Drug reference

Levothyroxine sodium

BNF 80 (2020–2021)

Source: BNF 80 (2020–2021)
PDF pages: 838, 839

Review source pages for extracted sections and age labels. BNF dose snippets show only their first line.

Overview

Indications And Dose

Hypothyroidism ▶BY MOUTH ▶Adult 18–49 years: Initially 50–100 micrograms once daily; adjusted in steps of 25–50 micrograms every 3–4 weeks, adjusted according to response; maintenance 100–200 micrograms once daily, dose to be taken preferably at least 30 minutes before breakfast, caffeine-containing liquids (e.g. coffee, tea), or other medication ▶Adult 50 years and over: Initially 25 micrograms once daily; adjusted in steps of 25 micrograms every 4 weeks, adjusted according to response; maintenance 50–200 micrograms once daily, dose to be taken preferably at least 30 minutes before breakfast, caffeine-containing liquids (e.g. coffee, tea), or other medication Hypothyroidism in patients with cardiac disease | Severe hypothyroidism ▶BY MOUTH ▶Adult: Initially 25 micrograms once daily; adjusted in steps of 25 micrograms every 4 weeks, adjusted according to response; maintenance 50–200 micrograms once daily, dose to be taken preferably at least 30 minutes before breakfast, caffeine-containing liquids (e.g. coffee, tea), or other medication Hyperthyroidism (blocking-replacement regimen) in combination with carbimazole ▶BY MOUTH ▶Adult: 50–150 micrograms daily therapy usually given for 18 months

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Contra Indications

Thyrotoxicosis

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Cautions

Cardiovascular disorders. diabetes insipidus. diabetes mellitus (dose of antidiabetic drugs including insulin may need to be increased). elderly. hypertension. long-standing hypothyroidism. myocardial infarction. myocardial insufﬁciency. panhypopituitarism (initiate corticosteroid therapy before starting levothyroxine). predisposition to adrenal insufﬁciency (initiate corticosteroid therapy before starting levothyroxine) CAUTIONS, FURTHER INFORMATION ▶Cardiovascular disorders Baseline ECG is valuable because changes induced by hypothyroidism can be confused with ischaemia.

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Safety

Interactions

→Appendix 1: thyroid hormones

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Side Effects

Angina pectoris. anxiety. arrhythmias. arthralgia. diarrhoea. dyspnoea. fever. ﬂushing. headache. hyperhidrosis. insomnia. malaise. menstruation irregular. muscle spasms. muscle weakness . oedema. palpitations. skin reactions. thyrotoxic crisis. tremor. vomiting. weight decreased SIDE-EFFECTS, FURTHER INFORMATION Initial dosage in patients with cardiovascular disorders If metabolism increases too rapidly (causing diarrhoea, nervousness, rapid pulse, insomnia, tremors and sometimes anginal pain where there is latent myocardial ischaemia), reduce dose or withhold for 1–2 days and start again at a lower dose.

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Pregnancy

Levothyroxine may cross the placenta. Excessive or insufﬁcient maternal thyroid hormones can be detrimental to fetus. Dose adjustments Levothyroxine requirement may increase during pregnancy. Monitoring Assess maternal thyroid function before conception (if possible), at diagnosis of pregnancy, at antenatal booking, during both the second and third trimesters, and after delivery (more frequent monitoring required on initiation or adjustment of levothyroxine).

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Breast Feeding

Amount too small to affect tests for neonatal hypothyroidism.

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Dose and formulations

Medicinal Forms

There can be variation in the licensing of different medicines containing the same drug. Forms available from special-order manufacturers include: capsule, oral suspension, oral solution Tablet ▶Levothyroxine sodium (Non-proprietary) Levothyroxine sodium anhydrous 12.5 microgram Levothyroxine sodium 12.5microgram tablets | 28 tablet P £12.49 DT = £8.19 Levothyroxine sodium anhydrous 25 microgram Levothyroxine sodium 25microgram tablets | 28 tablet P £3.05 DT = £1.50 | 500 tablet P £41.61–£54.46 Levothyroxine sodium 25microgram tablets lactose free | 100 tablet P s Levothyroxine sodium anhydrous 50 microgram Levothyroxine sodium 50microgram tablets lactose free | 100 tablet P s Levothyroxine sodium 50microgram tablets | 28 tablet P £1.50 DT = £1.19 | 1000 tablet P £42.50–£55.71 Levothyroxine sodium anhydrous 75 microgram Levothyroxine sodium 75microgram tablets | 28 tablet P £4.00 DT = £3.07 Levothyroxine sodium anhydrous 100 microgram Levothyroxine sodium 100microgram tablets lactose free | 100 tablet P s Levothyroxine sodium 100microgram tablets | 28 tablet P £1.77 DT = £1.19 | 1000 tablet P £42.50–£56.07 ▶Eltroxin (Advanz Pharma) Levothyroxine sodium anhydrous 25 microgram Eltroxin 25microgram tablets | 28 tablet P £2.54 DT = £1.50 Levothyroxine sodium anhydrous 50 microgram Eltroxin 50microgram tablets | 28 tablet P £1.77 DT = £1.19 Levothyroxine sodium anhydrous 100 microgram Eltroxin 100microgram tablets | 28 tablet P £1.78 DT = £1.19 Oral solution ▶Levothyroxine sodium (Non-proprietary) Levothyroxine sodium anhydrous 5 microgram per 1 ml Levothyroxine sodium 25micrograms/5ml oral solution sugar- free | 100 ml P £118.63 DT = £94.99 Levothyroxine sodium anhydrous 10 microgram per 1 ml Levothyroxine sodium 50micrograms/5ml oral solution sugar- free | 100 ml P £107.93 DT = £96.57 Levothyroxine sodium anhydrous 20 microgram per 1 ml Levothyroxine sodium 100micrograms/5ml oral solution sugar- free | 100 ml P £165.00 DT = £164.99 Levothyroxine sodium anhydrous 25 microgram per 1 ml Levothyroxine sodium 125micrograms/5ml oral solution sugar- free | 100 ml P £185.00 DT = £185.00 Capsule ▶Tirosint (Imported (United States)) Levothyroxine sodium anhydrous 25 microgram Tirosint 25microgram capsules | 28 capsule P s Levothyroxine sodium anhydrous 50 microgram Tirosint 50microgram capsules | 28 capsule P s Levothyroxine sodium anhydrous 100 microgram Tirosint 100microgram capsules | 28 capsule P s

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Dose text by age group

Adult 18–49 years

Initially 50–100 micrograms once

First-line fragment. Read the complete Indications and Dose section above.

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Adult 50 years and over

Initially 25 micrograms once

First-line fragment. Read the complete Indications and Dose section above.

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Adult

Initially 25 micrograms once daily; adjusted in

First-line fragment. Read the complete Indications and Dose section above.

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Adult

50–150 micrograms daily therapy usually given

First-line fragment. Read the complete Indications and Dose section above.

PDF page 838

Age labels are extracted for navigation. Check the complete source section and current local guidance before clinical use.

Drug reference

Levothyroxine sodium

BNF 80 (2020–2021)

Source: BNF 80 (2020–2021)
PDF pages: 838, 839

Review source pages for extracted sections and age labels. BNF dose snippets show only their first line.

Overview

Indications And Dose

PDF page 838

Contra Indications

Thyrotoxicosis

PDF page 838

Cautions

PDF page 838

Safety

Interactions

→Appendix 1: thyroid hormones

PDF page 838

Side Effects

PDF page 838

Pregnancy

PDF page 838

Breast Feeding

Amount too small to affect tests for neonatal hypothyroidism.

PDF page 838

Dose and formulations

Medicinal Forms

PDF pages 838, 839

Dose text by age group

Adult 18–49 years

Initially 50–100 micrograms once

First-line fragment. Read the complete Indications and Dose section above.

PDF page 838

Adult 50 years and over

Initially 25 micrograms once

First-line fragment. Read the complete Indications and Dose section above.

PDF page 838

Adult

Initially 25 micrograms once daily; adjusted in

First-line fragment. Read the complete Indications and Dose section above.

PDF page 838

Adult

50–150 micrograms daily therapy usually given

First-line fragment. Read the complete Indications and Dose section above.

PDF page 838

Age labels are extracted for navigation. Check the complete source section and current local guidance before clinical use.