Peri-Operative Considerations When HALYCIL is administered pre-operatively, iodine, in the form of a strong iodine solution (Lugol’s solution or potassium iodide solution) should be given concomitantly for 7 -10 days prior to surgery.
The rationale for this is to reduce the vascularity and fragility of the thyroid gland. Renal HALYCIL should be used with caution in patients with renal impairment. 1 Pregnant Women Fertility Hyperthyroidism can cause a marked reduction in sperm count resulting in infertility.
Treatment with HALYCIL may result in normalisation in sperm count once the thyroid function is controlled. Hyperthyroidism can cause a reduction in fertility. Treatment with HALYCIL can result in rapid normalisation in fertility once the thyroid function is controlled.
Women of childbearing potential should use effective methods of contraception during HALYCIL therapy and should be informed about the potential risks of HALYCIL use during pregnancy. 1 Pregnant Women below. Respiratory In view of the fact that hypothyroid patients seem to have poor adrenergic nervous function, HALYCIL should be used with caution in patients with asthma.
Skin HALYCIL should be discontinued immediately at the appearance of a skin rash, as the rash may be, in some instances, followed by dermatological reactions/hypersensitivity syndrome . 1 Pregnant Women Hyperthyroidism in pregnant women should be adequately treated to prevent serious maternal and fetal complications.
Individual benefit/risk assessment is necessary before treatment with HALYCIL during pregnancy. If HALYCIL is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be warned of the potential hazard to the moth er and fetus of liver damage.
HALYCIL can be used prior to conception and in the first trimester of pregnancy where clinically appropriate due to the higher risk of congenital abnormalities with methimazole during fetal organogenesis in the first trimester. After the first trimester of pregnancy, the use of an alternative antithyroid medication may be advisable given the potential for maternal hepatotoxicity from HALYCIL.
HALYCIL should be administered during pregnancy at the lowest effective dose without additional administration of thyroid hormones. Close maternal, fetal and neonatal monitoring is recommended, with adjustment of HALYCIL as necessary.
HALYCIL, used judiciously, is an effective drug for the treatment of hyperthyroidism in pregnant women. However, the drug readily crosses the placental barrier where it can induce goiter and hypothyroidism in the developing fetus. Rare cases of congenital anomalies have been observed post-marketing.
5 Post-Market Adverse Reactions Product Monograph Master Template Template date: September 2020 HALYCIL™ (propylthiouracil) Page 10 of 22 Epidemiological studies provide conflicting results regarding the risk of congenital malformations.
2 Breast-feeding HALYCIL is excreted in breast milk and is contraindicated in nursing mothers. 3 Pediatrics Pediatrics (<18 years of age): No data are available to Health Canada; therefore, Health Canada has not authorized an indication for pediatric use.
4 Geriatrics Geriatrics (>65 years of age): Evidence from clinical studies and experience suggests that use in the geriatric population is associated with no differences in safety or effectiveness. 1 Adverse Reaction Overview The most serious adverse reactions associated with HALYCIL are agranulocytosis, hepatotoxicity and rarely, systemic vasculitis.
Recovery is often possible following immediate cessation of the drug. Inhibition of hemopoiesis (agranulocytosis, granulocytopenia, leucopenia, thrombocytopenia) is the most serious side effect. 5%. It usually develops in the first few months of therapy, is dose-related and is reversible on rapid withdrawal of the drug.
Severe adverse reactions include liver injury presenting as hepatitis, liver failure necessitating liver transplantation or resulting in death. See 7 WARNINGS AND PRECAUTIONS Hepatocellular necrosis and fulminant hepatic failure have been reported in patients treated with HALYCIL.
Typically, these reactions occur within the first two months of HALYCIL treatment. Injury is reversible upon discontinuation of HALYCIL although encephalopathy and/or substantial hepatic necrosis have been reported. 2% in patients treated with HALYCIL.
HALYCIL-induced hepatotoxicity is not dose-related and is thought to be idiosyncratic with an autoimmune component.
Blood and Lymphatic System:
Reversible leucopenia, agranulocytosis, thrombocytopenia, leucopenia aplastic anemia, pancytopenia; a rare complication of therapy is a tendency to hemorrhage associate with hypoprothrombinemia which may be controlled by the administration of vitamin K1.
Ear and Labyrinth Disorders:
Hearing impairment may occur with HALYCIL. The impairment usually becomes less marked after withdrawal of the drug.
Gastrointestinal Disorders:
Nausea, gastrointestinal disturbances, taste perversion, rarely vomiting.
General Disorders and Administration Site Conditions:
Fever.
Product Monograph Master Template Template date:
September 2020 HALYCIL™ (propylthiouracil) Page 11 of 22 Hepatic Function: Jaundice (usually cholestatic), hepatic necrosis (sometimes with fatal consequences), encephalopathy, asymptomatic liver function test abnormalities (increased serum bilirubin, alanine transaminase and/or alkaline phosphatase concentrations), which are reversible on dose reduction or […]