Levothyroxine - Informed Consent

INFORMED CONSENT FOR LEVOTHYROXINE (T4) THERAPY

§1 PURPOSE, CONTEXT, AND SCOPE

§1.1 This document constitutes an informed consent agreement between the Patient identified herein (the “Patient”) and the Prescribing Physician acting on behalf of the Clinic. It is intended to document that the Patient has received, understood, and accepted comprehensive information regarding the proposed pharmacological use of levothyroxine (synthetic thyroxine / T4).

§1.3 Health optimization context: The Patient understands that the Clinic operates as a proactive health optimization / longevity practice. The Clinic is not an emergency provider. The Patient is responsible for maintaining an appropriate relationship with a primary care physician and/or relevant specialist(s) for diagnosis and management of disease, acute care, and emergencies.

§1.4 This consent is governed by the laws of Denmark and the European Union, including but not limited to the Danish Health Act (Sundhedsloven) and Regulation (EU) 2016/679 (General Data Protection Regulation).

§1.5 By signing this document, the Patient confirms they have had adequate time to read, consider, and ask questions, and that their questions have been answered to their satisfaction.

§3 MEDICATION, CLASS, AND DESCRIPTION OF TREATMENT

§3.1 Levothyroxine is a synthetic form of thyroxine (T4), the primary hormone produced by the thyroid gland. The thyroid gland regulates metabolism, energy production, body temperature, heart rate, and numerous other physiological processes. Levothyroxine replaces or supplements the body’s own thyroid hormone production.

§3.3 Examples of levothyroxine products include (not exhaustive):

  • Eltroxin
  • Euthyrox
  • Levaxin
  • L-Thyroxin

§3.4 Intended use in this Clinic: The Patient understands that levothyroxine may be prescribed for:

  • On-label use: Treatment of diagnosed hypothyroidism (primary, secondary, post-surgical, or post-radioiodine), where TSH is elevated and/or free T4 is below the reference range.
  • Off-label / optimization use: Treatment of subclinical hypothyroidism (mildly elevated TSH with free T4 within the reference range) or thyroid optimization in the context of health optimization, where the Prescribing Physician judges that the Patient may benefit from thyroid hormone supplementation to improve symptoms, metabolic markers, or overall wellbeing.

§3.5 The Patient understands that when levothyroxine is prescribed for thyroid optimization in individuals with TSH values within the conventional reference range, this constitutes off-label use, and clinical outcomes cannot be guaranteed.

§3.6 The treatment will be administered orally, typically once daily on an empty stomach (at least 30–60 minutes before food), at a dose determined by the Prescribing Physician based on the Patient’s clinical status, body weight, age, cardiovascular risk, and laboratory results. Dosing is individualized and titrated gradually.

§4 REGULATORY STATUS AND APPROVED INDICATIONS

§4.1 Levothyroxine has been authorised by the European Medicines Agency (EMA) for the following indications:

  • Hypothyroidism (replacement therapy)
  • Thyroid-stimulating hormone (TSH) suppression in the management of thyroid cancer (post-surgical)
  • Goitre prophylaxis and treatment
  • Diagnostic use in thyroid suppression tests

§4.2 On-label use: When prescribed for diagnosed hypothyroidism (elevated TSH and/or low free T4 with clinical symptoms), levothyroxine use is within EMA-authorised indications.

§4.3 Off-label thyroid optimization: The Patient understands that prescribing levothyroxine primarily for “thyroid optimization,” subclinical hypothyroidism management in asymptomatic individuals, or proactive metabolic enhancement may be considered off-label depending on the Patient’s specific clinical circumstances. The Patient has been informed of this and accepts the information.

§4.4 The Patient understands that evidence supporting thyroid optimization in individuals with TSH values within the conventional reference range is limited and that benefits are not guaranteed.

§5 EXPECTED BENEFITS OF TREATMENT

§5.1 The Patient understands that the potential benefits of levothyroxine therapy may include, but are not limited to:

§5.1.1 Symptom improvement: Resolution or improvement of symptoms associated with thyroid hormone insufficiency, such as:

  • Fatigue, low energy, and reduced stamina
  • Weight gain or difficulty losing weight despite appropriate diet and exercise
  • Cold intolerance
  • Cognitive difficulties (“brain fog”), poor concentration, and memory impairment
  • Depressed mood, apathy, or irritability
  • Dry skin, hair loss, and brittle nails
  • Constipation
  • Muscle weakness, stiffness, or joint pain
  • Menstrual irregularities (in women)

§5.1.2 Metabolic marker improvements: Potential improvements in cholesterol levels (particularly LDL), triglycerides, and markers of metabolic efficiency in some individuals.

§5.1.3 Cardiovascular risk reduction: Untreated hypothyroidism is associated with increased cardiovascular risk. Appropriate levothyroxine replacement may reduce this risk.

§5.1.4 Quality of life: Improvement in overall energy, cognitive function, mood, and physical capacity where these were impaired by thyroid hormone insufficiency.

§5.2 No guarantee of benefit: The Patient acknowledges that benefits are variable and not guaranteed. Individual responses to levothyroxine vary. Some patients, particularly those with subclinical hypothyroidism or TSH values within the reference range, may not experience noticeable improvement. The Patient understands that levothyroxine does not guarantee prevention of age-related decline or improvement in healthspan beyond addressing thyroid hormone insufficiency.

§6 MATERIAL RISKS, SIDE EFFECTS, AND WARNINGS

§6.1 The Patient understands that all medicines carry risks. The following risks are material and may be serious. This list is not exhaustive.

§6.2 Common / expected adverse effects (typically related to dose adjustment; often resolve with dose reduction):

  • Palpitations or awareness of heartbeat
  • Tremor (fine hand tremor)
  • Anxiety, nervousness, or restlessness
  • Insomnia or sleep disturbance
  • Increased sweating or heat intolerance
  • Transient headache
  • Unintended weight loss
  • Diarrhoea or increased bowel frequency
  • Temporary hair shedding (usually resolves within months)

§6.3 Important: Most of the above side effects indicate that the dose is too high (overreplacement / iatrogenic thyrotoxicosis) and typically resolve promptly with dose reduction. The Patient agrees to report these symptoms to the Clinic rather than self-adjusting the dose.

§6.4 Uncommon adverse effects:

  • Menstrual irregularities
  • Muscle cramps
  • Flushing

§6.5 Rare but serious adverse effects:

§6.5.1 Cardiac arrhythmias: Excessive thyroid hormone levels may cause or worsen arrhythmias, including atrial fibrillation. The Patient must seek urgent medical care for persistent palpitations, irregular heartbeat, chest pain, or shortness of breath.

§6.5.2 Angina and cardiac events: In patients with pre-existing coronary artery disease, levothyroxine may precipitate or worsen angina. The Patient must disclose any history of heart disease.

§6.5.3 Bone mineral density reduction: Long-term overreplacement (supraphysiological doses) may reduce bone mineral density, particularly in postmenopausal women, increasing fracture risk. This risk is minimised with appropriate dose titration and monitoring.

§6.5.4 Adrenal crisis (critical): In patients with undiagnosed or untreated adrenal insufficiency (Addison’s disease or secondary adrenal insufficiency), initiating levothyroxine without first treating the adrenal insufficiency can precipitate a life-threatening adrenal crisis. The Patient must disclose any history of adrenal problems, prolonged corticosteroid use, or pituitary disease.

§6.5.5 Allergic reactions: Rare allergic reactions (to the active substance or excipients such as lactose or dyes) can occur. The Patient must seek urgent care for swelling of face/tongue/throat, difficulty breathing, or widespread rash.

§7 CONTRAINDICATIONS AND PRECAUTIONS

§7.1 The Patient must disclose all relevant medical history including:

  • History of heart disease, angina, arrhythmias, or heart failure
  • History of adrenal insufficiency or prolonged corticosteroid use
  • Pituitary disease
  • Diabetes mellitus (thyroid hormone affects glucose metabolism)
  • Osteoporosis or risk factors for osteoporosis
  • Pregnancy or planned pregnancy

§7.2 Absolute contraindications:

  • Known hypersensitivity or allergy to levothyroxine or any excipients
  • Untreated thyrotoxicosis (hyperthyroidism)
  • Untreated adrenal insufficiency (must be treated with corticosteroids before initiating levothyroxine)
  • Acute myocardial infarction

§7.3 Relative contraindications and precautions:

  • Coronary artery disease or significant cardiovascular risk (requires cautious dose titration)
  • Elderly patients (lower starting doses required)
  • Long-standing hypothyroidism (requires gradual dose introduction)
  • Diabetes mellitus (may require adjustment of antidiabetic therapy)
  • History of seizures (rare threshold lowering in susceptible individuals)

§7.4 The Prescribing Physician may decline to prescribe or may discontinue therapy if safety concerns arise.

§8 DRUG INTERACTIONS

§8.1 The Patient has disclosed all current medications, including prescription drugs, over-the-counter medications, supplements, and herbal products. The following interactions are of clinical significance:

§8.2 Absorption-reducing substances (critical — must be separated by at least 4 hours):

  • Calcium supplements and calcium-containing antacids
  • Iron supplements
  • Proton pump inhibitors (PPIs, e.g., omeprazole, pantoprazole)
  • Aluminium-containing antacids
  • Bile acid sequestrants (e.g., cholestyramine, colestipol)
  • Sucralfate
  • Soy-based products (if consumed in large amounts near dosing time)

§8.3 Anticoagulants (warfarin and other vitamin K antagonists): Levothyroxine may enhance the anticoagulant effect. INR monitoring and dose adjustment of anticoagulant may be required.

§8.4 Antidiabetic medications (insulin and oral hypoglycaemics): Thyroid hormone increases glucose metabolism. Adjustment of antidiabetic therapy may be necessary when initiating or changing levothyroxine dose.

§8.5 Amiodarone: Contains large amounts of iodine and can affect thyroid function in complex ways. Close monitoring is required.

§8.6 Lithium: Can induce hypothyroidism. Concurrent use requires careful thyroid function monitoring.

§8.7 Oestrogen therapy (including oral contraceptives and HRT): May increase thyroxine-binding globulin (TBG), potentially requiring levothyroxine dose adjustment.

§8.8 Carbamazepine, phenytoin, rifampicin: May increase levothyroxine metabolism, potentially requiring dose increase.

§8.9 The Patient agrees to inform the Clinic before starting any new medication, supplement, or herbal product.

§9 MONITORING, FOLLOW-UP, AND SAFETY COMMUNICATION

§9.1 The Patient agrees to follow-up as advised, which may include monitoring of symptoms, blood pressure, heart rate, body weight, and laboratory markers.

§9.2 Baseline assessments (before starting levothyroxine):

  • TSH (thyroid-stimulating hormone)
  • Free T4 (free thyroxine)
  • Free T3 (free triiodothyronine)
  • Thyroid antibodies (anti-TPO, anti-Tg) if indicated
  • Cortisol or adrenal function assessment (to exclude adrenal insufficiency if clinically indicated)
  • Lipid profile
  • Heart rate and blood pressure
  • ECG (if cardiovascular risk factors present)

§9.3 Follow-up monitoring:

  • TSH and free T4 at 6–8 weeks after initiation or any dose change
  • Once stable, TSH and free T4 every 3–6 months (or as clinically indicated)
  • Free T3 as clinically indicated
  • Clinical assessment of symptoms, heart rate, and adverse effects at each visit
  • Bone density monitoring (if long-term therapy at higher doses or in at-risk patients)

§9.4 Dose titration: The Patient understands that:

  • Levothyroxine dosing is individualized and adjusted based on laboratory results and clinical response
  • Typical starting dose: 25–50 mcg daily (lower in elderly patients or those with cardiac disease)
  • Dose adjustments are made in increments of 12.5–25 mcg every 6–8 weeks
  • The goal is to achieve optimal thyroid hormone levels while avoiding overreplacement
  • The Patient agrees to follow dosing instructions and not to self-adjust the dose

§9.5 Administration instructions: The Patient agrees to:

  • Take levothyroxine on an empty stomach, at least 30–60 minutes before food, with water only
  • Take at the same time each day (typically first thing in the morning)
  • Separate from calcium, iron, and other absorption-interfering substances by at least 4 hours
  • Not switch between brands without consulting the Clinic (bioavailability may differ between formulations)

§9.6 The Patient agrees to promptly report adverse effects, including persistent palpitations, chest pain, tremor, significant weight loss, anxiety, or other concerning symptoms.

§10 ALTERNATIVES TO TREATMENT

§10.1 Alternatives may include:

  • Lifestyle interventions (nutrition, activity, sleep optimization, stress management)
  • Nutritional optimization (ensuring adequate iodine, selenium, zinc, and iron intake where deficient)
  • Monitoring without treatment (“watchful waiting”), particularly for subclinical hypothyroidism with mildly elevated TSH
  • Specialist endocrinology referral
  • No pharmacological treatment

§10.2 The Patient understands they may decline treatment or stop treatment at any time.

§12 LIMITATION OF LIABILITY / NO GUARANTEE

§12.1 The Patient understands that medicine is not an exact science and no outcomes can be guaranteed.

§12.2 The Patient understands that adverse effects may occur despite appropriate prescribing and monitoring.

§12.3 The Patient understands that individual responses to levothyroxine vary and that not all patients will experience the expected benefits.

§12.4 Nothing in this consent excludes liability that cannot be excluded under applicable Danish law.

§13 WITHDRAWAL OF CONSENT

§13.1 The Patient may withdraw consent at any time by contacting the Clinic. The Prescribing Physician will provide guidance on safe dose reduction or discontinuation where applicable.

§13.2 The Patient understands that abrupt discontinuation of levothyroxine may lead to return of hypothyroid symptoms. Gradual dose reduction may be recommended in some circumstances.

§14 DATA PROTECTION AND RECORDKEEPING

§14.1 The Patient’s personal data and health information will be processed in accordance with GDPR and applicable Danish law.

§14.2 This consent may be retained as part of the Patient’s medical record.

§15 ACKNOWLEDGMENTS AND DECLARATIONS

By consenting, the Patient confirms the following:

  • I have read this consent document in its entirety, or it has been read to me, and I understand its contents.
  • I understand the medication prescribed (levothyroxine / synthetic T4) and the purpose of thyroid hormone therapy.
  • I understand whether my prescription is for on-label hypothyroidism treatment, off-label thyroid optimization, or both, as explained by my clinician.
  • I understand that benefits are variable and not guaranteed, particularly in cases of subclinical hypothyroidism or thyroid optimization.
  • I understand the material risks, including overreplacement effects (palpitations, tremor, anxiety, insomnia), cardiac arrhythmia risk, bone density effects with long-term supraphysiological dosing, and the critical importance of excluding adrenal insufficiency before treatment.
  • I understand the importance of correct administration (empty stomach, separated from calcium/iron/PPIs) and consistent daily dosing.
  • I understand that regular monitoring (TSH, free T4, free T3) is required, particularly after dose changes.
  • I understand that I must not self-adjust the dose and must report any symptoms of overreplacement promptly.
  • I have disclosed all relevant medical history and current medications to the Clinic.
  • I understand I must seek urgent/emergency care for severe symptoms (chest pain, persistent palpitations, signs of adrenal crisis) and that the Clinic is not an emergency service.
  • I have had the opportunity to ask questions and my questions were answered.
  • I voluntarily consent to commence or continue treatment with the prescribed medication under the regimen agreed with my clinician.