Pregnancy, Preeclampsia
Treatment and Medication
Treatment
Prehospital Care:
- Oxygen via facemask
- Intravenous access
- Cardiac monitoring
- Transportation of patient in left lateral decubitus position
- Seizure precautions
Emergency Department Care: In the emergency setting, control of BP and seizures should be priorities. Definitive therapy is delivery of the fetus, although preeclampsia may paradoxically emerge in postpartum patients. In general, the further the pregnancy is from term, the greater the impetus to manage the patient medically.
- BP control
- Goal is to lower BP to prevent cerebrovascular and cardiac complications while maintaining uteroplacental blood flow.
- Control of mildly increased BP does not appear to improve perinatal morbidity or mortality, and, in fact, it may reduce birth weight.
- Antihypertensive treatment is indicated for diastolic blood pressure above 105 mm Hg and systolic pressure above 160 mm Hg, though patients with chronic hypertension may tolerate higher values.
- The goal is to maintain diastolic blood pressure between 90 and 100 mm Hg and systolic pressure between 140 and 155 mm Hg.
- Control of seizures
- Active seizures should be treated with intravenous magnesium sulfate as a first-line agent.
- Prophylactic treatment with magnesium sulfate is indicated for all patients with severe preeclampsia. No consensus exists about whether patients with mild preeclampsia (elevated blood pressure without evidence of end-organ damage) need to be on magnesium seizure prophylaxis.
- Magnesium levels, respiratory rate, reflexes, and urine output must be monitored to detect magnesium toxicity.
- For seizure refractory to magnesium sulfate therapy, benzodiazepines and/or phenytoin may be considered.
Consultations: Immediate obstetric consultation is warranted for all patients presenting with preeclampsia.
Medication
Magnesium sulfate is the first-line treatment for prevention of primary and recurrent eclamptic seizures. For eclamptic seizures refractory to magnesium sulfate, lorazepam and phenytoin may be used as second-line agents.
In the setting of severe hypertension (systolic BP >160 mm Hg, diastolic >110 mm Hg), antihypertensive treatment is recommended. Antihypertensive treatment decreases the incidence of cerebrovascular problems, but it does not alter the progression of preeclampsia.
Traditionally, hydralazine has been used for control of severe hypertension in women with preeclampsia. However, conflicting evidence exists regarding the side effects and maternal/fetal outcomes when compared with labetalol and nifedipine.
Drug Category: Anticonvulsants
Agents that inhibit smooth muscle contractions are used.
| Magnesium sulfate -- First-line therapy for seizure prophylaxis. Antagonizes calcium channels of smooth muscle. Indicated in severe preeclampsia, eclampsia, and preeclampsia in the near term. Administer IV/IM for seizure prophylaxis in preeclampsia. Use IV for quicker onset of action in true eclampsia. | |
| Adult Dose | 4-6 g IV over 20 min with maintenance of 1-2 g/h |
|---|---|
| Pediatric Dose | Not established |
| Contraindications | Documented hypersensitivity; heart block; Addison disease; myocardial damage; severe hepatitis |
| Interactions | Concurrent use with nifedipine may cause hypotension and neuromuscular blockade; may increase neuromuscular blockade seen with aminoglycosides and potentiate neuromuscular blockade produced by tubocurarine, vecuronium, and succinylcholine; may increase CNS effects and toxicity of CNS depressants, betamethasone, and cardiotoxicity of ritodrine |
| Pregnancy | A - Safe in pregnancy |
| Precautions | Magnesium sulfate may alter cardiac conduction leading to heart block in digitalized patients; respiratory rate, deep tendon reflex, and renal function should be monitored when electrolyte is administered parenterally; caution when administering magnesium sulfate dose since may produce significant hypotension or asystole; in overdose, calcium gluconate, 10-20 mL IV of 10% solution, can be given as antidote for clinically significant hypermagnesemia |
| Lorazepam (Ativan) -- Sedative hypnotic with short onset of effects and relatively long half-life. By increasing the action of gamma-aminobutyric acid (GABA), which is a major inhibitory neurotransmitter in the brain, may depress all levels of CNS, including limbic and reticular formation. Important to monitor patient's blood pressure after administering dose. Adjust as necessary. | |
| Adult Dose | 4 mg/dose IV slowly over 2-5 min and repeat in 10-15 min prn; cumulative dose of 8 mg/d typically considered maximum 1-10 mg/d PO/IV/IM divided bid/tid |
|---|---|
| Pediatric Dose | Infants and children: 0.1 mg/kg IV slowly over 2-5 min; repeat prn in 10-15 min at 0.05 mg/kg; not to exceed 4 mg/dose Adolescents: 0.07 mg/kg IV slowly over 2-5 min and repeat in 10-15 min prn; not to exceed 4 mg/dose |
| Contraindications | Documented hypersensitivity; preexisting CNS depression, hypotension, and narrow-angle glaucoma; reversal agents (eg, flumazenil) contraindicated when lorazepam used for life-threatening conditions (eg, control of intracranial pressure or status epilepticus) |
| Interactions | Toxicity of benzodiazepines in CNS increases when used concurrently with alcohol, phenothiazines, barbiturates, and MAO inhibitors |
| Pregnancy | D - Unsafe in pregnancy |
| Precautions | Caution in renal or hepatic impairment, myasthenia gravis, organic brain syndrome, or Parkinson disease |
| Phenytoin (Dilantin) -- Phenytoin has been used successfully in eclamptic seizures, but cardiac monitoring is required secondary to associated bradycardia and hypotension. Central anticonvulsant effect of phenytoin is by stabilizing neuronal activity by decreasing the ion flux across depolarizing membranes. Some benefits to using phenytoin are that it can be continued orally for several days until the risk of eclamptic seizures has subsided, it has established therapeutic levels that are easily tested, and no known neonatal adverse effects are associated with short-term usage. | |
| Adult Dose | 10 mg/kg loading dose infused IV no faster than 50 mg/min, followed by maintenance dose started 2 h later at 5 mg/kg |
|---|---|
| Pediatric Dose | Administer as in adults |
| Contraindications | Documented hypersensitivity; sinoatrial block; second- and third-degree AV block; sinus bradycardia; Adams-Stokes syndrome |
| Interactions | Amiodarone, benzodiazepines, chloramphenicol, cimetidine, fluconazole, isoniazid, metronidazole, miconazole, phenylbutazone, succinimides, sulfonamides, omeprazole, phenacemide, disulfiram, ethanol (acute ingestion), trimethoprim, and valproic acid may increase phenytoin toxicity Phenytoin effects may decrease when taken concurrently with barbiturates, diazoxide, ethanol (chronic ingestion), rifampin, antacids, charcoal, carbamazepine, theophylline, and sucralfate Phenytoin may decrease effects of acetaminophen, corticosteroids, dicumarol, disopyramide, doxycycline, estrogens, haloperidol, amiodarone, carbamazepine, cardiac glycosides, quinidine, theophylline, methadone, metyrapone, mexiletine, oral contraceptives, valproic acid |
| Pregnancy | D - Unsafe in pregnancy |
| Precautions | Perform blood counts and urinalyses when therapy is begun and at monthly intervals for several months thereafter to monitor for blood dyscrasias; discontinue use if a rash appears, and do not resume use if rash is exfoliative, bullous, or purpuric; rapid IV infusion may result in death from cardiac arrest, marked by QRS widening; caution in acute intermittent porphyria and diabetes (may elevate blood sugar levels); discontinue use if hepatic dysfunction occurs |
Drug Category: Antihypertensives
These agents are used to decrease systemic resistance and help reverse uteroplacental insufficiency.
| Hydralazine (Apresoline) -- First-line therapy against preeclamptic hypertension. Decreases systemic resistance through direct vasodilation of arterioles, resulting in reflex tachycardia. Reflex tachycardia and resultant increased cardiac output helps reverse uteroplacental insufficiency, a key concern when treating hypertension in a patient with preeclampsia. Adverse effects to the fetus are uncommon. | |
| Adult Dose | 5-10 mg IV; repeat q20min to maximum of 60 mg |
|---|---|
| Pediatric Dose | Not established |
| Contraindications | Documented hypersensitivity; mitral valve rheumatic heart disease |
| Interactions | MAO inhibitors and beta-blockers may increase hydralazine toxicity; pharmacologic effects of hydralazine may be decreased by indomethacin |
| Pregnancy | C - Safety for use during pregnancy has not been established. |
| Precautions | Hydralazine has been implicated in myocardial infarction; caution in suspected coronary artery disease |
| Labetalol (Normodyne) -- Second-line therapy that produces vasodilatation and decreases in systemic vascular resistance. Has alpha-1 and beta-antagonist effects and beta2-agonist effects. Has more rapid onset than hydralazine and less overshoot hypotension. Dosage and duration of labetalol is more variable. Adverse effects to fetus are uncommon. | |
| Adult Dose | 50-100 mg IV; repeat q30min to a maximum of 300 mg |
|---|---|
| Pediatric Dose | Not established |
| Contraindications | Documented hypersensitivity; cardiogenic shock; pulmonary edema; bradycardia; atrioventricular block; uncompensated congestive heart failure; reactive airway disease; severe bradycardia |
| Interactions | Decreases effect of diuretics and increases toxicity of methotrexate, lithium, and salicylates; may diminish reflex tachycardia, resulting from nitroglycerin use, without interfering with hypotensive effects; cimetidine may increase labetalol blood levels; glutethimide may decrease labetalol effects by inducing microsomal enzymes |
| Pregnancy | C - Safety for use during pregnancy has not been established. |
| Precautions | Caution in impaired hepatic function; discontinue therapy if signs of liver dysfunction; in elderly patients, a lower response rate and higher incidence of toxicity may be observed |
| Nifedipine (Procardia) -- Relaxes coronary smooth muscle and produces coronary vasodilation, which, in turn, improves myocardial oxygen delivery. Sublingual administration is generally safe, despite theoretical concerns. | |
| Adult Dose | 10-30 mg IR cap PO tid; not to exceed 120-180 mg/d 30-60 mg SR tab PO qd; not to exceed 90-120 mg/d |
|---|---|
| Pediatric Dose | 0.25-0.5 mg/kg/dose PO tid/qid prn |
| Contraindications | Documented hypersensitivity |
| Interactions | Fentanyl and alcohol may increase hypotensive effects; calcium channel blocker may increase cyclosporine levels; H2 blockers (cimetidine), erythromycin, nafcillin, and azole antifungals may increase toxicity (avoid combination or monitor closely); carbamazepine may reduce bioavailability (avoid this combination); rifampin may decrease levels (monitor and adjust dose of calcium channel blocker) |
| Pregnancy | C - Safety for use during pregnancy has not been established. |
| Precautions | May cause lower extremity edema; allergic hepatitis has occurred but is rare |
| « Previous Page | Section 3 of 4 |
|
||||
[ CLOSE WINDOW ]
Bibliography
- Doan-Wiggins L: Hypertensive disorders of pregnancy. Emerg Med Clin North Am 1987 Aug; 5(3): 495-508[Medline].
- Frakes MA, Richardson LE: Magnesium sulfate therapy in certain emergency conditions. Am J Emerg Med 1997 Mar; 15(2): 182-7[Medline].
- Lew M, Klonis E: Emergency management of eclampsia and severe pre-eclampsia. Emerg Med (Fremantle) 2003 Aug; 15(4): 361-8[Medline].
- Lipstein H, Lee CC, Crupi RS: A current concept of eclampsia. Am J Emerg Med 2003 May; 21(3): 223-6[Medline].
- Ogle ME, Sanders AB: Preeclampsia. Ann Emerg Med 1984 May; 13(5): 368-70[Medline].
- Powers DR, Papadakos PJ, Wallin JD: Parenteral hydralazine revisited. J Emerg Med 1998 Mar-Apr; 16(2): 191-6[Medline].
- Probst BD: Hypertensive disorders of pregnancy. Emerg Med Clin North Am 1994 Feb; 12(1): 73-89[Medline].
- Sibai B, Dekker G, Kupferminc M: Pre-eclampsia. Lancet 2005 Feb 26-Mar 4; 365(9461): 785-99[Medline].
- Wagner LK: Diagnosis and management of preeclampsia. Am Fam Physician 2004 Dec 15; 70(12): 2317-24[Medline].
[ CLOSE WINDOW ]
Synonyms And Related Keywords
preeclampsia, HTN, hypertensive disease in pregnancy, pregnancy-induced hypertension, toxemia of pregnancy, hypertension, proteinuria, new-onset nondependent edema, seizure activity, eclampsia, seizure in pregnancy, microangiopathic hemolytic anemia, HELLP syndrome, hypertensive encephalopathy
