Levothyroxine Injection

What is this medication?

LEVOTHYROXINE (lee voe thye ROX een) treats low thyroid levels (hypothyroidism). It works by replacing a thyroid hormone normally made by the body. Thyroid hormones play an important role in your overall health. They help support metabolism and energy levels.

This medicine may be used for other purposes; ask your health care provider or pharmacist if you have questions.

COMMON BRAND NAME(S): Synthroid

What should I tell my care team before I take this medication?

They need to know if you have any of these conditions:

• Addison disease
• Adrenal gland problem
• Bone problems
• Chest pain
• Diabetes
• Dieting or on a weight loss program
• Fertility problems
• Heart disease
• Pituitary gland problem
• Take medications that treat or prevent blood clots
• An unusual or allergic reaction to levothyroxine, other medications, foods, dyes, or preservatives
• Pregnant or trying to get pregnant
• Breastfeeding

How should I use this medication?

This medication is for injection into a muscle or into a vein. It is given in a hospital or clinic.

Contact your care team regarding the use of this medication in children. While this medication may be prescribed for children and infants as young as a few days of age for selected conditions, precautions do apply.

Overdosage: If you think you have taken too much of this medicine contact a poison control center or emergency room at once.

NOTE: This medicine is only for you. Do not share this medicine with others.

What if I miss a dose?

This does not apply.

What may interact with this medication?

• Amiodarone
• Carbamazepine
• Certain medications for depression
• Certain medications to treat cancer
• Clofibrate
• Digoxin
• Estrogen or progestin hormones
• Ketamine
• Lithium
• Medications for colds and breathing difficulties
• Medications for diabetes
• Medications or dietary supplements for weight loss
• Methadone
• Oxandrolone
• Phenobarbital or other barbiturates
• Phenytoin
• Rifampin
• Soy isoflavones
• Steroid medications, such as prednisone or cortisone
• Testosterone
• Theophylline
• Warfarin

This list may not describe all possible interactions. Give your health care provider a list of all the medicines, herbs, non-prescription drugs, or dietary supplements you use. Also tell them if you smoke, drink alcohol, or use illegal drugs. Some items may interact with your medicine.

What should I watch for while using this medication?

Visit your care team for regular checks on your progress. Tell your care team if your symptoms do not start to get better or if they get worse. It may be some time before you see the benefit from this medication.

Do not switch brands of this medication unless your care team agrees with the change. Ask questions if you are uncertain.

You may need blood work done while you are taking this medication.

Biotin (vitamin B7) may interfere with your thyroid function test. Stop taking supplements that contain biotin 2 days before your blood work.

This medication can affect blood sugar levels. If you have diabetes, check your blood sugar as directed.

What side effects may I notice from receiving this medication?

Side effects that you should report to your care team as soon as possible:

• Allergic reactions—skin rash, itching, hives, swelling of the face, lips, tongue, or throat
• Anxiety, nervousness
• Excessive sweating or sensitivity to heat
• Fever
• Heart palpitations—rapid, pounding, or irregular heartbeat
• Heart rhythm changes—fast or irregular heartbeat, dizziness, feeling faint or lightheaded, chest pain, trouble breathing
• Irregular menstrual cycles or spotting
• Severe diarrhea
• Tremors or shaking
• Trouble sleeping

Side effects that usually do not require medical attention (report to your care team if they continue or are bothersome):

• Changes in appetite
• Hair loss
• Headache
• Nausea
• Weight loss

This list may not describe all possible side effects. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Where should I keep my medication?

This does not apply. This medication will be given to you in a hospital or clinic. You will not store this medication at home.

NOTE: This sheet is a summary. It may not cover all possible information. If you have questions about this medicine, talk to your doctor, pharmacist, or health care provider.