What is norpiflex used for?

October 7, 2025 •

3 min read

The brand name Norpiflex is discontinued in the U.S., but its active ingredient, orphenadrine, is still available and is most commonly used as a muscle relaxant to treat painful musculoskeletal conditions. This medication is prescribed as part of a treatment plan that typically includes rest and physical therapy.

Quick Summary

Norpiflex, orphenadrine, is a muscle relaxant used to alleviate pain and discomfort from acute musculoskeletal conditions like strains and sprains. It works by affecting the central nervous system and is available as a generic prescription medication.

Key Points

Discontinued Brand Name: Norpiflex is a discontinued brand name for the generic muscle relaxant, orphenadrine.
Primary Use: The medication is used to relieve discomfort and pain associated with acute musculoskeletal conditions, such as strains and sprains.
Acts on the CNS: Orphenadrine works in the central nervous system, rather than directly on the muscles, to block nerve impulses and relieve muscle spasms.
Common Side Effects: Users frequently experience dry mouth, drowsiness, and dizziness due to the medication's anticholinergic effects.
Important Warnings: It should be used with caution, especially in older adults and those with heart problems, and should not be combined with alcohol or other CNS depressants.
Contraindications: Individuals with glaucoma, myasthenia gravis, or certain gastrointestinal or urinary issues should not take this medication.

Understanding Norpiflex and Its Active Ingredient

Norpiflex is a discontinued brand name for the generic drug orphenadrine citrate. Despite the brand name no longer being available in the U.S., the active ingredient, orphenadrine, is still used and prescribed today. It belongs to a class of medications called skeletal muscle relaxants and is used as an adjunct to rest, physical therapy, and other measures for the relief of discomfort associated with acute painful musculoskeletal conditions. Its precise mechanism of action is not fully understood but is believed to involve central nervous system (CNS) depression and anticholinergic effects, which interfere with nerve impulses.

Primary Uses for Orphenadrine

The primary therapeutic application of orphenadrine is to relieve the stiffness, pain, and discomfort caused by muscle-related injuries. This includes issues like:

Muscle strains
Sprains
Other musculoskeletal injuries

By calming overactive nerves, the medication helps to relax the affected muscles, which can provide significant pain relief. It is important to note that orphenadrine does not directly relax tense muscles but rather acts on the nervous system to produce its effect. This medication is typically prescribed for short-term use in managing these conditions.

Mechanism of Action

The way orphenadrine works is not entirely clear, but research suggests it operates on several levels:

CNS Depression: The medication is thought to depress the central nervous system, which helps to inhibit nerve impulses sent from the brain and spinal cord to the muscles. This central action contributes to involuntary muscle relaxation and the reduction of spasms and pain.
Anticholinergic Properties: Orphenadrine possesses anticholinergic actions, which means it blocks the effects of acetylcholine, a neurotransmitter. This action also plays a role in inhibiting nerve impulses and promoting muscle relaxation. These properties also cause many of the medication's common side effects, such as dry mouth and blurred vision.

Side Effects, Warnings, and Precautions

Like all medications, orphenadrine can cause side effects. Due to its anticholinergic properties, many common side effects are related to blocking acetylcholine.

Common Side Effects

Dry mouth
Dizziness and drowsiness
Constipation
Blurred vision
Nausea and vomiting
Headache

Less Common but Serious Side Effects

Fast or irregular heartbeat
Confusion, agitation, or hallucinations
Increased eye pressure (can worsen glaucoma)
Difficulty urinating
Fainting or lightheadedness
Signs of a serious allergic reaction, such as hives or breathing problems

Warnings and Precautions

Driving and Operating Machinery: Due to the risk of dizziness and drowsiness, patients should not drive or operate heavy machinery until they understand how the medication affects them.
Older Adults: Caution is advised when prescribing orphenadrine to patients over 65, as they may be more susceptible to side effects like confusion and mental status changes.
Contraindications: Orphenadrine should not be used in individuals with conditions such as glaucoma, myasthenia gravis, certain intestinal obstructions, an enlarged prostate, or heart problems.
Drug Interactions: Combining orphenadrine with other CNS depressants, including alcohol, opioids, and benzodiazepines, can increase the risk of dangerous side effects like excessive sedation and respiratory depression.

Norpiflex (Orphenadrine) vs. Cyclobenzaprine (Flexeril)


Feature	Orphenadrine (Norpiflex)	Cyclobenzaprine (Flexeril)
Mechanism of Action	Thought to act on the central nervous system to block nerve signals; has anticholinergic properties.	Works in the brainstem to relieve muscle spasms; mechanism also involves CNS action.
Common Use	Prescribed for acute musculoskeletal pain.	Prescribed for muscle spasm associated with acute painful musculoskeletal conditions.
Drug Class	Skeletal muscle relaxant.	Skeletal muscle relaxant.
Availability	Available as a generic (brand Norflex discontinued).	Available as both brand name (Flexeril) and generic.
Common Side Effects	Dry mouth, dizziness, drowsiness, blurred vision.	Dry mouth, dizziness, drowsiness.
Special Considerations	Potential for increased heart rate; not recommended for those with certain heart problems.	Not recommended for those with severe liver problems; has higher risk of interactions with serotonergic drugs.

Conclusion

Norpiflex is the discontinued brand name for orphenadrine, a prescription muscle relaxant used to treat pain and discomfort from acute musculoskeletal conditions. It works by affecting the central nervous system rather than acting directly on the muscles. Treatment with orphenadrine is typically short-term and is used in conjunction with rest and physical therapy. Patients should be aware of its potential side effects, especially dizziness and drowsiness, which can impact daily activities. It is contraindicated in people with certain pre-existing health conditions, and caution is necessary when taking it with other CNS depressants or alcohol. As with any prescription medication, it is crucial to follow a healthcare provider's instructions carefully and discuss any concerns, medical history, or other medications with them before use.

For more detailed information, consult the MedlinePlus drug information page for orphenadrine.

Frequently Asked Questions

Orphenadrine is a skeletal muscle relaxant used to relieve pain, stiffness, and discomfort from acute musculoskeletal conditions like strains and sprains.

The brand name Norpiflex is discontinued in the U.S., but its active ingredient, orphenadrine, is still widely available as a generic prescription medication.

Its exact mechanism is not fully understood, but it is believed to act on the central nervous system to inhibit nerve impulses and block certain nerve cell communications through its anticholinergic properties.

Common side effects include dry mouth, drowsiness, dizziness, constipation, and blurred vision.

No, you should avoid alcohol. Orphenadrine can increase drowsiness and impair judgment, and combining it with alcohol can dangerously amplify these effects.

Individuals with certain medical conditions, such as glaucoma, myasthenia gravis, enlarged prostate, intestinal blockage, or heart problems, should not take orphenadrine.

Oral tablets should be taken as directed by your doctor. Extended-release tablets must be swallowed whole and not crushed or chewed.

Orphenadrine is typically intended for short-term use. The safety of continuous long-term therapy has not been established.