Introduction: Beta-blockers are frequently used as adjunctive therapy in hyperthyroidism to manage adrenergic symptoms, yet their potential to precipitate secondary Raynaud’s phenomenon remains under-recognized. This adverse effect is attributed to β2-adrenoceptor blockade, which impairs peripheral vasodilation and promotes reflex vasoconstriction. Nonselective agents such as propranolol carry this particular risk. Case: A 22-year-old female presented with a 6-month history of palpitations, 11 kg weight loss, and fine tremors. There was no personal or family history of autoimmune or connective tissue disease. She denied any malar rash, joint swelling, alopecia, myopathy, oral ulcers, or uveitis. She also denied using any supplements or any herbal or traditional remedies. Examination revealed tachycardia, fine tremors, and Graves’ ophthalmopathy, but no acropachy or organomegaly. Investigations confirmed Graves’ disease: Free T4 of 73 pmol/L, thyroid-stimulating hormone <0.05 mIU/L, with elevated anti-thyroid peroxidase and antithyroglobulin antibodies. Full blood count, renal, and liver function were unremarkable. She was commenced on carbimazole 20 mg daily and propranolol 40 mg three times daily. After 8 months of treatment, she developed cold-induced digital color changes and skin tightening consistently, suggestive of Raynaud’s phenomenon. Dose reduction of propranolol to 20 mg BD only yielded partial improvement. Propranolol was subsequently substituted with verapamil, a nondihydropyridine calcium channel blocker, resulting in significant resolution of Raynaud’s phenomenon. Conclusion Propranolol-induced Raynaud’s phenomenon is an underrecognized complication in the management of Graves’ disease, and this case illustrates that it may develop insidiously after months of therapy and can persist despite dose reduction. Substitution with verapamil achieves rate control without β2-adrenergic antagonism. Clinicians should maintain a low threshold for recognizing this adverse effect and consider early substitution with verapamil in affected patients. While verapamil does not confer the same adrenergic blockade as propranolol, its vasodilatory properties make it a rational and effective alternative in this context.
Raynaud Disease ; Graves Disease