The lay of the land
Cyclobenzaprine, the active ingredient.
Therapeutic use: a centrally acting muscle relaxant prescribed for short term relief of acute musculoskeletal spasm accompanied by pain.
Common dosage forms internationally include immediate release 5 mg and per tablet 10 mg and extended release 15 mg and 30 mg formulations. This page refers to 15 mg where noted.
Cyclobenzaprine is normally combined with rest and physical therapy to help reduce painful muscle tightness after sprain, strain or other injury. For cautionary safety notes, see the sections on precautions and clear contraclues that suggest to therapy.
The Core Idea of How It Works
Cyclobenzaprine alters activity in the central nervous system to reduce tonic somatic motor activity and decrease muscle hyperactivity. It does not act directly on skeletal muscle fibers but influences the neural signals that cause involuntary muscle tightness.
Dose Information and Directions
Observe the prescriber's instructions exactly as directed. Cyclobenzaprine is generally intended for brief courses, commonly two to three weeks, and only while other measures are being used.
- Take doses at consistent times each day for best effect.
- Do not exceed the prescribed frequency or duration of therapy.
- Extended release 15 mg tablets are usually taken once daily; immediate release tablets are often split across the day.
If symptoms have not improved after a short treatment period, arrange a review with the prescribing clinician to reassess need for continued therapy.
Risk mitigation steps
- Inform your clinician if you have liver disease, glaucoma, an enlarged prostate, urinary retention, or thyroid problems.
- Older adults can be more prone to drowsiness, dizziness and confusion; dose reduction or a further option therapy may be appropriate.
- Prenatal to lactation care data are limited; seek medical advice if you are pregnant, planning a pregnancy, or breastfeeding.
- Cyclobenzaprine can produce sedation. Avoid driving, using tools or machinery until you know how the medicine affects you.
- Be aware of signs of serotonin syndrome; see the probable adverse reactions details segment.
Not recommended in these scenarios
- Recent myocardial infarction, severe heart failure, clinically significant arrhythmias or conduction problems.
- Uncontrolled hyperthyroidism or other serious thyroid dysfunction.
- Concurrent or recent use of monoamine oxidase inhibitors (MAOIs) within 14 days; examples include isocarboxazid, phenelzine, rasagiline, selegiline and tranylcypromine. Combining these medicines can cause severe reactions.
Possible adverse impact on health
Seek emergency care for signs of an allergic reaction such as hives, swelling of the face, lips, tongue or throat, or difficulty breathing.
Stop treatment and obtain urgent medical assessment if you experience chest pain, fast or irregular heartbeat, sudden weakness or numbness, trouble speaking, or loss of coordination.
Serotonin syndrome is a serious risk when cyclobenzaprine is combined with serotonergic agents. Symptoms include agitation, hallucinations, high temperature, sweating, tremor, muscle rigidity, fast pulse, and nausea or vomiting. If these occur, get urgent medical help.
More common, less severe reactions include drowsiness, fatigue, disabling headache, dizziness, dry mouth, nausea and constipation.
Potential Interpersonal engagements Between Drugs
Cyclobenzaprine may increase sedation from other central nervous system depressants. Discuss all current medicines with your prescriber before starting this drug.
- Opioids, benzodiazepines, hypnotics and other muscle relaxants can intensify drowsiness and respiratory depression.
- Serotonergic medicines such as SSRIs, SNRIs, tramadol, certain antiemetics and some Parkinson medicines raise the risk of serotonin syndrome when combined with cyclobenzaprine.
- Anticholinergic drugs including some antihistamines, medications for overactive bladder or motion sickness may accentuate dry mouth, constipation and confusion.
- Medicines specifically reported to interact include bupropion, meperidine, tramadol and certain calcium channel blockers like verapamil.
- Avoid alcohol while taking cyclobenzaprine as it increases sedation and impairs coordination.
Untaken dose
If you forget to take one dose, take it immediately after you remember, unless the next dose is imminent. In that case skip the the medication dose was missed and continue with the regular schedule. Do not replace a the medication dose was missed by doubling it.
Overdose tragedy
Excessive drug intake related signs can include extreme drowsiness, vomiting, rapid or irregular heartbeat, tremor, agitation or hallucinations. An overdose event poses a life threatening risk. Contact emergency services or your local poison information line immediately.
Storage facility
- Keep all drugs out of the reach and sight of children.
- Store in a tightly closed container at room temperature, ideally between 15 and 30 degrees C (59 to 86 degrees F).
- Dispose of expired or unwanted tablets safely; do not use after the expiry date.
Alternate options and Related Pharmaceuticals
Depending on the clinical situation and availability in Australia, prescribers may consider:
- Baclofen (oral) - often used for spasticity and sometimes for acute spasm; commonly PBS-listed within the land of Australia.
- The drug Tizanidine - an alpha-2 agonist muscle relaxant; expect sedation and possible to achieve low blood pressure.
- Diazepam - a benzodiazepine with muscle relaxant effects; use is usually short term because of dependence and sedation risks.
- Orphenadrine - anticholinergic antispasmodic; can reduce spasm but has anticholinergic lingering reactions.
- Methocarbamol and metaxalone - centrally acting relaxants; availability and use vary by country.
Non-drug approaches such as rest, heat or cold, graded exercise and physiotherapy are important first-line options and often reduce the need for medicines.
Scan the rates and prices section for a rough cost comparison along with the legal entitlement to access section for availability pathways throughout Australia.
Australian prices expressed in AUD
Costs depend on supplier, pack size and whether the medicine is subsidised under the Pharmaceutical Benefits Scheme (PBS). The figures below are indicative and for guidance only.
- Cyclobenzaprine (Flexeril): Not commonly marketed australia-based. Private purchase via import or overseas prescriptions can cost about AUD 0.80 to AUD 2.50 per 10-15 mg tablet before shipping and handling. Shipping or pharmacy dispensing fees may add about AUD 10 to AUD 25.
- Baclofen (generic): Widely available and often PBS-subsidised. Private price for 100 x 10 mg dose tablets may be around AUD 10 to AUD 25; PBS co-payment for general patients is typically about AUD 30 to AUD 32, and around AUD 7 to AUD 8 for concession card holders.
- Diazepam (generic): Low cost when available; private packs may be AUD 5 to AUD 15. PBS co-payment rates similar to those listed above where applicable.
- Tizanidine capsule: Private prices vary, roughly AUD 15 to AUD 40 per pack where sold; PBS coverage may not apply to all strengths or indicators.
Your actual out of pocket cost will vary by pharmacy, location, insurance and PBS eligibility. Always request a current price from your pharmacist or supplier before purchase.
The status of legality by jurisdiction in Australia
Summary: Cyclobenzaprine is not routinely marketed across Australia. When supplied it is treated as a prescription-only medicine and access is controlled by the Therapeutic Goods Administration (TGA) regulations.
- Prescription only (Schedule 4): If supplied, cyclobenzaprine requires a prescription and medical supervision.
- Special Access Scheme (SAS): Prescribers can apply for patient-specific access to unapproved medicines under SAS Category B where clinically justified.
- Authorised Prescriber route: A clinician may obtain approval to prescribe certain unapproved medicines to specified patient groups.
- Personal importation: Individuals may import a limited supply (commonly up to three months) of prescription medicines for personal use when they hold a valid prescription and meet Customs and TGA requirements. Documentation and correct packaging are important; some products may be prohibited.
Driving and workplace safety: Australian road rules and workplace regulations prohibit performing safety-sensitive tasks while impaired. Sedating medicines like cyclobenzaprine can affect driving or operating machinery.
PBS and insurance: Because cyclobenzaprine is generally not PBS-listed, government subsidy is unlikely. Patients should expect to pay private or import costs unless a specific subsidy or an alternate solution is available.
This information is a general summary and not legal advice. For current regulatory requirements consult the TGA, your prescriber or pharmacist.
Quick Facts
- Indication: short term relief of acute skeletal muscle spasm with associated pain.
- Typical treatment length: usually limited to two to three weeks.
- Main cautions: sedation, anticholinergic effects such as dry mouth and constipation, and high priority communication in actions in the user journey shape satisfaction. with MAOIs and serotonergic medicines.
- Cast your gaze on the clinically relevant drug interacting with others possibilities and unintended consequences sections for more safety detail.
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