Cases analysis of rational use of medicine (45) Hypertension of Pregnancy

藥學英語園地

Casesanalysisofrationaluseofmedicine(45)HypertensionofPregnancy

1.Patient'sconditions

Patient，19-year-old female,was pregnant for 25 weeks.She had headache,nausea and epigastric pain.Blood pressure was 162/108 mmHg,the repeated measure of BP after an interval of 6 hours was the same as the first time.She had no history of hypertension.

Urinary protein:+

Diagnosis:preeclampsia

2.Drugadministration

25% Magnesium Sulfate Inj 40 ml

5% Glucose Inj 500 ml/iv drip

Hydralazine HCl Tab 10 mg tid

3.Analysis

(1)Preeclampsia:Development of hypertension with albuminuria or edema between the 20th wk of pregnancy and end of the first week postpartum.Eclampsia:coma and/or convulsive seizures in the same time period,without other etiology.

Preeclampsia develops usually in primigravidas and women with preexisting hypertension or vascular disease.If untreated,preeclampsia characteristically smoulders for a variable length of time and suddenly progresses to eclampsia.Eclampsia develops in a few preeclamptic patients and is usually fatal if untreated.A major complication of preeclampsia is placental abruption.

(2)Any pregnant woman who develops a BP of 140/90 mmHg,edema,or albuminuria of ≥1+ or whose BP rises by 30 mmHg systolic or 15 mmHg diastolic must be considered to have preeclampsia.Patients with a BP of ≥160/110 mmHg,marked edema or albuminuria (≥3.0 g/24 h)are considered to have severe preeclampsia.

(3)The treatment of preeclampsia is aimed at preserving the life and health of the mother,the fetus usually also survives.

Therapy for preeclampsia consists of hospitalization with bed rest (left lateral position),control of BP,seizure prophylaxis when signs of impending eclampsia are present and timely delivery.The treatment prior to delivery is to lessen symptoms,and principal agent is magnesium sulfate.

(4)Magnesium Sulfate(MgSO4) has anticonvulsant properties when administered parenterally and is used to control seizures in eclampsia.But something important must be paid attention to before the use of MgSO4.

a.Patient has patellar tendon reflex.

b.Patient's respiration rate is more than 16/min.

c.Urinary output of patient is more than 25 ml/h or 600 ml/24 h.

d.Calcium gluconate 1 gm iv should be prepared as specific antidote for excess MgSO4.

In severe preeclampsia,MgSO4in 5% Glucose Inj.should be infused slowly and continuously with supplemental doses as necessary,then the hyperreflexia that usually accompanies this disorder diminishes,thereby decreasing the risk of convulsions,concomitant lowering of BP usually occurs.If BP does not respond to MgSO4therapy,an iv infusion of urapidil or hydralazine may be started.But BP should never be lowered to <130/80 mmHg,because excessive BP reduction may compromise uteroplacental blood flow and jeopardize the fetus.

Hydralazine,an antihypertensive,has been used for many years in the hypertensive pregnant woman.It has benefits of increasing renal and uteroplacental blood perfusion and cardiac output.But tachycardia,palpitations,headache etc occur now and then with the use of hydralazine,prolonged use of large doses is associated with an increased incidence of lupus erythematosus.

Orally administered calcium channel blockers such as Nifedipine Retard Tablets,can be used in preeclampsia because of their effectiveness and rapid onset of action.

ACEIs,ARBs and β-blockers are usually not recommended in preeclampsia because of harmful effects on fetus.

合理用藥案例分析(45)妊娠高血壓

1.患者簡介

患者，女性，19歲，妊娠25周時，出現(xiàn)頭痛，惡心，上腹部不適，血壓162/108 mmHg,間隔6小時后再測血壓，仍是162/108 mmHg?；颊邿o高血壓患病史。

尿蛋白檢查：+

診斷：子癇前期(原名先兆子癇)

2.用藥

25%硫酸鎂注射液 40 ml

5%葡萄糖注射液 500 ml/靜滴

鹽酸肼屈嗪片 10 mg 3次/d

3.用藥分析

(1)子癇前期：在妊娠第20周到產(chǎn)褥期第1周之間發(fā)生的高血壓，伴蛋白尿或水腫。

子癇：該時期內(nèi)無其他病因?qū)W引起昏迷及/或痙攣發(fā)作。

子癇前期通常發(fā)生于初孕婦及既往有高血壓及血管疾病的婦女。若不加治療，子癇前期一般持續(xù)一段時間后突然發(fā)展為子癇。子癇前期患者中少數(shù)會出現(xiàn)子癇，若不加治療?？芍滤?。子癇前期的主要并發(fā)癥是胎盤早期剝離。

(2)凡孕婦血壓≥140/90 mmHg，水腫或蛋白尿(+)以上，或收縮壓上升30 mmHg，或舒張壓上升15 mmHg者，均應(yīng)考慮子癇前期的存在。患者血壓≥160/110 mmHg，伴明顯水腫或蛋白尿(≥3.0 g/24 h)要視為重度子癇前期。

(3)治療目標是保護母親的生命和健康，并盡量保住胎兒。治療通常要收住院，臥床休息(左側(cè)臥)，控制血壓，當有子癇跡象時要預(yù)防控制其發(fā)作，并適時終止妊娠。終止妊娠前治療緩解其癥狀，首選用藥為硫酸鎂。

(4)注射用硫酸鎂抗驚厥，可用于抗子癇發(fā)作。但硫酸鎂使用前有些問題必須提起注意。

a.患者應(yīng)存在膝腱反射；

b.患者呼吸次數(shù)要大于16次/min；

c.患者尿量要多于25 ml/h或600 ml/24 h；

d.用藥準備10%葡萄糖酸鈣10 ml，作為硫酸鎂過量的解毒劑。

重度子癇前期，硫酸鎂的葡萄糖稀釋液，應(yīng)緩慢連續(xù)靜脈輸注，必要時調(diào)整劑量，給藥后神經(jīng)反射增強減輕，并減少出現(xiàn)痙攣的危險，血壓也隨之降低。如果應(yīng)用硫酸鎂后血壓降低不明顯，則可靜脈滴注烏拉地爾或肼屈嗪。但血壓不要低于130/80 mmHg，過度降壓有損于子宮胎盤血液灌注及胎兒的安全。

作為一降壓藥，肼屈嗪用于妊娠高血壓多年。其優(yōu)點是增加腎臟及子宮胎盤血流及心臟排血量，但隨其應(yīng)用，可發(fā)生心動過速、心悸頭痛等不良反應(yīng)，長期大量應(yīng)用有增加紅斑狼瘡發(fā)病風險?？诜}拮抗劑類，如硝苯地平控釋片，因其效果確實，起效迅速，也可用于子癇前期降壓治療。

血管緊張素轉(zhuǎn)換酶抑制劑，血管緊張素受體拮抗劑及β-受體阻滯劑因其對胎兒有不利影響，通常不用于子癇前期降壓治療。

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