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Orphenadrine (anticholinergic, muscle relaxant)

Know the basics|Know the precautions & warnings|Know the side effects|Know the interactions|Understand the dosage

Orphenadrine is an anticholinergic drug that relaxes the muscles. It treats muscle spasms, which are involuntary muscle contractions caused by inappropriate firing of nerve impulses. Such spasms can cause severe pain or disability in some cases.

Know the basics

What is orphenadrine used for?

Orphenadrine, together with rest and physical therapy, relaxes muscles and prevents spasms and pain. Another use for orphenadrine is to treat parkinsonism.

How should I take orphenadrine?

Read the directions on the packaging for complete information. Check the label and expiration date.

For oral dosage forms, swallow it whole without chewing, crushing, or dissolving it in liquid.

For parenteral dosage forms, only a licensed healthcare professional should administer it.

How do I store orphenadrine?

Store this product at room temperature away from direct light and moisture. To prevent drug damage, you should not store it in the bathroom or the freezer.

There may be different brands of this drug that may have different storage needs. So, it is important to always check the product package for instructions on storage, or ask your pharmacist. For safety, you should keep all medicines away from children and pets.

You should not flush this product down the toilet or pour them into a drain unless instructed to do so. Additionally, it is important to properly discard this product when it is expired or no longer needed. Consult your pharmacist for more details about how to safely discard your product.

Know the precautions & warnings

What should I know before using orphenadrine?

Before using this drug, tell your doctor if you are/have:

  • Pregnant or breastfeeding.
  • Taking any other medicines. This includes any prescription, OTC, and herbal remedies.
  • An allergy to any of the ingredients of this product.
  • Any other illnesses, disorders, or medical conditions.

Is it safe during pregnancy or breastfeeding?

Unfortunately, there isn’t enough information about the safety of using this drug during pregnancy and breastfeeding. Please always consult with your doctor to weigh the potential benefits and risks before taking any medication.

This medication is pregnancy risk category C according to the US Food and Drug Administration (FDA).

FDA pregnancy risk category reference below:

  • A= No risk
  • B= No risk in some studies
  • C= There may be some risk
  • D= Positive evidence of risk
  • X= Contraindicated
  • N= Unknown

Know the side effects

What are the side effects of orphenadrine?

Like all drugs, this product may have side effects. If they occur, side effects are generally mild and resolve once treatment is finished or the dose is lowered. Some reported side effects include:

  • Tachycardia
  • Confusion
  • Anxiety
  • Agitation
  • Tremors
  • Hallucinations
  • Convulsions
  • Decrease in urination
  • Dry mouth or throat
  • Blurred vision
  • Dilated pupils
  • Headache
  • Drowsiness
  • Dizziness
  • Nausea
  • Vomiting
  • Constipation
  • Weakness
  • Dependency

However, not everyone experiences these side effects. In addition, some people may experience other side effects. So, if you have any concerns about a side effect, please consult your doctor or pharmacist.

Know the interactions

What drugs may interact with orphenadrine?

This medication may interact with other drugs that you are currently taking, which can change how your drug works or increase your risk for serious side effects.

To avoid any potential drug interactions, you should keep a list of all the drugs you are using (including prescription drugs, nonprescription drugs, and herbal products) and share it with your doctor and pharmacist.

Drugs with known interactions:

  • Alfentanil
  • Anileridine
  • Buprenorphine
  • Codeine
  • Fentanyl
  • Hydrocodone
  • Hydromorphone
  • Levorphanol
  • Meperidine
  • Methadone
  • Morphine
  • Oxycodone
  • Oxymorphone
  • Propoxyphene
  • Remifentanil
  • Sodium Oxybate
  • Sufentanil
  • Suvorexant
  • Tapentadol
  • Umeclidinium

If you experience an adverse drug interaction, inform your doctor immediately to reevaluate your treatment plan. Approaches include dose adjustment, drug substitution, or ending therapy.

Does food or alcohol interact with orphenadrine?

This drug may interact with food or alcohol by altering the way the drug works or increase the risk for serious side effects. Do not consume alcohol while taking this drug. Please discuss with your doctor or pharmacist any potential food or alcohol interactions before using this drug.

What health conditions may interact with orphenadrine?

This drug may interact with underlying conditions. This interaction may worsen your health condition or alter the way the drug works. Therefore, it is important to always let your doctor and pharmacist know all the health conditions you currently have, especially:

  • Enlarged prostate
  • Tardive dyskinesia
  • Porphyria
  • Urinary retention
  • Paralytic ileus
  • Pyloric stenosis
  • Glaucoma
  • Hyperpyrexia
  • Cardiospasm
  • Myasthenia gravis

Understand the dosage

The information provided is not a substitute for any medical advice. Therefore, you should always consult with your doctor or pharmacist before using any medication.

What is the dose for an adult?


Initially, take 150 mg 0f per day (in divided doses). The dose may be increased by 50 mg every 2 to 3 days. The maintenance dose is 150 to 300 mg per day, up to 400 mg in a single day.

Muscle spasms

Take 100 mg twice a day, as an oral tablet or solution. For intramuscular or intravenous route, administer 60 mg every 12 hours.

What is the dose for a child?

The dosage has not been established in pediatric patients. It may be unsafe for your child. It is always important to fully understand the safety of the drug before using. Please consult with your doctor or pharmacist for more information.

How is orphenadrine available?

Orphenadrine is available in the following dosage forms and strengths:

  • Oral tablet: 50 mg
  • Extended-release tablet: 100 mg
  • Oral solution: 50 mg/5 mL
  • Solution for injection: 30 mg/mL

What should I do in case of an emergency or overdose?

In case of an emergency or an overdose, call your local emergency services or go to the nearest emergency room.

What should I do if I miss a dose?

If you miss a dose, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose.

Hello Health Group does not provide medical advice, diagnosis or treatment.


Orphenadrine https://www.mims.com/philippines/drug/info/orphenadrine?mtype=generic Accessed July 21, 2021

Orphenadrine (Oral Route) https://www.mayoclinic.org/drugs-supplements/orphenadrine-oral-route/description/drg-20065214 Accessed July 21, 2021

Orphenadrine tablets https://my.clevelandclinic.org/health/drugs/20288-orphenadrine-tablets Accessed July 21, 2021

Orphenadrine citrate – Drug Summary https://www.pdr.net/drug-summary/Orphenadrine-Citrate-Extended-Release-Tablets-orphenadrine-citrate-1580 Accessed July 21, 2021

Orphenadrine. Lexi-Drugs. Lexicomp. Wolters Kluwer Health, Inc. Riverwoods, IL. Accessed July 21, 2021. http://online.lexi.com

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Written by Stephanie Nicole Nera, RPh, PharmD Updated Jul 23, 2021