Common Medications

SEROTONIN ANTAGONISTS
Highly selective antagonist of 5-HT3 receptors in the vagus, CTZ (chemotrigger zone) and gut. Mostly Class B drugs.

Often effective in mothers who have multiple triggers (smell, motion, etc.), a history of hormone sensitivity, and/or moderate to severe vomiting. If a woman has a history of HG that responded to serotonin antagonists, it should be used early and as a first line drug to minimize severity.

IMPORTANT: Effects are dose dependent. Expensive intravenous therapies may sometimes be avoided if higher doses are used. Best taken on a strict schedule and weaned very slowly when asymptomatic for over two weeks. It is not uncommon for women to require this medication until delivery. Different brands may have different effects.

CORTICOSTEROIDS
Cortisone/Corticosteroids - Not recommended until after 8-10 weeks
Some possible side-effects include weight loss, nausea and vomiting.

Steroids are used for refractory hyperemesis gravidarum; however, there is some concern over fetal brain development with prolonged dosing at high levels and use during the first trimester. No studies have proven a link and the HER Foundation has not heard such reports from women with HG. The typical treatment is a steroid burst with a rapid taper similar to what is used in acute asthma attacks. [Most studies of asthma patients using steroids show no adverse fetal effects.]

Women with hypothyroidism may have an exaggerated response to corticosteroids; thus any steroid should be used with caution in these mothers. Also, women with Type 1 Diabetes may require as much as a 40% increase in their insulin when high dose steroids are started.

Complications including reduced birth weight, increased risk of preeclampsia, and increased risk of oral and lip clefts have been reported when corticosteroids were administered during early pregnancy. However, the Collaborative Perinatal Project monitored 50,282 mother-child pairs, 34 of which had first-trimester exposure to cortisone. No evidence of a relationship to congenital defects was observed. If these drugs are used during pregnancy, the potential risks should be discussed. Babies born to women receiving large doses of corticosteroids during pregnancy should be monitored for signs of adrenal insufficiency and appropriate therapy initiated, if necessary.

More Info on Steroid Therapy »

Drug Classification:
Methylprednisolone is classified as pregnancy category C. Prednisone is classified as category B but cortisone is classified as pregnancy category D. This probably reflects the fact that cortisone is more commonly used during pregnancy than is prednisone and therefore, more reports of problems have been associated with cortisone than prednisone, and not the fact that it is a more potent teratogen. Corticosteroids cross the placenta. [From: Clinical Pharmacology 2000]

(See below for FDA-Assigned Pregnancy Categories for Drugs)

ANTIHISTAMINES
Common side-effects: Drowsiness, dry mouth, blurred vision, constipation, urinary retention, restlessness, insomnia, sedation, upset stomach, nervousness, headache.

Mostly Class B drugs

Effective for MILD cases of nausea and vomiting during pregnancy or as adjunctive therapy with more potent medications. Women mostly sensitive to motion may benefit most. Antihistamines with sedative effects can be helpful for sleep.

ANTIDOPAMINERGICS: PHENOTHIAZINES
Common side-effects: Drowsiness, hypotension, dry mouth, constipation, urinary retention, rash, extrapyramidal symptoms (EPS), restlessness, confusion, fatigue.

Mostly Class C drugs.

May be helpful in mild and moderate cases or used in conjunction with other medications. Consider co-administration of antihistamines to minimize side-effects.

(Extrapyramidal symptoms include: involuntary movements, tremors and rigidity, body restlessness, muscle contractions and changes in breathing and heart rate.)

ANTIREFLUX MEDICATIONS
Common side-effects: Headache, dizziness, difficulty sleeping, constipation, diarrhea.

This class of drugs is helpful both for reflux and for prevention of gastric irritation which worsens nausea. They should be considered whenever a woman is vomiting frequently and/or cannot eat and drink sufficiently. Studies suggest they are safe during pregnancy. Mostly Class B drugs. [This list is not inclusive of all medications available.]

PROKINETIC AGENTS
Reglan blocks dopamine receptors in the CTZ (chemoreceptor trigger zone) and increases the CTZ threshold & decreases the sensitivity of visceral nerves that transmit afferent impulses from the GI tract to the vomiting center.

May be helpful in women who typically vomit after eating/drinking. Their main symptoms often are GI specific (v. motion sickness or sensitivity to light/sound) and these women may or may not respond to other medications such as Zofran. These drugs are sometimes used in conjunction with meds such as Zofran. Use with antihistamines to minimize side-effects.

Common side-effects: Drowsiness, dizziness, abdominal pain, diarrhea, restlessness, EPS, depression

(Extrapyramidal symptoms include: involuntary movements, tremors and rigidity, body restlessness, muscle contractions and changes in breathing and heart rate.)

ANTICHOLINERGICS/ANTISPASMODICS
Common side-effects: Confusion; dizziness, lightheadedness (continuing) or fainting; eye pain; skin rash or hives.

Should not be used in treatment of hyperemesis gravidarum. These agents slow gastric emptying and prolong GI transit time. Since slowed gastric emptying is part of the etiology of HG, these agents are inappropriate.

MISCELLANEOUS

FDA-Assigned Pregnancy Categories for Drugs (United States Classification)

• Category A
  Adequate and well-controlled studies have failed to demonstrate a risk to the fetus in the first trimester of pregnancy (and there is no evidence of risk in later trimesters).
   
• Category B
  Animal reproduction studies have failed to demonstrate a risk to the fetus and there are no adequate and well-controlled studies in pregnant women.
   
• Category C
  Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.
   
• Category D
  There is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience or studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.
   
• Category X
  Studies in animals or humans have demonstrated fetal abnormalities and/or there is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience, and the risks involved in use of the drug in pregnant women clearly outweigh potential benefits.

Excerpted from Drug Information for the Health Care Professional, USP-DI, Volume 1A, 11th ed., 1991.