Medications
Individual responses to medications vary greatly. Target the triggers of nausea/vomiting such as motion sensitivity, while ensuring adequate hydration and metabolic balance. If a woman is vomiting constantly, oral dosing of medications will likely be ineffective.
Read our 
brochure on medication strategies!
Learn how to get the most from medications & use them to manage HG most effectively!
Zofran (ondansetron) & Kytril Tips:
- most effective class of drugs for HG & multi-trigger patients,
- dose-dependent drugs - benefits and side-effects increase with the dose,
- often works better if hydrated and combined with other meds,
- higher doses may decrease need for IV's and hospitalization,
- gradual reduction in dose, then frequency, is critical to avoid relapse,
- prevent side-effects like constipation exacerbated by dehydration.
SEROTONIN ANTAGONISTS
Highly selective antagonist of 5-HT3 receptors in the vagus, CTZ (chemotrigger zone) and gut. Mostly Class B drugs. Found to improve symptoms in >80% of women.
More common side-effects: Headache, mild liver function abnormalities,
constipation*, diarrhea
* Proactive, daily bowel management is very important. For information on managing these symptoms, see this article on MedicineNet.
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 considered as a first line drug to minimize symptom severity.
IMPORTANT: Effects are dose dependent. Best taken on a strict schedule and weaned very slowly when asymptomatic for two weeks. May be needed until delivery.
| Drug Name | Min/Max Dosage | Notes | Research Studies |
|
(** Update on Zofran lawsuits) |
4 to 8 mg every 6
hours Can be compounded into a suppository or other form. Dosing throughout pregnancy may prevent relapse or stabilize symptoms. |
Zofran tablets are available as a generic.
Widely available around the world. |
Ondansetron in pregnancy and risk of adverse fetal outcomes. (2013) Secular Trends in the Treatment of Hyperemesis Gravidarum. (2007) Pharmacokinetics of Three Formulations of Ondansetron More research articles on PubMed. |
| Kytril, Sancuso (Granisetron) |
1 mg every 12 hours (IV or orally) Allows twice a day dosing. Also available in transdermal patch form as Sancuso. |
Kytril is available as a generic. | Research articles on PubMed. |
| Mirtazapine (Remergil, Remeron) | May interact with sedatives,
antihistamines, and tricyclic antidepressants. Has both anti-vomiting and anti-depressant effects. |
Mirtazapine
(Remergil) for treatment resistant hyperemesis gravidarum: rescue
of a twin pregnancy. More research articles on PubMed. | |
| Aloxi (palonosetron) |
Dose not established in HG. 0.25 mg IV given for chemo. | Half-life: 40 hr. & only
given once in 5 days. Reimbursement Support Network. |
None for HG yet. Research on PubMed. |
| Anzemet (Dolasetron) |
Dose not established in HG. 50-150 mg orally daily is reported. | Research articles on PubMed. |
SUBSTANCE P/NEUROKININ 1 (NK1) RECEPTOR ANTAGONIST
This is a NEWER class of drugs so minimal safety data is available. No studies for its use in pregnancy are available. We caution the use of this medication class and suggest use as last resort.
Research Links:
- Research on PubMed »
View research articles about Emend use in pregnancy..
| Drug Name | Min/Max Dosage | Notes | Research Studies |
| Emend (Aprepitant) |
80-125 mg per day is dose for chemotherapy Oral and IV |
Typical protocol (prevention of vomiting due to chemotherapy) includes combining with a serotonin antagonists and steroids. | None for HG yet. |
CORTICOSTEROIDS
Cortisone/Corticosteroids - Not recommended until after 8-10 weeks
- Used for refractory hyperemesis
gravidarum, usually in conjunction with ondansetron
- Possible side-effects: blood sugar instability, weight loss, nausea and vomiting, increased risk of
preeclampsia
- Possible fetal complications: reduced birth weight, clefts (if early use), adrenal insufficiency (if exposed to large doses)
-
Inconclusive
concerns over impact on fetal brain development and oral/lip clefts
with prolonged dosing at high levels, and use during the first
trimester.(Collaborative Perinatal Project)
- 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.]
-
Hypothyroid mothers may have an
exaggerated response to corticosteroids
- Diabetic mothers may require as much as a 40% increase in their insulin
when high dose steroids are started.
Drug Classification:
Methylprednisolone: C. Prednisone:
B
(See below for FDA-Assigned Pregnancy Categories)
| Drug Name | Min/Max Dosage | Notes | Research Studies |
| Medrol or Solu-Medrol (Methylprednisolone or Prednisone) | Typical oral dosage is 48 mg
per day for three to five days, followed by slow tapering over two
to three weeks. Limit to one month of therapy if possible. See article for more on dosing. |
Consideration use with serotonin antagonists and/or during weaning from steroids to prevent relapse. | Corticosteroid
therapy in hyperemesis gravidarum More Research on PubMed |
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. Antihistamines with sedative effects can be helpful for sleep.
Research Links:
- HER Foundation Colloborative Research: Antihistamines and other prognostic factors for adverse outcome in hyperemesis gravidarum.
- A review of antihistamines used during pregnancy. J Pharmacol Pharmacother. 2012 Apr;3(2):105-8.
- Research on PubMed »
View more research about hyperemesis gravidarum and antihistamines.
| Drug Name | Min/Max Dosage | Notes | Research Studies |
| Bonine, Antivert, Marezine (Meclizine/Buclizine/Cyclizine) |
Follow directions on the label. | See Medline Plus | |
| Dramamine (Dimenhydrinate) |
50-100 mg every 4-6 hours | Used for motion sickness. | |
| Doxylamine (Unisom) |
25 mg orally at bedtime, 1/2 tablet every 6 hours as needed |
Component of Diclegis/Diclectin. Often taken with vitamin B6. |
|
| Diclectin, Diclegis (doxylamine plus pyridoxine) |
Average dose is 1 tablet in
morning, one in afternoon and two at night. May be given in higher doses up to 12 tablets daily - see research links on right. |
Differs from Unisom/B6 combo
because it is a delayed release formula. |
|
| Benadryl (Diphenhydramine or Gravol) |
25 mg IVP/orally every 4–6 hours | ||
| Tigan (Trimethobenzamide) |
25 mg orally every 6-8 hours 200 mg IM every 6-8 hours |
||
| Vistaril, Atarax (Hydroxyzine) |
25 mg orally every 6 hours | Syrup available Helpful for insomnia |
ANTIDOPAMINERGICS: PHENOTHIAZINES
Common side-effects: Drowsiness, hypotension, dry mouth, constipation,
urinary retention, rash, extrapyramidal symptoms (EPS)*, restlessness,
confusion, fatigue. Phenothiazines lower seizure threshold.
*Call your doctor immediately for involuntary
movements, tremors and rigidity, body restlessness, muscle contractions
and changes in breathing and heart rate.
Mostly Class C drugs.
May be helpful in mild and moderate cases or used in conjunction with other medications. Co-administer antihistamines to minimize side-effects.
| Drug Name | Typical Min/Max Dosage | Notes | Research Studies |
| Compazine, Stemetil (Prochlorperazine) |
5–10 mg orally, IM, or
IV every 6–8 hours 25 mg every 6–8 hours rectal |
Risk of EPS increased with metoclopramide (Reglan). Treat/prophylax for EPS with Benadryl. | Research articles on PubMed. |
| Phenergan (Promethazine) |
12.5–25 mg IVP/orally, IM/PR every 4-6 hours *IV dose contains sulfite |
Warning: IV or injected doses can cause tissue damage. More info available on fda.gov. GIVE IV dose SLOWLY to avoid contractions. Side-effects of anxiety, sedation, and restlessness common and may limit use. |
Research articles on PubMed. |
| Thorazine (Chlorpromazine) |
Oral/IM 12.5–25mg every
4–6 hours Rectal 50–100 mg every 6–8 hours |
May increase risk of fetal malformations. May cause muscle spasms in neck/face and/or difficulty with speech. |
Research articles on PubMed. |
| Haldol (Haloperidol) |
1–2 mg orally/IM every 8 hours | Extrapyramidal symptoms (EPS) more common. May cause constipation. | Research articles on PubMed. |
ANTIREFLUX MEDICATIONS
- Common side-effects: Headache, dizziness, difficulty sleeping,
constipation, diarrhea.
- Helpful both for reflux
and for prevention of gastric irritation which worsens nausea.
- Use
when a woman is vomiting frequently and/or
cannot eat and drink sufficiently.
-
Studies suggest they are safe during pregnancy. Mostly Class B drugs. Omeprazole (Prilosec, Zegerid) are class C.
| Drug Name | Min/Max Dosage | Notes | Research Studies |
| Zantac (Ranitidine) |
50 mg IV every 8 hours or 150 mg orally daily or twice a day | Reprod Toxicol. 2005 Pregnancy outcome after exposure to ranitidine and other H2-blockers. | |
| Tagamet (Cimetidine) |
Not recommended during pregnancy due to anti-androgenic effects in humans. | ||
| Pepcid (Famotidine) |
20 mg IVP/orally every 12 hours | Reprod Toxicol. 2005 Pregnancy outcome after exposure to ranitidine and other H2-blockers. | |
| Prevacid (Lansoprazole) |
30-60 mg/day | AAFP 2002 Proton Pump Inhibitors: An Update. Use of proton pump inhibitors during pregnancy and rates of major malformations: a meta-analysis. |
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.
- Helpful in women who vomit after eating/drinking, and who do not respond
to Zofran alone.
- Sometimes
used in conjunction with meds such as Zofran.
-
Use with antihistamines
to minimize side-effects.
-
Side-effects are very common and can be severe, especially when given quickly through an IV.
Common side-effects: Drowsiness, dizziness, abdominal pain, diarrhea,
restlessness, EPS*, depression
(*Report extrapyramidal symptoms immediately: involuntary
movements, tremors and rigidity, body restlessness, muscle contractions
and changes in breathing and heart rate.)
| Drug Name | Min/Max Dosage | Notes | Research Studies |
| Reglan or Maxeran (Metoclopramide) |
10–20 mg IV/orally every
6 hours May be given orally, SQ pump, IV (SLOWLY) |
FDA recommends this drug be taken for up to 12 weeks. Risks of serious side-effects increase thereafter.
Increased CNS side effects when used with phenothiazines. Side-effects common and may limit use. Use with antihistamines. Class B drug. |
Ondansetrone or metoclopromide? Which is more effective in severe nausea and vomiting of pregnancy? Ondansetron compared with metoclopramide for hyperemesis gravidarum: a randomized controlled trial. The
safety of metoclopramide during pregnancy |
| Propulsid (Cisapride) |
10 mg orally every 6 hours, before meals and at bedtime (maximum dose 20 mg every 6 hours) | No CNS side effects. Limited availability in US. |
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.
| Drug Name | Min/Max Dosage | Notes | Research Studies |
| Scopolamine, Belladonna (Hyoscine Hydrobromide) |
0.3 to 0.65 mg administered IV, intramuscularly or subcutaneously every 6 to 8 hours as needed 1.5 mg transdermal disc behind the ear every 3 days |
Effectiveness studies are lacking. |
MISCELLANEOUS & NEW MEDICATIONS
| Drug Name | Min/Max Dosage | Notes | Research Studies |
| Catapres-TTS (Clonidine) |
New medication being used for HG. | Transdermal clonidine in the treatment of severe hyperemesis. A pilot randomised control trial: CLONEMESI. | |
| Gabapentin (Neurontin) |
In trials for use in HG. Considered as last resort in patients who have exhausted other medication categories. | Potential maternal symptomatic benefit of gabapentin and review of its safety in pregnancy. Research articles on PubMed. |
|
| Thiamine (Vitamin B1) |
5 mg/day minimum; Considered non-toxic. For HG: 100-500 mg BID IV. IM contraindicated. Should be given orally before and during pregnancy as tolerated. |
Body's stores depleted in < 3 weeks. Infographic on thiamin deficiency in HG. |
Iatrogenic wernicke encephalopathy in a patient with severe hyperemesis gravidarum. Wernicke's encephalopathy induced by hyperemesis gravidarum. |
Pyridoxine Cobalamin, Cyanocobalamin, Hydroxocobalamin (Vitamin B12)
|
20-75 mg/day 100 mcg/day |
Paresthesias may occur if B6 is taken
in high doses. Note: reactions to vitamins are rare but possible. |
Serious adverse drug reaction in a woman with hyperemesis gravidarum after first exposure to vitamin B complex containing vitamins B1, B6 and B12. |
|
Each tablet contains 25mg of Vitamin B6 (as Pyridoxine Hydrochloride) and 100mg of Ginger Root PE 5% Gingerois (Zingiber Officinalis) |
3 tablets daily
|
A prescription is NOT required for this medication. | |
| Ginger | 250 mg orally every 6 hours | Helpful as adjunctive therapy. | |
| Emetrol (Fructose, Dextrose, and Phosphoric Acid) |
One or two tablespoonfuls upon arising and every three hours as needed. | Helpful as adjunctive therapy. | |
| Marijuana (Cannabis) or the pharmaceutical extract: Marinol (Dronabinol) |
Dose not established for HG. | Effects of prenatal exposure to marijuana. Research on PubMed |
|
| Benzodiazepine Derivatives: Valium (Diazepam) |
Dose not established for HG. | Class D drug. | Evaluation of treatment of hyperemesis gravidarum using parenteral fluid with or without diazepam. |
| Neuroleptic: Inapsine (Droperidol) |
Gerald G. Briggs Briggs (LBMMC) Hyperemesis Protocol |
Use with diphenhydramine to
avoid side-effects. Category C drug. |
Droperidol
and diphenhydramine in the management of hyperemesis gravidarum. Droperidol-diphenhydramine for hyperemesis gravidarum. |
** IM = Intramuscular (injection)
** IV = Intravenous
** IVP = Intravenous push (injected into an IV)
** PR = Per rectum
** SQ = subcutaneous (injected under the skin)
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.
Updated on: Sep. 15, 2022
The Chronicles of Nausea
Beyond Morning Sickness