Propylthiouracil Side Effects

Some side effects of propylthiouracil may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

For the Consumer

Applies to propylthiouracil: oral tablet

Get emergency medical help if you have any of these signs of an allergic reaction while taking propylthiouracil: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Stop taking propylthiouracil and call your doctor at once if you have a serious side effect such as:

• fever, sore throat, headache, body aches, flu symptoms;

• pale skin, easy bruising or bleeding (nosebleeds, bleeding gums), unusual weakness;

• dry cough, trouble breathing; or

• severe blistering, peeling, and red skin rash.

Propylthiouracil may also cause severe liver symptoms. Call your doctor at once if you have any of these liver symptoms:

• low fever, itching;

• nausea, stomach pain, loss of appetite;

• dark urine, clay-colored stools; or

• jaundice (yellowing of the skin or eyes).

Less serious side effects of propylthiouracil may include:

• upset stomach, vomiting;

• dizziness, spinning sensation;

• mild skin rash or itching;

• mild joint or muscle pain;

• decreased sense of taste; or

• hair loss.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.

For Healthcare Professionals

Applies to propylthiouracil: oral tablet

General

In general the overall incidence of side effects is relatively low (1% to 5%). Serious side effects may occur. These have included agranulocytosis, hepatitis, and vasculitis.

Hematologic

Hematologic side effects have included agranulocytosis (0.5%), granulocytopenia, and thrombocytopenia, as well as rare reports of aplastic anemia. Transient leukopenia is reported in up to 12% of patients, although this may occur in untreated hyperthyroid patients as well. Hypoprothrombinemia and bleeding have been reported.

Agranulocytosis occurs in approximately 0.5% of patients treated with propylthiouracil. Onset is typically within the first three months of therapy but isolated cases have occurred much later. Risk may be greater in patients over 40 years of age and in females.

Rare cases of aplastic anemia are also reported, although recovery in these cases is relatively high (73%).

Hepatic

Propylthiouracil-induced hepatotoxicity occurs rarely, although the exact incidence is unknown. Most cases present as hepatocellular hepatitis, with or without jaundice. Cholestatic jaundice is also reported. While many cases resolve with discontinuation of propylthiouracil therapy and supportive care, fatalities have occurred despite aggressive therapy.

While severe hepatotoxicity appears to be rare, transient and asymptomatic elevations in transaminases may occur in up to 28% of patients.

Hepatic side effects have included hepatocellular hepatitis with or without jaundice, cholestatic jaundice, hepatic encephalopathy, fulminant hepatic necrosis, splenomegaly, and elevations in liver function tests. Fatal hepatitis has been reported.

Dermatologic

Dermatologic side effects have included rash, urticaria, hair loss, and skin pigmentation. Exfoliative dermatitis and erythema nodosum have also been reported. Cases of cutaneous vasculitis resulting in death have been reported.

Erythema nodosum and fatal cases of cutaneous vasculitis are reported with propylthiouracil. In addition, purpuric rash, maculopapular rash, or bullous hemorrhagic lesions may occur in conjunction with other adverse effects of propylthiouracil such as hepatotoxicity or hematologic toxicity.

Immunologic

Immunologic side effects have included hepatic, hematologic, respiratory, and dermatologic effects. Vasculitis has been associated with propylthiouracil therapy as have positive ANA titers and a lupus-like syndrome.

Antineutrophil cytoplasmic antibodies against human neutrophil elastase as well as against proteinase 3 and/or myeloperoxidase were documented in six patients who developed vasculitis during propylthiouracil therapy for hyperthyroidism.

Clinical improvement and disappearance of or decline in antibodies were noted upon discontinuation of propylthiouracil in all six patients. Such antibodies were absent in seven other patients who did not develop vasculitis during propylthiouracil therapy for hyperthyroidism.

Respiratory

Respiratory side effects have included two cases of interstitial pneumonitis. Pulmonary infiltrates or alveolar hemorrhage have also been reported.

Manifestations of a vasculitic syndrome with the presence of anti-neutrophilic cytoplasmic antibodies (ANCA) have included alveolar hemorrhage or pulmonary infiltrates.

Nervous system

Nervous system side effects have included paresthesia, headache, drowsiness, neuritis, and vertigo.

Renal

Renal side effects have rarely included acute interstitial nephritis and renal failure.

Manifestations of a vasculitic syndrome with the presence of anti-neutrophilic cytoplasmic antibodies (ANCA) have included rapidly progressing glomerulonephritis (crescentic and pauci-immune necrotizing glomerulonephritis) sometimes leading to acute renal failure.

Cardiovascular

Cardiovascular side effects have included a case report of superior vena cava syndrome.

Gastrointestinal

Gastrointestinal side effects have included nausea, vomiting, epigastric distress, and taste disturbances.

Musculoskeletal

Musculoskeletal side effects have included arthralgia, myalgia, frank arthritis, and polymyositis.

Metabolic

Metabolic side effects have included a case report of severe hypocalcemia.

Other

Other side effects have included tinnitus, reversible sensorineural hearing loss, sialadenopathy, lymphadenopathy, and fever.

Reversible sensorineural hearing loss characterized by tinnitus and impaired hearing is reported in at least two cases. Fatigue, weight loss, and lupus-like syndrome accompanied the hearing loss in one case. In the other, migratory polyarthritis, fever, chills, and nonproductive cough were noted. Symptoms resolved after discontinuation of propylthiouracil.

Manifestations of a vasculitic syndrome with the presence of anti-neutrophilic cytoplasmic antibodies (ANCA) have included fever and leukocytoclastic vasculitis.

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