Orphenadrine 30mg/ml Inj, 2ml
It is used to relax muscles.
Drug Class
Skeletal Muscle Relaxant
Pharmacologic Class
Anticholinergic, Antihistamine
Pregnancy Category
Category C
FDA Approved
Jul 1959
DEA Schedule
Not Controlled
Overview
What is this medicine?
Orphenadrine injection is a medicine used to help relax muscles and relieve pain and stiffness caused by muscle injuries or strains. It works by affecting the brain and nervous system, rather than directly on the muscles.
How to Use This Medicine
To use this medication correctly, follow your doctor's instructions and carefully read all accompanying information. Take this medication exactly as directed, and adhere to all guidelines provided. This medication is administered via injection into a muscle or vein.
For proper storage and disposal, consult with your doctor, nurse, or pharmacist to determine the best approach if you need to store this medication at home.
If you miss a dose, contact your doctor immediately to receive guidance on the appropriate course of action.
For proper storage and disposal, consult with your doctor, nurse, or pharmacist to determine the best approach if you need to store this medication at home.
If you miss a dose, contact your doctor immediately to receive guidance on the appropriate course of action.
Lifestyle & Tips
- Avoid driving or operating heavy machinery until you know how this medication affects you, as it can cause drowsiness or dizziness.
- Avoid alcohol consumption while taking this medication, as it can increase drowsiness and other side effects.
- Avoid other medications that cause drowsiness without consulting your doctor or pharmacist.
- Stay hydrated to help manage dry mouth, a common side effect.
Available Forms & Alternatives
Available Strengths:
Dosing & Administration
Adult Dosing
Standard Dose:
60 mg (2 mL) intramuscularly or intravenously every 12 hours as needed.
Dose Range:
60 - 120 mg
Condition-Specific Dosing:
acuteMusculoskeletalConditions:
60 mg (2 mL) IM or IV every 12 hours.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Not established (Contraindicated in children under 12 years of age)
Adolescent:
Not established (Contraindicated in children under 12 years of age)
Dose Adjustments
Renal Impairment:
Mild:
Use with caution; monitor for adverse effects.
Moderate:
Use with caution; consider dose reduction and monitor for adverse effects.
Severe:
Use with caution; consider significant dose reduction and monitor closely for adverse effects. Specific guidelines not available.
Dialysis:
Not available; likely not dialyzable due to high volume of distribution and metabolism.
Hepatic Impairment:
Mild:
Use with caution; monitor for adverse effects.
Moderate:
Use with caution; consider dose reduction and monitor for adverse effects. Specific guidelines not available.
Severe:
Use with caution; consider significant dose reduction and monitor closely for adverse effects. Specific guidelines not available.
Pharmacology
Mechanism of Action
Orphenadrine is a centrally acting skeletal muscle relaxant. Its exact mechanism of action is not fully understood but is believed to be related to its analgesic and anticholinergic properties. It does not directly relax tense muscles but may act by blocking nerve impulses (pain sensations) to the brain. It also possesses antihistaminic and local anesthetic properties.
Pharmacokinetics
Absorption:
Bioavailability:
Not explicitly quantified for IM, but well absorbed.
Tmax:
1-2 hours (IM)
FoodEffect:
Not applicable for injection.
Distribution:
Vd:
Large (e.g., 100-200 L)
ProteinBinding:
Approximately 20%
CnssPenetration:
Yes
Elimination:
HalfLife:
14-16 hours (range 8-24 hours)
Clearance:
Not precisely quantified, but extensive hepatic metabolism.
ExcretionRoute:
Primarily renal (urine) as metabolites, some fecal excretion.
Unchanged:
<8% (in urine)
Pharmacodynamics
OnsetOfAction:
Within minutes (IM/IV)
PeakEffect:
1-2 hours (IM)
DurationOfAction:
4-6 hours (primary effect), up to 12 hours (dosing interval)
Safety & Warnings
Side Effects
Serious Side Effects: Seek Medical Help Immediately
Although rare, this medication can cause severe and potentially life-threatening side effects. If you experience any of the following symptoms, contact your doctor or seek medical attention right away:
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
Severe dizziness or fainting
Confusion
Anxiety
Abnormal or rapid heartbeat
Changes in vision, eye pain, or severe eye irritation
Difficulty urinating
Hallucinations (seeing or hearing things that are not there)
Shakiness
Agitation
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other unusual symptoms that bother you or do not go away, contact your doctor:
Upset stomach or vomiting
Dry mouth
Dizziness, drowsiness, tiredness, or weakness
Headache
* Constipation
Reporting Side Effects
This list is not exhaustive, and you may experience other side effects. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Although rare, this medication can cause severe and potentially life-threatening side effects. If you experience any of the following symptoms, contact your doctor or seek medical attention right away:
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
Severe dizziness or fainting
Confusion
Anxiety
Abnormal or rapid heartbeat
Changes in vision, eye pain, or severe eye irritation
Difficulty urinating
Hallucinations (seeing or hearing things that are not there)
Shakiness
Agitation
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other unusual symptoms that bother you or do not go away, contact your doctor:
Upset stomach or vomiting
Dry mouth
Dizziness, drowsiness, tiredness, or weakness
Headache
* Constipation
Reporting Side Effects
This list is not exhaustive, and you may experience other side effects. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Severe dizziness or fainting
- Extreme drowsiness or confusion
- Hallucinations (seeing or hearing things that are not there)
- Difficulty urinating or inability to urinate
- Severe dry mouth or eyes
- Blurred vision or eye pain
- Fast or irregular heartbeat
- Rash, itching, or swelling (especially of the face, tongue, or throat)
- Difficulty breathing
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.
Certain health conditions, including:
+ Enlarged prostate gland
+ Glaucoma
+ Bowel blockage
+ Myasthenia gravis
+ Ulcer disease
+ Difficulty urinating
+ Difficulty swallowing
Please note that this is not an exhaustive list of all potential interactions with this medication. To ensure your safety, it is crucial to discuss all of your:
Medications, including prescription and over-the-counter drugs, natural products, and vitamins
Health problems
with your doctor and pharmacist. They will help determine whether it is safe for you to take this medication in combination with your other medications and health conditions. Never start, stop, or change the dose of any medication without first consulting 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.
Certain health conditions, including:
+ Enlarged prostate gland
+ Glaucoma
+ Bowel blockage
+ Myasthenia gravis
+ Ulcer disease
+ Difficulty urinating
+ Difficulty swallowing
Please note that this is not an exhaustive list of all potential interactions with this medication. To ensure your safety, it is crucial to discuss all of your:
Medications, including prescription and over-the-counter drugs, natural products, and vitamins
Health problems
with your doctor and pharmacist. They will help determine whether it is safe for you to take this medication in combination with your other medications and health conditions. Never start, stop, or change the dose of any medication without first consulting your doctor.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication.
To ensure your safety, avoid driving and engaging in activities that require alertness until you understand how this medication affects you. If you are taking this medication long-term, your doctor may recommend regular blood tests to monitor your condition.
Before consuming alcohol, using marijuana or other cannabis products, or taking prescription or over-the-counter medications that can cause drowsiness, consult with your doctor to discuss potential interactions.
This medication is often used in conjunction with rest, physical therapy, pain management medications, and other therapies to achieve optimal results.
If you have a known allergy to sulfites, inform your doctor, as some formulations of this medication may contain sulfites. Additionally, if you are 65 years or older, use this medication with caution, as you may be more susceptible to side effects.
If you are pregnant, planning to become pregnant, or breastfeeding, consult with your doctor to discuss the potential benefits and risks of this medication to both you and your baby.
To ensure your safety, avoid driving and engaging in activities that require alertness until you understand how this medication affects you. If you are taking this medication long-term, your doctor may recommend regular blood tests to monitor your condition.
Before consuming alcohol, using marijuana or other cannabis products, or taking prescription or over-the-counter medications that can cause drowsiness, consult with your doctor to discuss potential interactions.
This medication is often used in conjunction with rest, physical therapy, pain management medications, and other therapies to achieve optimal results.
If you have a known allergy to sulfites, inform your doctor, as some formulations of this medication may contain sulfites. Additionally, if you are 65 years or older, use this medication with caution, as you may be more susceptible to side effects.
If you are pregnant, planning to become pregnant, or breastfeeding, consult with your doctor to discuss the potential benefits and risks of this medication to both you and your baby.
Overdose Information
Overdose Symptoms:
- Severe drowsiness or coma
- Respiratory depression (slow, shallow breathing)
- Seizures
- Severe anticholinergic effects (e.g., dilated pupils, blurred vision, dry mucous membranes, flushed skin, hyperthermia, urinary retention, absent bowel sounds)
- Tachycardia or arrhythmias
- Hypotension
- Agitation, delirium, hallucinations
What to Do:
Seek immediate medical attention. Call 911 or your local emergency number. For poison control, call 1-800-222-1222. Treatment is supportive and symptomatic. Physostigmine may be considered for severe anticholinergic toxicity.
Drug Interactions
Contraindicated Interactions
- Patients with glaucoma
- Patients with myasthenia gravis
- Patients with prostatic hypertrophy or bladder neck obstruction
- Patients with pyloric or duodenal obstruction
- Patients with stenosing peptic ulcer
- Patients with cardiospasm (megaesophagus)
- Patients with megacolon
Major Interactions
- CNS depressants (e.g., alcohol, opioids, benzodiazepines, sedatives, hypnotics): Increased CNS depression.
- Other anticholinergic drugs (e.g., tricyclic antidepressants, antihistamines, phenothiazines): Potentiation of anticholinergic effects (e.g., dry mouth, blurred vision, urinary retention, constipation).
- Monoamine Oxidase Inhibitors (MAOIs): May prolong and intensify the anticholinergic effects of orphenadrine.
Moderate Interactions
- Not available
Minor Interactions
- Not available
Monitoring
Baseline Monitoring
Assessment of pain and muscle spasm severity
Rationale: To establish baseline for therapeutic efficacy evaluation.
Timing: Prior to initiation of therapy.
Vital signs (heart rate, blood pressure)
Rationale: To identify baseline and monitor for anticholinergic effects (tachycardia) or orthostatic hypotension.
Timing: Prior to initiation of therapy.
Patient history for contraindications (e.g., glaucoma, urinary retention, GI obstruction)
Rationale: To ensure safe use and avoid adverse events.
Timing: Prior to initiation of therapy.
Routine Monitoring
Therapeutic efficacy (reduction in pain/spasm)
Frequency: Daily or as clinically indicated during acute treatment.
Target: Subjective improvement in symptoms.
Action Threshold: Lack of improvement or worsening symptoms may indicate need for alternative therapy or re-evaluation.
Adverse effects (e.g., drowsiness, dry mouth, blurred vision, urinary retention, confusion, tachycardia)
Frequency: Regularly during therapy, especially during initial days.
Target: Absence or mild, tolerable side effects.
Action Threshold: Development of severe or intolerable side effects requires dose adjustment or discontinuation.
Mental status (especially in elderly)
Frequency: Daily or as clinically indicated.
Target: Normal cognitive function.
Action Threshold: New onset or worsening confusion, disorientation, or hallucinations.
Symptom Monitoring
- Drowsiness
- Dizziness
- Dry mouth
- Blurred vision
- Nausea
- Vomiting
- Lightheadedness
- Urinary hesitancy or retention
- Constipation
- Tachycardia
- Palpitations
- Weakness
- Confusion
- Hallucinations
Special Patient Groups
Pregnancy
Orphenadrine is classified as Pregnancy Category C. It should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Animal studies have shown adverse effects, but there are no adequate and well-controlled studies in pregnant women.
Trimester-Specific Risks:
First Trimester:
Potential for fetal harm based on animal data; use only if clearly needed.
Second Trimester:
Potential for fetal harm based on animal data; use only if clearly needed.
Third Trimester:
Potential for fetal harm based on animal data; use only if clearly needed. Anticholinergic effects could theoretically affect the fetus or neonate.
Lactation
Orphenadrine is rated L4 (Possibly Hazardous) for lactation. No human data are available on the presence of orphenadrine in human milk, its effects on the breastfed infant, or its effects on milk production. Due to its long half-life and anticholinergic effects, other agents may be preferred, especially while nursing a newborn or preterm infant. Monitor the infant for drowsiness, feeding difficulties, and anticholinergic effects.
Infant Risk:
Moderate to high risk; potential for drowsiness, anticholinergic effects (e.g., dry mouth, constipation), and feeding difficulties in the infant.
Pediatric Use
Safety and efficacy have not been established in pediatric patients. Orphenadrine is contraindicated in children under 12 years of age.
Geriatric Use
Elderly patients are more susceptible to the anticholinergic side effects of orphenadrine, such as confusion, hallucinations, urinary retention, constipation, and orthostatic hypotension. Use with caution, start with lower doses, and monitor closely for adverse effects. Consider Beers Criteria for potentially inappropriate medication use in older adults.
Clinical Information
Clinical Pearls
- Orphenadrine is typically used for short-term relief of acute, painful musculoskeletal conditions.
- It is not a direct muscle relaxant; its effects are primarily due to its central anticholinergic and analgesic properties.
- Patients should be warned about potential for drowsiness and dizziness, and advised to avoid activities requiring mental alertness.
- Due to its anticholinergic properties, it should be used with extreme caution or avoided in patients with conditions exacerbated by anticholinergic effects (e.g., glaucoma, prostatic hypertrophy).
- Intravenous administration should be performed slowly to minimize the risk of adverse reactions.
Alternative Therapies
- Other centrally acting skeletal muscle relaxants (e.g., cyclobenzaprine, methocarbamol, tizanidine, baclofen, carisoprodol, metaxalone)
- Nonsteroidal anti-inflammatory drugs (NSAIDs)
- Acetaminophen
- Physical therapy
- Heat/cold therapy
Cost & Coverage
Average Cost:
Variable, typically low per 2mL vial
Generic Available:
Yes
Insurance Coverage:
Tier 1 or 2 (Generic)
General Drug Facts
If your symptoms or health problems persist or worsen, it is essential to contact your doctor for further guidance. To ensure safe use, never share your medication with others, and do not take medication prescribed for someone else. Store all medications in a secure location, out of reach of children and pets, to prevent accidental ingestion. Dispose of unused or expired medications properly. Unless instructed otherwise, do not flush medications down the toilet or pour them down the drain. If you are unsure about the proper disposal method, consult your pharmacist, who can also inform you about potential drug take-back programs in your area. Some medications may come with an additional patient information leaflet, which your pharmacist can provide. If you have any questions or concerns about your medication, discuss them with your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately contact your local poison control center or seek medical attention. Be prepared to provide information about the medication taken, the amount, and the time it happened, as this will aid in receiving appropriate treatment.