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's disease or other adrenal gland problem
• Angina
• Bone problems
• Dieting or on a weight loss program
• Fertility problems
• Heart disease
• High blood sugar (diabetes)
• Pituitary gland problem
• Take medications that treat or prevent blood clots
• An unusual or allergic reaction to levothyroxine, thyroid hormones, other medications, foods, dyes, or preservatives
• Pregnant or trying to get pregnant
• Breast-feeding

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
• Female hormones, like estrogens and birth control pills, patches, rings, or injections
• 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 like 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?

You will need regular exams and occasional blood tests to check the response to treatment. If you are receiving this medication for an underactive thyroid, it may be several weeks before you notice an improvement. Check with your care team if your symptoms do not improve.

It may be necessary for you to take this medication for the rest of your life. Do not stop using this medication unless your care team advises you to.

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

You may lose some of your hair when you first start treatment. With time, this usually corrects itself.

If you are going to have surgery, tell your care team that you are taking this medication.

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.