Should I start amlodipine (calcium channel blocker) 5mg in a 45-year-old female patient with uncontrolled hypertension (blood pressure 160/80 mmHg) on telmisartan (angiotensin II receptor antagonist) 40mg, who also has hypothyroidism on thyroxine (levothyroxine) 75 micrograms (mcg) with an elevated Thyroid-Stimulating Hormone (TSH) level of 12?

Management of Uncontrolled Hypertension in a Patient with Hypothyroidism

Yes, adding amlodipine 5 mg is appropriate for this patient with uncontrolled hypertension (160/80 mmHg) who is already on telmisartan 40 mg, especially given her elevated TSH level.

Blood Pressure Assessment and Goals

The patient presents with:

• 45-year-old female
• Two BP readings of 160/80 mmHg one month apart
• Currently on telmisartan 40 mg
• Hypothyroidism with elevated TSH of 12, on levothyroxine 75 mcg

This patient's blood pressure is clearly above target levels. According to current guidelines, the target blood pressure for most adults should be <130/80 mmHg 1, 2. With systolic BP of 160 mmHg, she has Stage 2 hypertension that requires intensification of therapy.

Addressing Hypothyroidism First

Before focusing solely on antihypertensive therapy, it's important to note:

• The patient has an elevated TSH of 12, indicating suboptimal thyroid replacement
• Untreated or undertreated hypothyroidism can contribute to hypertension
• Optimizing thyroid replacement therapy may help improve blood pressure control

The levothyroxine dose likely needs adjustment, as a TSH of 12 indicates inadequate replacement 3. However, this will not produce immediate blood pressure lowering effects, so antihypertensive therapy should be intensified concurrently.

Antihypertensive Medication Selection

Adding amlodipine 5 mg is appropriate for several reasons:

• Calcium channel blockers (CCBs) like amlodipine are recommended as part of combination therapy with ARBs like telmisartan 1, 2
• Amlodipine is a long-acting dihydropyridine CCB with proven 24-hour efficacy 4, 5
• The combination of telmisartan and amlodipine has shown significant BP reductions in both treatment-naïve and previously treated hypertensive patients 6
• The standard starting dose of amlodipine for hypertension is 5 mg once daily 7

Precautions with Amlodipine

When starting amlodipine 5 mg, be aware of:

1. Peripheral edema: The most common side effect, more common in women

   • Monitor for ankle swelling at follow-up visits
   • If severe, consider reducing to 2.5 mg or switching to another agent

2. Gradual onset: Full effect may take 1-2 weeks

   • Schedule follow-up within 2-4 weeks to assess efficacy

3. Drug interactions: No significant interactions with levothyroxine or telmisartan

   • Safe to use in combination with current medications

4. Dosing considerations:

   • Start with 5 mg once daily as recommended 7
   • Can be increased to 10 mg if needed after 2-4 weeks

Follow-up Plan

1. Start amlodipine 5 mg once daily
2. Increase levothyroxine dose (consult with endocrinology if needed)
3. Recommend home blood pressure monitoring to track response
4. Schedule follow-up in 2-4 weeks to:
   • Assess blood pressure response
   • Check for peripheral edema
   • Review thyroid function tests if available
   • Consider dose adjustments as needed

Alternative Considerations

If amlodipine is not tolerated or contraindicated:

• Consider a thiazide diuretic like chlorthalidone 12.5-25 mg 1, 2
• Consider increasing telmisartan to 80 mg (maximum dose) 1

Conclusion

Adding amlodipine 5 mg to the current telmisartan 40 mg regimen is an evidence-based approach for this patient with uncontrolled hypertension. Simultaneously, addressing the undertreated hypothyroidism by adjusting the levothyroxine dose will provide comprehensive management of both conditions that may be contributing to her elevated blood pressure.