue or difficulty concentrating despite normal TSH levels. In these cases, combination therapy with T3 may be considered.

Novothyral is manufactured by Merck. Prescribing it requires careful medical consideration.

The product contains two thyroid hormones.

Levothyroxine (T4) is the synthetically produced form of the hormone that the thyroid gland mainly makes. It acts as a storage form: the body converts it into active T3 as needed. This results in a steady level.

Liothyronine (T3) is already the active form. It acts faster, but also for a shorter time.

The combination is approved for the treatment of an underactive thyroid. In practice, it is mainly considered when symptoms persist on levothyroxine alone even though blood test results are normal. Whether this applies in an individual case is decided by the medical review based on the blood test results.

Because the T3 component takes effect more rapidly, the body reacts more sensitively to dose changes than with a product containing T4 only. Even small deviations can trigger palpitations, restlessness, or sleep problems.

Novothyral may be suitable for:

• Patients with hypothyroidism who continue to have symptoms on T4 alone
• After careful medical consideration
• In cases of proven impaired T4-to-T3 conversion

Standard therapy remains L-thyroxine alone. Combination therapy is not suitable for all patients and is not generally recommended by medical societies.

Special caution and medical clarification in cases of:

• Coronary heart disease, heart failure, or heart rhythm disorders with a fast pulse (even a mild overactive thyroid caused by the medicine must be strictly avoided, and thyroid levels are checked more often)
• Older patients (start with a low dose, slow increase, more levothyroxine and less liothyronine than usual)
• Women after menopause with an increased risk of osteoporosis (close monitoring of thyroid levels)

Available strengths:

• Novothyral 75: 75 mcg T4 + 15 mcg T3
• Novothyral 100: 100 mcg T4 + 20 mcg T3

Dosage:

• Individualized based on TSH, fT3, and fT4
• Start with the lowest dose
• Close laboratory monitoring required
• Switching from L-thyroxine to Novothyral only under medical supervision

• Once daily in the morning, on an empty stomach, at least half an hour before breakfast, with a little water.
• The interval before the meal is important: food, especially coffee, milk, and soy products, reduces absorption.
• The dose is set by the doctor and increased slowly — with particular caution in older people and in people with heart disease.
• Do not increase or stop on your own. Even if nothing seems to change: the effect builds up over weeks.

Intervals from other medicines

• At least two hours apart from products containing calcium, magnesium, or iron, and from medicines for heartburn.
• At least four to five hours apart from colestyramine and similar medicines.

Missed dose: If you notice it on the same morning, you can still take the tablet. Otherwise, continue as normal the next day — do not take a double dose.

Monitoring: After every dose change and after switching products, blood levels should be checked, usually after six to eight weeks.

Do not use in cases of:

• Hypersensitivity to any of the ingredients.
• Untreated overactive thyroid.
• Untreated adrenocortical insufficiency.
• Untreated dysfunction of the pituitary gland with adrenal involvement.
• Recent heart attack, acute inflammation of the heart muscle, acute inflammation of all layers of the heart wall.

To be clarified with a doctor before use: Coronary heart disease, heart failure, heart rhythm disorders, high blood pressure, severe or long-standing underactive thyroid, and older age. In these cases, the dose is adjusted particularly slowly.

Not for weight loss. Thyroid hormones are not suitable for this; in people with normal thyroid function, higher doses can cause serious, even life-threatening side effects.

When the dose is set correctly, side effects are rare. If they do occur, they are usually signs of a dose that is too high — the body then reacts as it would with an overactive thyroid:

• Palpitations, fast or irregular pulse
• Inner restlessness, nervousness, tremor
• Sleep problems
• Increased sweating, heat sensitivity
• Weight loss despite unchanged eating habits
• Diarrhea
• Headache, muscle weakness, muscle cramps
• In women: menstrual cycle disorders

Such signs should be checked by a doctor; usually a dose adjustment is enough.

Rare: Hypersensitivity reactions of the skin. With prolonged use of higher doses, bone density may decrease.

Have it checked by a doctor immediately in case of: persistent racing heart, heart rhythm disorders, chest pain, or shortness of breath.

The effect may be weakened by:

• Products containing calcium, magnesium, or iron, and medicines for heartburn (keep the interval)
• Colestyramine, colestipol, sevelamer
• Certain medicines for epilepsy (carbamazepine, phenytoin), rifampicin
• Soy-containing foods and dietary supplements

The effect of other medicines may change:

• Coumarin-type blood thinners: The tendency to bleed may increase; clotting values should be monitored.
• Blood sugar-lowering medicines and insulin: The requirement may change; blood sugar should be monitored more closely.
• Cardiac glycosides: The effect may decrease.

Other: Amiodarone, iodine-containing contrast agents, and lithium affect thyroid function. Estrogen-containing products can increase the requirement.

Please list all medicines you take, including non-prescription ones.