Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes Cytomel (Liothyronine). If you are concerned about side effects, discuss the risks and benefits of Cytomel (Liothyronine) with your doctor.

The following side effects have been reported by at least 1% of people taking Cytomel (Liothyronine). Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• headache

Although most of these side effects listed below don't happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• confusion
• Diarrhea
• dizziness
• fast or irregular heartbeat
• fatigue
• Fever
• increased appetite
• menstrual changes
• sweating
• signs of an allergic skin reaction (e.g., rash, itchiness)
• trouble sleeping
• weight loss

Stop taking the medication and seek immediate medical attention if any of the following occur:

• chest pain
• signs of a heart attack (e.g., chest pain, anxiety, pressure or squeezing sensation in the chest, paleness, shortness of breath, pain spreading to shoulders, neck, jaw)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking Cytomel (Liothyronine).

5 µg
Each round, flat-faced, bevelled-edged, compressed white-to-off-white tablet, embossed with "KPI" on one side and "115" on the other side, contains Cytomel (Liothyronine) sodium equivalent to Cytomel (Liothyronine) 5 µg. Nonmedicinal ingredients: calcium sulfate, gelatin, starch, stearic acid, sucrose, and talc.

25 µg
Each round, flat-faced, bevelled-edged, compressed white-to-off-white tablet, embossed with "KPI116" on one side and scored on the other side, contains Cytomel (Liothyronine) sodium equivalent to Cytomel (Liothyronine) 25 µg. Nonmedicinal ingredients: calcium sulfate, gelatin, starch, stearic acid, sucrose, and talc.

Do not take Cytomel (Liothyronine) if you:

• are allergic to Cytomel (Liothyronine) or any ingredients of the medication
• have certain uncorrected problems of the adrenal glands
• have recently had a Heart Attack

There may be an interaction between Cytomel (Liothyronine) and any of the following:

• Amiodarone
• amphetamines (e.g., Dextroamphetamine)
• antacids that contain aluminum or calcium
• antidiabetes medications (e.g., insulin, Glyburide, Metformin)
• birth control pills
• calcium polystyrene
• calcium supplements (e.g., calcium carbonate, calcium citrate)
• Carbamazepine
• Cholestyramine
• ciprofloxacin
• Colesevelam
• Colestipol
• diet pills
• Digoxin
• estrogens (e.g., conjugated estrogen, Estradiol, ethinyl estradiol)
• iron supplements (e.g., ferrous fumarate, ferrous sulphate)
• Methadone
• Phenytoin
• rifampin
• ritonavir
• simethicone
• sodium iodide I131
• sodium polystyrene
• sympathomimetic medications (e.g., Epinephrine, norepinephrine)
• selective serotonin reuptake inhibitors (SSRIs; e.g., Citalopram, Fluoxetine, Paroxetine, Sertraline)
• Tamoxifen
• theophyllines (e.g., Aminophylline, Oxtriphylline, Theophylline)
• tricyclic antidepressants (e.g., Amitriptyline, Imipramine)
• Warfarin

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with Cytomel (Liothyronine). Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications that you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the Nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or Allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use Cytomel (Liothyronine).

Bone density: Long term use of thyroid mediations can cause bones to lose thickness. If you have an increased risk for Osteoporosis (bone thinning) or are taking medications that reduce bone thickness (e.g., Prednisone or antiseizure medications), before you start taking Cytomel (Liothyronine), discuss with your doctor how Cytomel (Liothyronine) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Cytomel (Liothyronine), and whether any special monitoring is needed.

Diabetes: Cytomel (Liothyronine) may cause blood sugar to increase and glucose tolerance may change. People with diabetes may find it necessary to monitor their blood sugar more frequently while using Cytomel (Liothyronine).

If you have diabetes or are at risk for developing diabetes, discuss with your doctor how Cytomel (Liothyronine) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Cytomel (Liothyronine), and whether any special monitoring is needed.

Heart disease: Starting Cytomel (Liothyronine) may cause the heart to work harder than it has been used to. This can cause symptoms of Angina or other heart disease to worsen. If you have angina or other heart disease, discuss with your doctor how Cytomel (Liothyronine) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Cytomel (Liothyronine), and whether any special monitoring is needed.

Pregnancy: Cytomel (Liothyronine) does not cross the placenta, therefore it does not directly affect the development of an unborn baby. During pregnancy, your doctor will probably want to do blood tests to make sure the level of thyroid in the blood stream is appropriate. Cytomel (Liothyronine) is safe to use during pregnancy.

Breast-feeding: Cytomel (Liothyronine) passes into breast milk in small amounts. It is important to continue taking thyroid hormone even when you are breast-feeding. Inform your doctor if you are breast-feeding or intending to breast-feed while taking Cytomel (Liothyronine).

Seniors: Older people may be more sensitive to the effects of Cytomel (Liothyronine) and should be watchful for side effects, particularly those involving the heart.