Histex PD 1.25mg/ml Oral Drops 30ml
It is used to ease allergy signs.
Drug Class
Antihistamine
Pharmacologic Class
First-generation H1-receptor antagonist
Pregnancy Category
Category C
FDA Approved
Jan 1970
DEA Schedule
Not Controlled
Overview
What is this medicine?
Histex PD Oral Drops contain triprolidine, an antihistamine that helps relieve symptoms of allergies and the common cold like sneezing, runny nose, and itchy eyes. It works by blocking a natural substance called histamine that your body makes during an allergic reaction. It can also help dry up nasal secretions.
How to Use This Medicine
Taking Your Medication
To use this medication correctly, follow your doctor's instructions and read all the information provided. You can take this medication with or without food. If it causes stomach upset, taking it with food may help. When measuring liquid doses, use the measuring device that comes with the medication. If one is not provided, ask your pharmacist for a suitable device to ensure accurate measurement.
Storing and Disposing of Your Medication
Store this medication at room temperature in a dry place, avoiding bathrooms. Keep all medications in a safe location, out of the reach of children and pets. Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so. If you have questions about disposal, consult your pharmacist. You may also want to check if there are drug take-back programs in your area.
Missing a Dose
If you take this medication regularly and miss a dose, take it as soon as you remember. However, if it's close to the time for your next dose, skip the missed dose and resume your normal schedule. Do not take two doses at the same time or extra doses. If you take this medication as needed, follow your doctor's instructions and do not take it more frequently than recommended.
To use this medication correctly, follow your doctor's instructions and read all the information provided. You can take this medication with or without food. If it causes stomach upset, taking it with food may help. When measuring liquid doses, use the measuring device that comes with the medication. If one is not provided, ask your pharmacist for a suitable device to ensure accurate measurement.
Storing and Disposing of Your Medication
Store this medication at room temperature in a dry place, avoiding bathrooms. Keep all medications in a safe location, out of the reach of children and pets. Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so. If you have questions about disposal, consult your pharmacist. You may also want to check if there are drug take-back programs in your area.
Missing a Dose
If you take this medication regularly and miss a dose, take it as soon as you remember. However, if it's close to the time for your next dose, skip the missed dose and resume your normal schedule. Do not take two doses at the same time or extra doses. If you take this medication as needed, follow your doctor's instructions and do not take it more frequently than recommended.
Lifestyle & Tips
- Avoid driving or operating heavy machinery until you know how this medication affects you, as it can cause drowsiness.
- Avoid alcohol and other sedating medications, as they can increase drowsiness.
- Drink plenty of fluids to help with dry mouth.
- Do not exceed the recommended dose, especially in children, as it can lead to serious side effects.
Available Forms & Alternatives
Available Strengths:
Dosing & Administration
Adult Dosing
Standard Dose:
2.5 mg (2 ml) every 4-6 hours as needed
Dose Range:
2.5 - 10 mg
Condition-Specific Dosing:
Maximum daily dose:
10 mg (8 ml) in 24 hours
Pediatric Dosing
Neonatal:
Not established; generally not recommended due to risk of respiratory depression and paradoxical excitation.
Infant:
Not established; generally not recommended for infants under 2 years of age without strict medical supervision.
Child:
2 to under 6 years: 0.625 mg (0.5 ml) every 4-6 hours as needed (Max 2.5 mg/2 ml in 24 hours). 6 to under 12 years: 1.25 mg (1 ml) every 4-6 hours as needed (Max 5 mg/4 ml in 24 hours).
Adolescent:
12 years and older: 2.5 mg (2 ml) every 4-6 hours as needed (Max 10 mg/8 ml in 24 hours).
Dose Adjustments
Renal Impairment:
Mild:
No specific adjustment typically required, but monitor for increased sedation.
Moderate:
Consider dose reduction (e.g., 50%) or extended dosing interval (e.g., every 8-12 hours) due to accumulation of metabolites.
Severe:
Significant dose reduction (e.g., 50-75%) or extended dosing interval (e.g., every 12-24 hours) recommended. Avoid if possible.
Dialysis:
Triprolidine is not significantly dialyzable. Administer after dialysis; dose adjustment based on residual renal function.
Hepatic Impairment:
Mild:
No specific adjustment typically required.
Moderate:
Consider dose reduction (e.g., 50%) or extended dosing interval due to impaired metabolism.
Severe:
Significant dose reduction (e.g., 50-75%) or extended dosing interval recommended. Avoid if possible due to extensive hepatic metabolism.
Confidence:
Medium
Pharmacology
Mechanism of Action
Triprolidine is a first-generation alkylamine antihistamine that competitively antagonizes H1-receptors in the periphery and central nervous system. This blocks the effects of histamine, reducing symptoms such as sneezing, rhinorrhea, and itching. It also possesses anticholinergic properties, contributing to its drying effects on nasal secretions and potential for sedation.
Pharmacokinetics
Absorption:
Bioavailability:
High (well absorbed orally)
Tmax:
Approximately 2-3 hours
FoodEffect:
Food may slightly delay absorption but does not significantly affect overall bioavailability.
Distribution:
Vd:
Approximately 2.5-4 L/kg
ProteinBinding:
Approximately 80%
CnssPenetration:
Yes (readily crosses the blood-brain barrier, contributing to sedative effects)
Elimination:
HalfLife:
Approximately 3-5 hours (can vary)
Clearance:
Not precisely quantified, but primarily hepatic metabolism followed by renal excretion.
ExcretionRoute:
Primarily renal (as metabolites)
Unchanged:
<1% (very little unchanged drug excreted)
Pharmacodynamics
OnsetOfAction:
Within 15-30 minutes
PeakEffect:
Approximately 1-2 hours
DurationOfAction:
4-6 hours
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
If you experience any of the following symptoms, call your doctor immediately or seek emergency medical attention, as they may be signs of a severe and potentially life-threatening reaction:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Other Possible Side Effects
While most people may not experience any side effects or only mild ones, it's essential to be aware of the following:
Feeling sleepy
Feeling nervous and excitable
If you're bothered by these or any other side effects, or if they don't go away, contact your doctor for advice. Not all possible side effects are listed here. If you have questions or concerns, don't hesitate to reach out to your doctor.
Reporting Side Effects
To report side effects, you can:
Call the FDA at 1-800-332-1088
* Visit the FDA's MedWatch website at https://www.fda.gov/medwatch to submit a report. Your doctor can also provide guidance on reporting side effects.
If you experience any of the following symptoms, call your doctor immediately or seek emergency medical attention, as they may be signs of a severe and potentially life-threatening reaction:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Other Possible Side Effects
While most people may not experience any side effects or only mild ones, it's essential to be aware of the following:
Feeling sleepy
Feeling nervous and excitable
If you're bothered by these or any other side effects, or if they don't go away, contact your doctor for advice. Not all possible side effects are listed here. If you have questions or concerns, don't hesitate to reach out to your doctor.
Reporting Side Effects
To report side effects, you can:
Call the FDA at 1-800-332-1088
* Visit the FDA's MedWatch website at https://www.fda.gov/medwatch to submit a report. Your doctor can also provide guidance on reporting side effects.
Seek Immediate Medical Attention If You Experience:
- Severe drowsiness or dizziness
- Difficulty urinating
- Blurred vision
- Confusion or hallucinations (especially in children or elderly)
- Fast or irregular heartbeat
- Difficulty breathing or swallowing
- Seizures
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction you experienced, including any symptoms that occurred.
All medications you are currently taking, including prescription and over-the-counter (OTC) drugs, natural products, and vitamins. This is crucial to avoid potential interactions between this medication and other substances.
* Any existing health problems you have, as they may affect the safety and efficacy of this medication.
To ensure your safety, it is vital to verify that it is safe to take this medication with all your other medications and health conditions. Never start, stop, or change the dose of any medication without first consulting your doctor. Always consult with your doctor and pharmacist to confirm that it is safe to take this medication in conjunction with your other medications and health conditions.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction you experienced, including any symptoms that occurred.
All medications you are currently taking, including prescription and over-the-counter (OTC) drugs, natural products, and vitamins. This is crucial to avoid potential interactions between this medication and other substances.
* Any existing health problems you have, as they may affect the safety and efficacy of this medication.
To ensure your safety, it is vital to verify that it is safe to take this medication with all your other medications and health conditions. Never start, stop, or change the dose of any medication without first consulting your doctor. Always consult with your doctor and pharmacist to confirm that it is safe to take this medication in conjunction with your other medications and health conditions.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. To minimize the risk of severe side effects, do not exceed the dosage prescribed by your doctor. Adhering to the recommended treatment duration is also crucial; do not take this drug for longer than specified by your doctor.
Until you understand how this medication affects you, it is advisable to avoid operating a vehicle and engaging in activities that require alertness. Additionally, refrain from consuming alcohol while taking this drug, as it may exacerbate its effects.
Before using marijuana, other cannabis products, or prescription and over-the-counter (OTC) medications that can cause drowsiness or impair your reactions, consult with your doctor to discuss potential interactions.
When administering this drug to children, exercise caution, as they may be at a higher risk of experiencing excitability.
If you are pregnant, planning to become pregnant, or are breast-feeding, inform your doctor. It is crucial to discuss the potential benefits and risks of this medication to both you and your baby to make an informed decision.
Until you understand how this medication affects you, it is advisable to avoid operating a vehicle and engaging in activities that require alertness. Additionally, refrain from consuming alcohol while taking this drug, as it may exacerbate its effects.
Before using marijuana, other cannabis products, or prescription and over-the-counter (OTC) medications that can cause drowsiness or impair your reactions, consult with your doctor to discuss potential interactions.
When administering this drug to children, exercise caution, as they may be at a higher risk of experiencing excitability.
If you are pregnant, planning to become pregnant, or are breast-feeding, inform your doctor. It is crucial to discuss the potential benefits and risks of this medication to both you and your baby to make an informed decision.
Overdose Information
Overdose Symptoms:
- Severe drowsiness or sedation
- Dizziness
- Ataxia (loss of coordination)
- Dry mouth and skin
- Flushing
- Dilated pupils
- Fever
- Hallucinations
- Seizures
- Coma
- Respiratory depression
- Cardiovascular collapse
What to Do:
Seek immediate medical attention. Call 911 or Poison Control at 1-800-222-1222. Treatment is supportive and symptomatic, including gastric lavage, activated charcoal, and maintaining vital signs.
Drug Interactions
Contraindicated Interactions
- Monoamine Oxidase Inhibitors (MAOIs) concurrently or within 14 days of use (risk of hypertensive crisis, severe anticholinergic effects)
Major Interactions
- CNS depressants (e.g., alcohol, opioids, benzodiazepines, sedatives, hypnotics, tricyclic antidepressants): Increased sedation and CNS depression.
- Other anticholinergic drugs (e.g., atropine, scopolamine, some antipsychotics, tricyclic antidepressants): Increased risk of anticholinergic side effects (dry mouth, urinary retention, blurred vision, constipation).
Moderate Interactions
- Potassium chloride (oral forms): Increased risk of GI lesions due to slowed GI motility.
- Betahistine: May reduce the effect of betahistine (histamine analog).
Minor Interactions
- Topical anesthetics (e.g., pramoxine): May have additive local anesthetic effects.
Monitoring
Baseline Monitoring
Patient history (allergies, pre-existing conditions like glaucoma, prostatic hypertrophy, asthma)
Rationale: To identify contraindications or conditions where caution is needed due to anticholinergic effects or respiratory depression risk.
Timing: Prior to initiation of therapy
Routine Monitoring
Symptom relief (e.g., sneezing, rhinorrhea, itching)
Frequency: Daily, as needed
Target: Reduction or resolution of allergic symptoms
Action Threshold: Lack of efficacy after appropriate trial, consider alternative therapy.
Sedation/Drowsiness
Frequency: Daily, as needed
Target: Minimal or tolerable sedation
Action Threshold: Excessive drowsiness, impaired cognitive function, or interference with daily activities; consider dose reduction or alternative.
Anticholinergic side effects (e.g., dry mouth, blurred vision, urinary retention, constipation)
Frequency: Daily, as needed
Target: Absence or mild, tolerable symptoms
Action Threshold: Severe or bothersome symptoms; consider dose reduction or alternative.
Symptom Monitoring
- Drowsiness
- Dizziness
- Dry mouth
- Blurred vision
- Urinary retention
- Constipation
- Nervousness
- Excitability (paradoxical reaction, especially in children)
- Difficulty breathing (rare, severe reaction)
Special Patient Groups
Pregnancy
Triprolidine is Pregnancy Category C. It should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Studies in animals have shown adverse effects, but there are no adequate and well-controlled studies in pregnant women.
Trimester-Specific Risks:
First Trimester:
Limited data; potential for increased risk of congenital malformations not definitively established but caution advised.
Second Trimester:
Generally considered safer than first trimester, but still use with caution.
Third Trimester:
Use with caution, especially near term, due to potential for neonatal effects (e.g., irritability, tremors, respiratory depression) from anticholinergic properties.
Lactation
Triprolidine is excreted into breast milk. It is rated L3 (Moderately Safe) by Hale's classification. While generally considered compatible with breastfeeding, caution is advised due to potential for infant sedation, irritability, or paradoxical excitation, and theoretical risk of decreased milk supply due to anticholinergic effects.
Infant Risk:
Moderate risk of sedation, irritability, or paradoxical excitation in the infant. Monitor infant for drowsiness, poor feeding, or unusual excitability. Use lowest effective dose and avoid prolonged use.
Pediatric Use
First-generation antihistamines like triprolidine are generally not recommended for infants under 2 years of age due to increased risk of respiratory depression, paradoxical excitation, and other serious adverse effects. Use in children 2-6 years should be with caution and under medical guidance. Always use the appropriate pediatric formulation and dosing based on age/weight. Overdose in children can be fatal.
Geriatric Use
Elderly patients are more susceptible to the sedative and anticholinergic side effects (e.g., dry mouth, urinary retention, constipation, confusion, dizziness) of triprolidine. Use with caution, starting with the lowest effective dose and monitoring closely for adverse effects. Avoid in elderly patients with conditions exacerbated by anticholinergic effects (e.g., glaucoma, prostatic hypertrophy, dementia).
Clinical Information
Clinical Pearls
- Triprolidine is a first-generation antihistamine known for its significant sedative and anticholinergic effects. Counsel patients about these side effects.
- Due to its sedative properties, it can be useful for nighttime symptom relief, but caution against driving or operating machinery.
- Avoid concomitant use with alcohol or other CNS depressants to prevent excessive sedation.
- In pediatric patients, especially those under 2 years, use with extreme caution or avoid due to the risk of respiratory depression and paradoxical excitation.
- Advise patients to stay hydrated to help manage dry mouth.
- This formulation (oral drops) is specifically designed for precise pediatric dosing; ensure caregivers use the provided measuring device accurately.
Alternative Therapies
- Second-generation antihistamines (e.g., loratadine, cetirizine, fexofenadine) for less sedation and anticholinergic effects.
- Intranasal corticosteroids (e.g., fluticasone, mometasone) for allergic rhinitis.
- Nasal saline rinses for symptomatic relief.
- Cromolyn sodium nasal spray (mast cell stabilizer).
Cost & Coverage
Average Cost:
Varies, typically low per 30ml bottle
Generic Available:
Yes
Insurance Coverage:
Tier 1 or Tier 2 (preferred generic)
General Drug Facts
If your symptoms or health condition do not improve or worsen over time, it is essential to contact your doctor for further evaluation and guidance.
To ensure your safety and the effectiveness of your treatment, never share your medication with others or take medication that has been prescribed to someone else.
You may receive additional patient information leaflets for certain medications. If you have any questions or concerns, consult with your pharmacist to obtain more information.
If you have any questions or concerns about your medication, do not hesitate to discuss them with your doctor, nurse, pharmacist, or other healthcare provider. They can provide you with personalized guidance and support.
In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When reporting the incident, be prepared to provide detailed information about the overdose, including the name of the medication taken, the amount consumed, and the time it occurred.
To ensure your safety and the effectiveness of your treatment, never share your medication with others or take medication that has been prescribed to someone else.
You may receive additional patient information leaflets for certain medications. If you have any questions or concerns, consult with your pharmacist to obtain more information.
If you have any questions or concerns about your medication, do not hesitate to discuss them with your doctor, nurse, pharmacist, or other healthcare provider. They can provide you with personalized guidance and support.
In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When reporting the incident, be prepared to provide detailed information about the overdose, including the name of the medication taken, the amount consumed, and the time it occurred.