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Thyroid drugs available in New Zealand

Datasheets

Funded – levothyroxine (T4) - for treatment of hypothyroidism

• Synthroid (Abbott Laboratories)
• Levothyroxine (Goldshield)
• Eltroxin (new formulation) (GlaxoSmithKline)

With respect to Eltroxin, please see our comments under 'Side effects' below.

Approved but not funded – levothyroxine (T4) - for treatment of hypothyroidism

• Eutroxsig

Not approved or funded – levothyroxine (T4) - for treatment of hypothyroidism

• Eltroxin (original formulation) (Aspen, previously GlaxoSmithKline)

This is the original Eltroxin from Canada that used to be funded in New Zealand until mid 2007. It is still being made in Canada and can be ordered online at www.canadadrugs.com (prices are in US dollars). You need a prescription to be able to order and import this medicine. The prescription cannot be for more than 3 months worth of medicine.

More information about obtaining prescription medicines over the internet can be found under 'Prescriber Update Articles' below.

Link to important information on manufacturer changes

• Almus

According to the manufacturer of Almus, it contains the same ingredients as Actavis. Almus appears to be the only available levothyroxine that does not contain acacia. This ingredient can cause asthma in some patients.

Not approved or funded - liothyronine (T3) - for additional or alternative treatment of hypothyroidism

• Goldshield Tertroxin

Not approved or funded – desiccated porcine thyroid extract - for treatment of hypothyroidism

• Nature-Throid

Available in New Zealand as 'Whole thyroid' from Pharmaceutical Compounding NZ LTD. Capsules can also be compounded.

Funded – carbimazole (antithyroid drug) - for treatment of hyperthyroidism

• Neo-Mercazole

Not funded – propylthiouracil (PTU) (antithyroid drug) - for treatment of hyperthyroidism

• Propylthiouracil

Side effects and drug interactions

Side effects

The possible side effects of (anti-)thyroid drugs are usually well described in the data sheets. We would, however, like to warn patients and their doctors that levothyroxine of the brand Eltroxin (new formulation, GlaxoSmithKline) has been reported to cause a much wider range of side effects than those currently included in the data sheet.

Although we acknowledge that there are patients who do not appear to suffer from side effects from this brand, many of our members have been very unwell after the change in formulation of Eltroxin in 2007. We do, for that reason, recommend reading The Eltroxin formulation change: An analysis of reports received by CARM, Dr M. Tatley, Director, New Zealand Pharmacovigilance Centre, 4 September 2008.

Reporting side effects

We recommend reporting side effects of drugs to the Centre for Adverse Reactions Monitoring (CARM) in Dunedin, either by a patient's doctor or by the patient her or himself. It is preferable to use CARM's reporting form, but it is also possible to send an e-mail to CARM as long as all the information required by the form is included in the e-mail. The required information includes:

• the start and stop dates for all medicines used (for non-suspect medicines where the dates are uncertain more general entries are acceptable, for example 'years')
• the brand name of the medicine(s), especially if the suspected reaction is associated with a change in medicines – mark the medicine suspected of causing the side effects and provide the batch numbers (printed on the label) where available
• the daily dose of the medicine(s) taken
• the reason why the medicine(s) is/are used
• the side effects experienced
• the date since when the side effects were experienced
• other medical conditions
• patient details (including sex and date of birth)
• doctor details

CARM finds this information extremely important to enable proper assessment of a report. CARM's address can be found on the form.

• CARM - Adverse Reactions Reporting Form
• e-mail CARM (carmnz@stonebow.otago.ac.nz)

Drug interactions

Taking too much anti-thyroid drugs such as carbimazole and propylthiouracil (prescribed to treat hyperthyroidism, see above) can cause symptoms of hypothyroidism, just like taking too much thyroid drugs such as levothyroxine or liothyronine (prescribed to treat hypothyroidism) can result in symptoms of hyperthyroidism (thyrotoxicosis).

Several other drugs can also interfere with your thyroid function or can affect the effectiveness of your (anti-)thyroid drugs. This includes both prescription drugs and over the counter drugs. Examples are:

• amiodarone (prescribed for treatment of cardiac rhythm disorders)
• lithium (brand name: Priadel) (anti-depressant prescribed to prevent and treat depression)
• interferon alpha (prescribed for treatment of, among other things, leukemia and viral infections such as Hepatitis B and C)
• interleukin-2 (used for the treatment of certain cancers)
• thalidomide (prescribed for the treatment of, among other things, multiple myeloma (a type of bone marrow cancer), Crohn's disease, rheumatoid arthritis and systemic lupus erythematosus)
• stavudine (brand name: Zerit) (used to treat patients infected with HIV)
• iodine containing supplements (including kelp, seaweed)
• iron supplements or multivitamins containing iron
• calcium supplements or multivitamins containing calcium
• antacids that contain aluminum or magnesium
• some ulcer medications, such as sucralfate (brand name: Carafate)
• some cholesterol-lowering drugs, such as cholestyramine (brand name: Questran Lite) and colestipol (brand name: Colestid)

If a patient is taking these drugs, it may sometimes be necessary to monitor the thyroid function or adjust the dosage of the thyroid medication. Patients are advised to keep their doctors informed of the drugs they are taking.

It is recommended to take antacids and calcium or iron containing drugs at a different time of the day (for example, at least four hours before or after taking thyroid medicines).

Other information relating to drugs prescribed for the treatment of thyroid conditions

Prescribing unapproved/non-funded medicines

• Unapproved Use of Medicines (Regulatory Issues, Medsafe)

In exceptional circumstances (strict conditions apply), it is possible to qualify for funding of medicines that have not been approved, or are not subsidised.

• Exceptional Circumstances FAQs (Pharmac)
• Exceptional circumstances form: Propylthiouracil (16 April 2008)

Prescriber Update Articles from Medsafe

• Prescription medicines obtained over the internet (August 2009)
• Use of unapproved medicines in New Zealand (August 2009)
• Electronic adverse reaction reports (August 2009)
• Launch of an electronic adverse reaction reporting tool (May 2009)
• Eltroxin update (February 2009)

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