• History of asthma
• History of hypertension preconception, treated with chlorthalidone and lisinopril
• Lisinopril discontinued preconception
• Methyldopa was ineffective at lowering her blood pressure
• 22 weeks gestational age
• She is intolerant to labetalol due to worsening of her asthma
• Intolerant to hydralazine due to reflex tachycardia and peripheral edema
• No history of allergies
• BMI normal for the stage of pregnancy
• Consistently elevated blood pressure at home and on a recent 24-hour ambulatory blood pressure monitor with blood pressures in the 150-159/90-95 range
• No evidence of gestational diabetes mellitus
• No evidence of fetal distress

Please answer the following questions:

1. Would you continue the patient’s chlorthalidone? Why or why not?
   1. Why did her lisinopril need to be discontinued prior to conception?
   2. What are the concerns with the use of diuretics in pregnancy?
2. What class of antihypertensive drug would you add to her regimen if it was decided to continue chlorthalidone?
   1. What are your rationales for choosing this class of medication?
3. Using provider-level language and scientific evidence, discuss the patient education you would provide about chlorthalidone’s use in pregnancy:
   1. How the drug works at the cellular level in the body to achieve its effects
   2. What the effects of these actions are
   3. Adverse effects, including any methods to mitigate and/or prevent these adverse effects
   4. Precautions and contraindications that would be relevant to this patient
   5. Three drug-to-drug interactions that might occur due to other drugs this patient could be prescribed, including possible consequences of these interactions
   6. The monitoring needed for the diuretic
   7. The monitoring needed for hypertension
   8. Non pharmacologic methods to lower blood pressure

For more details, please refer to the assignment rubric and instructions.

ANSWER

Management of Hypertension in Pregnancy: A Comprehensive Approach

Hypertension during pregnancy presents complex challenges requiring a thorough evaluation and individualized treatment plan. In the case of a 22-week gestational age patient with a history of asthma and hypertension, a careful assessment is essential to ensure optimal maternal and fetal outcomes. Addressing the patient’s medical history, medication regimen, and potential treatment options is crucial to guide decision-making.

Chlorthalidone Continuation

The decision to continue chlorthalidone should be made cautiously, considering the potential risks and benefits. Chlorthalidone, a diuretic, can lower blood pressure by reducing plasma volume through increased urine output. However, its use during pregnancy raises concerns due to its potential to decrease plasma volume, which may adversely affect uteroplacental perfusion and fetal growth. Furthermore, diuretics can lead to electrolyte imbalances, which might increase the risk of preterm labor and other complications. Close monitoring of blood pressure and maternal-fetal well-being is imperative if chlorthalidone is continued.

Lisinopril Discontinuation

Lisinopril, an angiotensin-converting enzyme (ACE) inhibitor, poses significant risks during pregnancy, including fetal renal dysfunction, anuria, and neonatal hypotension. Its discontinuation prior to conception is necessary to prevent potential harm to the developing fetus. ACE inhibitors interfere with fetal renal development by inhibiting the formation of angiotensin II, which plays a crucial role in nephrogenesis. Discontinuation is crucial to avoid renal complications in the fetus.

Antihypertensive Drug Addition

Given the patient’s intolerance to labetalol and hydralazine, and considering her asthma, a suitable antihypertensive class to add to her regimen could be calcium channel blockers (CCBs). CCBs, like nifedipine, reduce peripheral resistance by blocking calcium influx into vascular smooth muscle cells. They have a relatively favorable side effect profile and may not exacerbate asthma symptoms. Individualized dosing and close monitoring of blood pressure and maternal-fetal well-being are necessary.

Patient Education on Chlorthalidone

To provide comprehensive patient education, the following aspects need to be addressed:
Mechanism of Action: Chlorthalidone reduces blood pressure by promoting diuresis, leading to decreased plasma volume and subsequently lowering cardiac output and blood pressure.
Effects: Reduced blood pressure improves maternal and fetal outcomes by optimizing uteroplacental perfusion and minimizing the risk of hypertensive complications.
Adverse Effects: Potential adverse effects include electrolyte imbalances (hypokalemia, hyponatremia), which can be managed by dietary modifications or electrolyte supplements.
Precautions/Contraindications: Patients with a history of gout or diabetes should be monitored closely. Avoid use if allergic reactions occur.
Drug Interactions: Chlorthalidone can interact with non-steroidal anti-inflammatory drugs (NSAIDs) and lithium, potentially affecting renal function and electrolyte balance.
Monitoring: Regular blood pressure monitoring and electrolyte assessments are vital.
Non-pharmacologic Methods: Educate the patient about lifestyle modifications, including maintaining a healthy diet, regular exercise, stress reduction, and adequate sleep.

In conclusion, managing hypertension in pregnancy requires a multidisciplinary approach considering the patient’s medical history, medication interactions, and potential maternal-fetal risks. Tailored education and monitoring ensure informed decision-making and optimal outcomes for both mother and baby.