What is the recommended treatment and dosing for a 65-year-old female patient with a history of Coronary Artery Disease (CAD), presenting with tremors, weight loss, and lab results showing hyperthyroidism (low Thyroid-Stimulating Hormone (TSH), elevated free T4 and free T3), and how does neomercazole (carbimazole) fit into the treatment plan?

Management of Hyperthyroidism in a 65-Year-Old Female with CAD

For a 65-year-old female with CAD presenting with tremors, weight loss, low TSH, and elevated T3/T4, carbimazole (neomercazole) should be initiated at 20 mg/day as the first-line treatment.

Diagnosis and Clinical Assessment

This patient presents with classic symptoms of hyperthyroidism:

• Tremors
• Weight loss
• Laboratory confirmation: Low TSH with elevated T3/T4

These findings are consistent with overt hyperthyroidism, which requires prompt treatment, especially given her age and CAD history.

Treatment Approach

First-Line Medication

• Carbimazole (Neomercazole) Dosing:
  • Starting dose: 20 mg/day for mild to moderate hyperthyroidism
  • For severe hyperthyroidism (very high T3/T4 levels), 40 mg/day may be considered 1
  • Administer as a single daily dose or divided into 2-3 doses

Monitoring and Dose Adjustment

• Check thyroid function tests (TSH, free T3, free T4) after 4 weeks
• Expect T4 to normalize before T3 during treatment 2
• Adjust dose based on response:
  • When euthyroid: Reduce to maintenance dose of 5-15 mg/day
  • Continue for 12-18 months before considering discontinuation

Special Considerations for CAD

• Beta-blocker therapy is essential in this patient due to:

  1. History of CAD
  2. Symptomatic hyperthyroidism (tremors)
  3. Age >65 years

• Beta-blocker recommendation:

  • Propranolol 10-40 mg three times daily OR
  • Metoprolol 25-50 mg twice daily 3, 4
  • Target heart rate: 60-80 beats per minute

Rationale for Treatment Selection

1. Carbimazole is appropriate because:

   • It effectively reduces thyroid hormone production
   • It's suitable for elderly patients with comorbidities
   • It allows for gradual normalization of thyroid function

2. Beta-blockers are crucial because:

   • They control adrenergic symptoms (tremors)
   • They provide cardioprotection for her CAD 3
   • They help prevent thyroid storm during initial treatment

Monitoring and Follow-up

• Weekly clinical assessment for first month

• Monitor for:

  • Agranulocytosis (rare but serious side effect)
  • Liver function abnormalities
  • Skin rash
  • Improvement in symptoms (tremor, weight)

• Laboratory monitoring:

  • TFTs at 4 weeks, then every 4-6 weeks until stable
  • CBC with differential at baseline and if fever/infection occurs
  • Liver function tests at baseline and periodically

Important Cautions

1. CAD management considerations:

   • Hyperthyroidism increases myocardial oxygen demand and can worsen angina
   • Ensure adequate beta-blockade before starting carbimazole
   • Monitor for cardiac symptoms during treatment

2. Elderly-specific concerns:

   • Increased risk of adverse drug effects
   • Particular attention to drug dosing and side effects 3
   • Risk of atrial fibrillation with untreated hyperthyroidism

3. Avoid overtreatment:

   • Iatrogenic hypothyroidism can occur, especially with higher doses 1
   • Hypothyroidism may worsen cardiovascular outcomes

Alternative Options

If carbimazole is not tolerated or contraindicated:

• Propylthiouracil (PTU) can be used as an alternative
• Radioactive iodine therapy may be considered after stabilization with antithyroid drugs
• Thyroidectomy is generally reserved for patients who fail medical therapy

Remember that treating hyperthyroidism in this patient with CAD is a priority, as uncontrolled hyperthyroidism significantly increases cardiovascular risk and mortality.