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Diclegis vs Phenergan
Introduction
For patients dealing with nausea and vomiting, particularly during pregnancy, certain drugs that impact the body's natural substances which trigger these symptoms can be helpful. Diclegis and Phenergan are two such medications often prescribed for this purpose. They each work by different mechanisms but both have effects in alleviating nausea and vomiting.
Diclegis is a combination of doxylamine (an antihistamine) and pyridoxine (a form of vitamin B6), designed to directly soothe the stomach lining while also indirectly affecting brain chemicals linked to nausea sensations. This medication is FDA-approved specifically for morning sickness in pregnant women.
Phenergan, on the other hand, contains promethazine — an antihistamine that works primarily by blocking histamines produced by the body during allergic reactions. Additionally, it affects parts of the brain responsible for triggering feelings of sickness (nausea) and causing you to vomit.
Diclegis vs Phenergan Side By Side
| Attribute | Diclegis | Phenergan |
|---|---|---|
| Brand Name | Diclegis | Phenergan |
| Contraindications | Should not be taken if using or have recently used monoamine oxidase inhibitors (MAOIs). | Should not be used in children under two years due to severe respiratory depression risks. Should not be taken if using or have recently used monoamine oxidase inhibitors (MAOIs). |
| Cost | The price of 60 tablets averages around $430, with generic versions costing significantly less, ranging from about $0.85 - $2 per tablet. | The price for 12.5 mg ranges from $30-$50 for 30 tablets, with generic promethazine being even cheaper, typically costing between $0.20 and $.40/tablet. |
| Generic Name | doxylamine-pyridoxine | promethazine |
| Most Serious Side Effect | Symptoms of a serious liver disease: persistent nausea/vomiting, severe stomach/abdominal pain, dark urine, yellowing eyes/skin. | Severe dizziness or feeling like you might pass out, twitching or uncontrollable movements of your eyes, lips, tongue, face, arms, or legs. |
| Severe Drug Interactions | MAOIs require approximately 5 weeks to clear from the system before starting treatment with Diclegis to prevent dangerous interactions. | MAOIs require approximately 5 weeks to clear from the system before starting treatment with Phenergan to prevent dangerous interactions. |
| Typical Dose | Begins with two tablets at bedtime, with the possibility of adding one in the morning and another in the mid-afternoon if necessary. The maximum daily dose is four tablets. | Treatment typically starts at a dosage of 12.5–25 mg/day, taken before sleeping or after meals. The dose can be increased to 50 mg/day if needed for severe symptoms. |
What is Diclegis?
Diclegis (generic name doxylamine-pyridoxine) and Phenergan (generic name promethazine) are both medications used to treat nausea and vomiting, particularly in pregnant women. Diclegis is a combination of an antihistamine and vitamin B6, specifically developed to treat morning sickness during pregnancy. It was first approved by the FDA in 2013, re-marketing an older drug with a proven safety record for use during pregnancy. Diclegis works by blocking certain natural substances that cause gastric upset.
Phenergan on the other hand has been around much longer; it was initially approved by the FDA back in 1951. While it can be used for similar symptoms as Diclegis, its uses extend beyond just treating morning sickness and can be utilized for allergies, motion sickness and even as a sedative before/after surgeries or medical procedures. Unlike Diclegis which primarily influences histamines related to digestion issues, Phenergan affects various neurotransmitters such as dopamine leading to potential side effects like drowsiness or confusion.
What conditions is Diclegis approved to treat?
Diclegis is approved for the treatment of different conditions, including:
- Nausea and vomiting during pregnancy when conservative management has failed
- Morning sickness associated with pregnancy
On the other hand, Phenergan is used to treat a wide range of ailments such as:
- Allergic reactions
- Motion sickness
- Pre and postoperative sedation
- As an adjunctive therapy in treating pain
How does Diclegis help with these illnesses?
Diclegis is a medication used to manage nausea and vomiting during pregnancy. It works by combining pyridoxine, a form of vitamin B6, and doxylamine, an antihistamine. Pyridoxine helps the body process certain amino acids that are needed for normal functioning of nerves and muscles while also aiding in the breakdown of proteins, fats, and carbohydrates from foods. Doxylamine blocks histamines which have been linked to causing nausea and vomiting. By combining these two substances Diclegis can help limit the negative effects of morning sickness helping pregnant women feel better.
On the other hand, Phenergan (promethazine) is another medication used to treat nausea and vomiting but it also has sedative properties due to its antihistaminic effect. This makes it less ideal for use during daytime or when alertness is necessary as it may cause drowsiness or impaired motor skills.
What is Phenergan?
Phenergan is the brand name for promethazine, which is a first-generation antihistamine that works by blocking the effects of histamine in your body. It also has sedative properties and can be used as a premedication before anesthesia due to its antiemetic (preventing nausea and vomiting) effect. Promethazine was first approved by the FDA in 1951. As it's not an H2 blocker type of antihistamine, it does not inhibit gastric acid production like some other types do. Its lack of action on gastric acid means that its side-effect profile is also different to those drugs such as Diclegis, specifically in that it tends to cause sedation and might lead to dry mouth and blurred vision (common side effects of first-generation antihistamines). The calming effect can be beneficial for treating conditions such as allergies or travel sickness, especially in patients who do not respond well to "typical" newer generation antihistamines.
What conditions is Phenergan approved to treat?
Phenergan, a brand name for the drug promethazine, is approved by FDA for various uses including:
- Allergy symptoms such as itching, runny nose and sneezing
- Motion sickness
- Nausea and vomiting related to certain conditions (such as after surgery)
- To help induce sleep in cases of insomnia.
It's important to note that Phenergan should not be used in children under two years due to severe respiratory depression risks. Always consult with your healthcare provider before starting any new medication regimen.
How does Phenergan help with these illnesses?
Phenergan is a medication that plays roles in many processes in the body, including acting as an antihistamine and a sedative. It works by blocking certain effects of histamines produced by the body during allergic reactions or due to motion sickness, thereby alleviating symptoms such as runny nose, itching, sneezing and also preventing nausea and vomiting. Phenergan's action on acetylcholine receptors may contribute to its ability to treat nausea and vomiting. Since it has prominent sedating effects due to its strong anticholinergic properties, it can potentially lead to significant drowsiness compared with Diclegis which is often used specifically for pregnancy-related nausea without causing excessive sleepiness. Therefore, Phenergan might be prescribed when a patient needs not only relief from nausea but also help with insomnia.
How effective are both Diclegis and Phenergan?
Both Diclegis and Phenergan are effective treatments for nausea and vomiting of pregnancy (NVP), with solid histories of use. They were initially approved by the FDA in different eras, with Phenergan dating back to 1951, while Diclegis was reintroduced in its current form in 2013 after withdrawal from the market under a previous name due to non-safety related issues.
Diclegis is specifically indicated for the treatment of NVP when conservative management fails, acting mainly on histamine H1 receptors and muscarinic M1 receptors. It's considered first-line therapy because it lacks known teratogenic risk according to human data. A large randomized controlled trial (RCT) demonstrated that pregnant women who took Diclegis had greater reductions in nausea and vomiting than those taking placebo.
Phenergan has a broader range of indications including allergies, motion sickness, post-operative sedation as well as NVP. Its primary mechanism involves potent antagonism at histamine H1 receptor but also dopaminergic D2 receptors which can lead to potential side effects such as drowsiness or restlessness.
A review published in The Obstetrician & Gynaecologist journal showed that both drugs effectively reduced symptoms of NVP compared with placebo; however, they noted that safety concerns persist regarding antihistamines' association with adverse fetal outcomes (though no definitive causative evidence exists). Nonetheless, given its specific indication and promising safety profile particularly during pregnancy based on available data up until now - Diclegis remains top choice for patients experiencing persistent symptoms despite dietary/lifestyle modifications.
As an older drug often used off-label for NVP – there’s substantial observational data indicating efficacy/safety during pregnancy but less robust RCT evidence supporting Phenergan use against placebos or other medications like Diclegis which could be due to historical times when these rigorous trials weren’t always mandated like today or ethical considerations conducting studies involving pregnant individuals. However anecdotal clinical experiences alongside existing literature still make it a viable alternative especially if first-line options fail/aren’t tolerated plus its beneficial sedating properties where sleep disruption co-exists due to severe nausea/vomiting.
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At what dose is Diclegis typically prescribed?
Oral dosages of Diclegis typically begin with two tablets at bedtime, and if symptoms persist into the afternoon on the following day, an additional tablet may be taken in the morning. If necessary, yet another tablet can be added for mid-afternoon use. The maximum daily dose is four tablets (one in the morning, one in mid-afternoon and two at bedtime). On the other hand, Phenergan dosage varies depending on what it's being used for: to treat allergies or motion sickness a single 25mg dose should suffice; however for nausea and vomiting management during pregnancy - similar to Diclegis indication - it could go up to 50 mg every 4-6 hours as needed. As always consult your doctor before starting any new medication regimen.
At what dose is Phenergan typically prescribed?
Phenergan treatment typically starts at a dosage of 12.5–25 mg/day, which is taken before sleeping or after meals. The dose can then be increased to 50 mg/day, divided into two doses spaced out over the day if needed for severe symptoms. For certain conditions such as allergies or motion sickness, up to 100 mg per day may be prescribed but this should only be under strict medical supervision. As Phenergan can cause drowsiness, it's important that you do not self-adjust your dosage without consulting with your healthcare provider first.
What are the most common side effects for Diclegis?
Common side effects that patients may experience while taking Diclegis include:
- Drowsiness or sleepiness
- Dry mouth, throat, and eyes
- Blurred vision
- Constipation
- Mild dizziness
Conversely, the common side effects of Phenergan can include:
- Confusion (especially in older adults)
- Severe dizziness or fainting
- A dry mouth
- Uncontrollable movements or twitching
- Sleep problems such as insomnia or unusual dreams -Nausea and vomiting
Patients should always consult with their healthcare provider about any concerns they have regarding potential side effects.
Are there any potential serious side effects for Diclegis?
Diclegis and Phenergan are both used to treat nausea and vomiting, but they can have different side effects. Here's what you should watch out for:
- Drowsiness or fatigue which may interfere with your daily activities
- Signs of an allergic reaction such as hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
- Unusual bruising or bleeding
- Increased heart rate or palpitations
- Mental/mood changes (such as hallucinations)
- Blurred vision/dry mouth/constipation
- Decreased coordination
In rare cases, some people might experience:
- Symptoms of a serious liver disease: persistent nausea/vomiting, severe stomach/abdominal pain, dark urine, yellowing eyes/skin
If you notice any of these symptoms after taking Diclegis or Phenergan, contact your healthcare professional immediately.
What are the most common side effects for Phenergan?
Phenergan, also known as Promethazine, may cause some of the following side effects:
-
Dry mouth
-
Drowsiness or listlessness
-
Dizziness and confusion
-
Constipation
-
Blurred vision
-
Ringing in the ears
-
Increased sensitivity to sunlight (photosensitivity)
-
Loss of coordination or balance In rare cases, it can lead to more serious side effects such as:
- Fast/irregular heartbeat
- Mood changes like restlessness, hallucinations or agitation.
Remember always to consult your healthcare provider before making any decisions about your medication.
Are there any potential serious side effects for Phenergan?
While Phenergan is often an effective medication for nausea and vomiting, it can also cause certain serious side effects. These may include:
- Signs of allergic reaction such as hives; difficulty breathing; swelling of your face, lips, tongue or throat.
- Severe dizziness or feeling like you might pass out.
- Twitching or uncontrollable movements of your eyes, lips, tongue, face, arms or legs.
- Unusual bleeding (nosebleeds), increased sweating
- Fainting spells
- Slow heart rate with weak pulse
- Yellowing of the skin or eyes indicating potential liver issues.
If any of these side effects occur while taking Phenergan, cease use immediately and consult your healthcare provider.
Contraindications for Diclegis and Phenergan?
Both Diclegis and Phenergan, along with most other anti-nausea medications, may cause drowsiness in some individuals. If you notice an increase in fatigue or a decrease in alertness that affects your ability to perform daily activities, please consult your healthcare provider immediately.
Neither Diclegis nor Phenergan should be taken if you are currently using or have recently used monoamine oxidase inhibitors (MAOIs). As with all medications, it's essential to inform your doctor about any drugs you're taking; MAOIs will require approximately 5 weeks to clear from the system before starting treatment with either Diclegis or Phenergan to prevent dangerous interactions.
How much do Diclegis and Phenergan cost?
For the brand name versions of these drugs:
- The price of 60 tablets of Diclegis (10 mg/10 mg) averages around $430, which works out to about $14-$28/day, depending on your dose.
- The price for 12.5 mg Phenergan (promethazine), a typical starting dose, ranges from $30-$50 for 30 tablets, equating to approximately $1–$1.65/day.
Thus, if you are taking higher dosages of Diclegis (i.e., up to four tablets per day as recommended by healthcare professionals), then brand-name Phenergan is less expensive on a per-day treatment basis. However, cost should not be the only factor in determining which medication is right for you.
In terms of generic versions:
- Doxylamine-pyridoxine (the generic version of Diclegis) costs significantly less than its branded counterpart with prices ranging from about $0.85 - $2 per tablet.
- Generic promethazine can be even cheaper; it's available in packs ranging from 15 up to several hundred pills and typically costs between $0.20 and $.40/tablet depending upon where you purchase them and how many you buy at once.
Remember that while both medications can help manage symptoms such as nausea or vomiting during pregnancy, they have different active ingredients and side effects profiles that may influence your choice more than cost alone would do so.
Popularity of Diclegis and Phenergan
Diclegis, also known as doxylamine-pyridoxine, is a medication specifically approved for treating nausea and vomiting in pregnancy (NVP), more commonly referred to as morning sickness. In 2020, approximately 1.5 million prescriptions were filled for Diclegis in the US.
Phenergan or promethazine was prescribed around 6 million times in the same year across all indications. It should be noted that Phenergan is not exclusively used for NVP but has a broad range of uses including allergic reactions, sedation purposes, and postoperative nausea/vomiting among others.
While both medications may be utilized to treat NVP, Diclegis carries an FDA category A rating (indicating no risk observed in controlled human studies) making it a preferred option for pregnant women experiencing morning sickness. However, Phenergan has been available longer than Diclegis which might explain its higher prescription volume overall.
Conclusion
Both Diclegis (doxylamine-pyridoxine) and Phenergan (promethazine) have a long-standing record of usage in patients suffering from nausea and vomiting, particularly during pregnancy. They are backed by numerous clinical studies indicating their effectiveness over placebo treatments. While both medications can be used for the same purpose, they act differently within the body. Diclegis functions through a combination of an antihistamine and vitamin B6, whereas Phenergan works primarily as an antihistamine.
Diclegis is often considered a first-line treatment option for morning sickness due to its safety profile in pregnant women, whereas Phenergan may be considered when other treatments fail or aren't tolerated well by the patient.
Both drugs are available in generic form which represents cost savings especially for patients who must pay out-of-pocket. However, it's important to note that while effective relief can sometimes be seen immediately with these medications, other times there might need to be an adjustment period before effects become noticeable.
The side effect profiles are similar between two drugs; drowsiness being one of them. But Phenergan tends to have more potential side effects such as constipation and dry mouth compared to Diclegis. For both drugs, patients should closely monitor their reactions when starting treatment and consult medical help immediately if they notice any severe or persistent adverse symptoms.
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Refrences
- Koren, G., Clark, S., Hankins, G. D. V., Caritis, S. N., Umans, J. G., Miodovnik, M., … Matok, I. (2015, March 18). Maternal safety of the delayed-release doxylamine and pyridoxine combination for nausea and vomiting of pregnancy; a randomized placebo controlled trial. BMC Pregnancy and Childbirth. Springer Science and Business Media LLC.http://doi.org/10.1186/s12884-015-0488-1
- Niebyl, J., & Nuangchamnong, N. (2014, April). Doxylamine succinate–pyridoxine hydrochloride (Diclegis) for the management of nausea and vomiting in pregnancy: an overview. International Journal of Women's Health. Informa UK Limited.http://doi.org/10.2147/ijwh.s46653
- Koren, G., Clark, S., Hankins, G. D. V., Caritis, S. N., Miodovnik, M., Umans, J. G., & Mattison, D. R. (2010, December). Effectiveness of delayed-release doxylamine and pyridoxine for nausea and vomiting of pregnancy: a randomized placebo controlled trial. American Journal of Obstetrics and Gynecology. Elsevier BV.http://doi.org/10.1016/j.ajog.2010.07.030
- Magee, L. A., Mazzotta, P., & Koren, G. (2002, May). Evidence-based view of safety and effectiveness of pharmacologic therapy for nausea and vomiting of pregnancy (NVP). American Journal of Obstetrics and Gynecology. Elsevier BV.http://doi.org/10.1067/mob.2002.122596
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- Persaud, N., Chin, J., & Walker, M. (2014, April). Should Doxylamine-Pyridoxine Be Used for Nausea and Vomiting of Pregnancy?. Journal of Obstetrics and Gynaecology Canada. Elsevier BV.http://doi.org/10.1016/s1701-2163(15)30611-3
- Koren, G., Clark, S., Hankins, G. D. V., Caritis, S. N., Umans, J. G., Miodovnik, M., … Matok, I. (2016, November 24). Demonstration of early efficacy results of the delayed-release combination of doxylamine-pyridoxine for the treatment of nausea and vomiting of pregnancy. BMC Pregnancy and Childbirth. Springer Science and Business Media LLC.http://doi.org/10.1186/s12884-016-1172-9