Medically reviewed by Drugs.com. Last updated on Apr 20, 2022.
The Antiflex brand name has been discontinued in the U.S. If generic versions of this product have been approved by the FDA, there may be generic equivalents available.
Commonly used brand name(s)
In the U.S.
Available Dosage Forms:
Therapeutic Class: Skeletal Muscle Relaxant, Centrally Acting
Pharmacologic Class: Antimuscarinic
Uses for Antiflex
Orphenadrine is used to help relax certain muscles in your body and relieve the stiffness, pain, and discomfort caused by strains, sprains, or other injury to your muscles. However, this medicine does not take the place of rest, exercise or physical therapy, or other treatment that your doctor may recommend for your medical problem .
Orphenadrine acts in the central nervous system (CNS) to produce its muscle relaxant effects .
This medicine is available only with your doctor's prescription .
Before using Antiflex
In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:
The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.
The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.
Appropriate studies have not been performed on the relationship of age to the effects of orphenadrine in the pediatric population. Safety and efficacy have not been established .
No information is available on the relationship of age to the effects of orphenadrine in geriatric patients. However, elderly patients are more likely to have age-related heart, liver, or kidney problems which may require caution in patients receiving orphenadrine .
There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.
Interactions with medicines
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are receiving this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
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.
- Potassium Citrate
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.
- Calcium Oxybate
- Gabapentin Enacarbil
- Glycopyrronium Tosylate
- Magnesium Oxybate
- Morphine Sulfate Liposome
- Potassium Oxybate
- Ropeginterferon Alfa-2b-njft
- Secretin Human
- Sodium Oxybate
Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Interactions with food/tobacco/alcohol
Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.
Other medical problems
The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:
- Enlarged esophagus or
- Enlarged prostate or
- Glaucoma or
- Intestinal blockage or
- Myasthenia gravis or
- Stomach ulcer or
- Urinary tract blockage—Orphenadrine should not be used in patients with these conditions .
- Heart problems (e.g., fast or irregular heartbeats, heart failure)—Use with caution. Orphenadrine may worsen these conditions .
Proper use of Antiflex
This section provides information on the proper use of a number of products that contain orphenadrine. It may not be specific to Antiflex. Please read with care.
A nurse or other trained health professional will give you this medicine. This medicine is given through a needle placed in one of your veins or into your muscle .
Precautions while using Antiflex
Your doctor will only give you a few doses of this medicine until your condition improves, and then you will be switched to an oral medicine that works the same way. If you have any concerns about this, talk to your doctor .
Antiflex side effects
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 or nurse immediately if any of the following side effects occur:
- difficulty swallowing
- fast heartbeat
- puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
- shortness of breath
- skin rash
- tightness in chest
- unusual tiredness or weakness
Incidence not known
- Abdominal or stomach pain
- fast, pounding, or irregular heartbeat or pulse
- joint or muscle pain
- numbness or tingling of face, hands, or feet
- redness and soreness of eyes
- shortness of breath
- sores in mouth
- swelling of feet or lower legs
Get emergency help immediately if any of the following symptoms of overdose occur:
Symptoms of Overdose
- Blurred vision
- confusion, delirium, or hallucinations
- difficult urination
- dry eyes, mouth, nose, or throat
- eye pain
- flushing or redness of face
- troubled breathing
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
- deep or fast breathing with dizziness
- itching skin
- mental confusion
- numbness of feet, hands and around mouth
- trembling or shaking of hands or feet shakiness in legs, arms, hands, or feet
- unusually large pupils of eyes
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.
More about Antiflex (orphenadrine)
- Side effects
- Drug interactions
- Dosage information
- During pregnancy
- Reviews (1)
- Drug class: skeletal muscle relaxants
- Latest FDA Alerts (1)
Related treatment guides
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.