Carbinoxamine maleate, also known by its brand name Ryvent, is a prescription antihistamine used to treat many symptoms of allergies and allergic reactions, such as rash, hives, itching, and sneezing. It's FDA approved for adults and children ages 2 years and older. It comes as a tablet and liquid that are taken by mouth up to 4 times per day on an empty stomach. Side effects include sleepiness, dizziness, and stomach pain.
Eye inflammation from airborne allergens or food
Mild skin symptoms of hives and angioedema
Dermatographism (condition with raised welts or hives caused by light scratching or pressure)
Severe allergic reaction when used together with epinephrine
Allergic reactions to blood or plasma products
Carbinoxamine is an antihistamine. It blocks a natural chemical in your body called histamine, which is responsible for many allergy symptoms. By blocking histamine in your stomach, blood vessels, and lungs, it helps relieve symptoms like itching, sneezing, and rash.
Source: DailyMed
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
Incidence not known
Blurred vision
chills
confusion
decrease in the frequency of urination
decrease in urine volume
difficult or painful urination
difficulty in passing urine (dribbling)
difficulty with swallowing
dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
fast, irregular, pounding, or racing heartbeat or pulse
hives or welts, itching, skin rash
puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
redness of the skin
sweating
tightness in the chest
unusual tiredness or weakness
Get emergency help immediately if any of the following symptoms of overdose occur:
Symptoms of overdose
Agitation
difficulty with sleeping
disorientation
dizziness
drowsiness to profound coma
feeling of warmth
fixed and enlarged pupils
headache
lethargy
lightheadedness
loss of appetite
redness of the face, neck, arms, and occasionally, upper chest
seeing, hearing, or feeling things that are not there
seizures
tightness of the chest
trouble breathing
vomiting
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
Incidence not known
Back, leg, or stomach pains
black, tarry stools
bleeding gums
blood in the urine or stools
blurred vision
burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
chills
confusion
continuing ringing or buzzing or other unexplained noise in the ears
cough or hoarseness
dark urine
difficulty breathing
difficulty having a bowel movement (stool)
dizziness or lightheadedness
double vision
dry mouth, nose, and throat
feeling excited
feeling of constant movement of self or surroundings
fever with or without chills
general body swelling
general feeling of tiredness or weakness
headache
hearing loss
increased sensitivity of the skin to sunlight
loss of appetite
lower back or side pain
nosebleeds
pale skin
pinpoint red spots on the skin
redness or other discoloration of the skin
restlessness
seeing double
seizures
sensation of spinning
severe sunburn
shakiness in the legs, arms, hands, or feet
sores, ulcers, or white spots on the lips or in the mouth
trembling or shaking of the hands or feet
trouble sleeping
unusual bleeding or bruising
yellowing of the eyes or skin
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Treats many symptoms of allergies and allergic reactions
Comes as tablets and a flavored liquid
Safe for children as young as 2 years old
Can be taken as needed or on a regular schedule, depending on your condition
Need to take 3 to 4 times per day
Commonly causes sleepiness and dizziness
Interacts with many medications
Can worsen certain medical conditions including glaucoma, stomach ulcers, and urinary problems
Take carbinoxamine with or without food, but it's best if you take it on an empty stomach with a full glass of water.
Carbinoxamine can be taken as needed. But if you have symptoms on a daily basis, taking it regularly might give you the most relief. Ask your prescriber about the best way for you to take this medication.
For the liquid: Store carbinoxamine liquid at room temperature. Use a medication dosing cup or oral syringe to measure the dose. If you need one, ask your pharmacy. Avoid household spoons because they might not be accurate and could lead you to take the wrong dose.
Carbinoxamine can make you sleepy, dizzy, and lose your balance. Don't drive until you know how this medication affects you. Also, avoid drinking alcohol because it can worsen these side effects.
Carbinoxamine can interact with other medications, such as tricyclic antidepressants, monoamine oxidase inhibitors (MAOIs), and other medications that make you sleepy. Tell your prescriber about all the medications you take before starting carbinoxamine.
Avoid taking other antihistamines while taking carbinoxamine. Many over-the-counter (OTC) products contain antihistamines, and taking more than one can raise your risk of antihistamine overdose, which can lead to serious side effects like heart problems, seizures, or even death.
Carbinoxamine isn't recommended while breastfeeding because it can cause serious harm to children under 2 years old. Let your prescriber know if you're breastfeeding. They can help figure out a safer alternative for you to use.
Store carbinoxamine up and away from children and pets. That way, they're less likely to reach it and accidentally take the medication. If you think your child accidentally took the medication, call a Poison Control Center right away at 1-800-222-1222.
Carbinoxamine can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Risk factors: Children under 2 years old
Children under 2 years old should never take carbinoxamine since deaths have been reported in this age group. So keeping this medication away from young children is very important for their safety. It's also important to avoid breastfeeding since the medication likely passes into breastmilk which can cause serious harm to young children. If your child under 2 accidentally takes the medication, call a Poison Control Center right away at 1-800-222-1222. For children under age 2, discuss safer treatment options with your child's pediatrician.
Risk factors: Alcohol | Taking other medications that cause sleepiness | Older adults
Carbinoxamine can make you sleepy, which can affect your ability to focus, think, or react. This side effect is more likely to happen or be more intense if you're an older adult, drink alcohol while taking carbinoxamine, or take other medications that cause sleepiness (e.g., opioids, benzodiazepines). Don't drive or operate machinery until you know how this medication affects you. It's best to avoid alcohol while taking carbinoxamine. Talk to your prescriber about possible interactions with other medications and how to manage them.
Make sure your care team knows about all of your medical conditions before starting carbinoxamine. Though this medication is an antihistamine, it also has anticholinergic effects, which can worsen the symptoms of many conditions. These conditions include glaucoma, hyperthyroidism, heart disease, high blood pressure, stomach ulcers, trouble urinating, and an enlarged prostate.
Carbinoxamine tablet:
People ages 12 years and older: The typical dose is 4 mg to 8 mg by mouth three to four times per day on an empty stomach.
Children ages 6 to 11 years: The typical dose is 2 mg to 4 mg by mouth three to four times per day on an empty stomach.
Carbinoxamine liquid:
People ages 12 years and older: The typical dose is 1 or 2 teaspoonfuls (4 mg to 8 mg) by mouth three to four times per day on an empty stomach.
Children ages 6 to 11 years: The typical dose is ½ to 1 teaspoonful (2 mg to 4 mg) by mouth three to four times per day on an empty stomach.
Children ages 2 to 5 years: The typical dose is ¼ to ½ teaspoonful (1 mg to 2 mg) by mouth three to four times per day on an empty stomach.
Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Children under age 2
Currently breastfeeding
Taking a monoamine oxidase inhibitor (MAOIs), such as phenelzine (Nardil), tranylcypromine (Parnate), and selegiline (Eldepryl)
Eye inflammation from airborne allergens or food
Mild skin symptoms of hives and angioedema
Dermatographism (condition with raised welts or hives caused by light scratching or pressure)
Severe allergic reaction when used together with epinephrine
Allergic reactions to blood or plasma products
Allergies
Common cold symptoms
Trouble sleeping for people 12 years and older
Short-term relief of allergy symptoms (runny nose, itchy nose, itchy or watery eyes)
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American Osteopathic College of Dermatology. (n.d). Dermatographism.
Borowy, C. S., et al. (2023). Antihistamine toxicity. StatPearls.
Centers for Disease Control and Prevention. (n.d.). PROTECT your child: Use the right tool to give the right dose.
Drugs and Lactation Database (LactMed®). (2021). Carboximine. National Institute of Child Health and Human Development.
Genus LIfesciences Inc. (2024). Carbinoxamine maleate solution; Carbinosamine maleate tablet [package insert]. DailyMed.
Leader, P., et al. (2023). Vasomotor rhinitis. StatPearls.
MedlinePlus. (2024). Angioedema.
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