Sounds like 'or-FEN-uh-dreen'

Orphenadrine is used treat muscle spasms and pain such as back pain and tension headaches. Find out how to take it safely and possible side effects. Orphenadrine is also called Norflex.

Type of medicine Also called
  • Muscle relaxant
  • Norflex®

What is orphenadrine?

Orphenadrine is used to treat muscle spasms and pain such as back pain and tension headaches. It may be helpful for short-term relief and is usually used together with other therapies such as physiotherapy and exercise. Orphenadrine acts in your central nervous system to produce its muscle relaxant effects. Read more about back painwhat to do if you have back pain and tension headaches. In New Zealand orphenadrine is available as tablets and is only available on prescription from your doctor.


  • Orphenadrine is available as tablets (100 mg).
  • The usual dose of orphenadrine is 1 tablet two times a day. 
  • It is recommended for short-term use.
  • Always take your orphenadrine exactly as your doctor has told you.
  • The pharmacy label on your medicine will tell you how much to take, how often to take it and any special instructions.

How to take orphenadrine

  • Timing: Take your orphenadrine doses at the same times each day, in the morning and the evening. Swallow your tablets with a glass of water. You can take orphenadrine with or without food.
  • Missed dose: If you miss a dose and remember within an hour or so of the missed dose, take it right away. But, if you do not remember until later, just take the next dose at the right time. Do not take double the dose.

Precautions before starting orphenadrine

  • Do you have glaucoma (raised pressure in your eyes)?
  • Do you have stomach problems such as reflux or stomach ulcers?
  • Do you have a condition called myasthenia gravis?
  • Do you have problems passing urine or an enlarged prostate?
  • Do you have problems with your heart?
  • Do you have problems with your liver or kidneys?
  • Are you pregnant or planning a pregnancy?
  • Do you have constipation?
  • Are you elderly?

If so, it’s important that you tell your doctor or pharmacist before you start taking orphenadrine. Sometimes a medicine isn’t suitable for a person with certain conditions or it can only be used with extra care.

What are the side effects of orphenadrine?

Like all medicines, orphenadrine can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine.

Side effects What should I do?
  • Constipation
  • This is quite common when you start taking orphenadrine.
  • Ask your doctor to prescribe a laxative, which you need to take on a regular basis.
  • You also need to eat more fruit, vegetables, brown bread and bran-based breakfast cereals and drink plenty of water.
  • Tell your doctor if troublesome.
  • Dry mouth
  • This is quite common when you start taking orphenadrine.
  • Try using sugarless gum or lollies, melt some ice in your mouth or use a saliva substitute.
  • Tell your doctor if troublesome and continues for longer than 2 weeks.
  • Feeling sleepy, dizzy or tired
  • This is common when starting orphenadrine or after increasing the dose.
  • Be careful when driving or using tools until you know how this medicine affects you.
  • Do not drink alcohol.
  • Nausea (feeling sick) or vomiting (being sick) 
  • Tell your doctor if troublesome.
  • Fast heart rate, palpitations
  • Tell your doctor.
  • Problems with your eyesight 
  • Tell your doctor.
  • Signs of an allergic reaction such as shortness of breath, trouble breathing, tightness in your chest
    and wheezing and skin rash
  • Tell your doctor immediately or ring HealthLine 0800 611 116.
Did you know that you can report a side effect to a medicine to CARM (Centre for Adverse Reactions Monitoring)? Report a side effect to a product


Orphenadrine interacts with some other medications and herbal supplements, so check with your doctor or pharmacist before starting orphenadrine or before starting any new medicines. 

Learn more

The following link has more information on orphenadrine.

Norflex Medsafe Consumer Information Sheets


  1. Orphenadrine citrate New Zealand Formulary
  2. Low back pain: a pathway to prioritisation National Health Committee, 2015
Credits: Sandra Ponen, Pharmacist. Reviewed By: Angela Lambie, Pharmacist, Auckland Last reviewed: 27 Aug 2018