Thermogenesis in Hyperthyroidism and Effect of Anti-Adrenergic Therapy

Inclusion criteria

• Informed Consent as documented by signature
• Age 18 to 70 years
• Hyperthyroidism: Thyroid-stimulating Hormone (TSH) below 0.2 mU and free T4 at or above 25 pmol/L or free T3 at or above 8 pmol/L.

Exclusion criteria

• Contraindications to propranolol: hypersensitivity or allergy
• Therapy with a beta blocker for reasons other than hyperthyroidism (e.g. cardiac arrhythmia or heart failure)
• Treatment with amiodarone
• Women who are pregnant or breast feeding,
• Intention to become pregnant during the course of the study,
• History of asthma or chronic obstructive pulmonary disease
• Occlusive peripheral artery disease; Raynaud's syndrome.
• Other clinically significant concomitant disease states:

• Known renal failure (GFR < 50 ml/min)
• Known hepatic dysfunction
• known heart failure or unstable angina pectoris
• Known or suspected non-compliance, drug or alcohol abuse,
• Inability to follow the procedures of the study, e.g. due to language problems, psychological disorders, dementia, etc. of the participant,
• Participation in another study with investigational drug within the 30 days preceding and during the present study,
• Previous enrolment into the current study,
• Enrolment of the investigator, his/her family members, employees and other dependent persons.
• ECG-criteria

• Resting heart rate below 60 bpm
• Complete left bundle branch block
• Atrioventricular block (AV-block) grade 2 or 3