How does this medication work? What will it do for me?

This combination product contains three medications: acetylsalicylic acid (ASA), methocarbamol, and codeine.

ASA belongs to the group of medications called analgesics (pain relievers), anti-inflammatories, and antipyretics (fever reducers).

Methocarbamol belongs to the group of medications called muscle relaxants.

Codeine belongs to the group of medications called narcotic analgesics.

ASA - methocarbamol - codeine phosphate is used for the relief of pain associated with muscle spasm, strains and sprains, low back pain, tendon pain, and muscle pain resulting from injury.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. As well, some forms of this medication may not be used for all of the conditions discussed here. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

What form(s) does this medication come in?

C ½
Each coral and white tablet, white layer monogrammed "RO", contains methocarbamol 400 mg, ASA 325 mg, and codeine phosphate 32.4 mg. Nonmedicinal ingredients: cellulose, cornstarch, FD&C Blue No. 1, FD&C Red No. 40, FD&C Yellow No. 6, magnesium stearate, polyethylene glycol, povidone, sodium starch glycolate, and stearic acid.

C ¼
Each orange and white tablet, orange layer monogrammed "RO", contains ASA 325 mg, methocarbamol 400 mg, and codeine phosphate 16.2 mg. Nonmedicinal ingredients: cornstarch, FD&C Yellow No. 6, magnesium stearate, povidone, sodium starch glycolate, and stearic acid.

How should I use this medication?

The usual adult dose is 1 or 2 tablets 3 or 4 times daily.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to take this medication exactly as prescribed by your doctor. If your doctor has told you to take this medication on a regular basis and you miss a dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature, protect it from light and moisture, and keep it out of the reach of children.

This medication is available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms listed here. The forms available for the specific brand you have searched are listed under "What form(s) does this medication come in?"

Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.

Who should NOT take this medication?

Do not use this medication if you:

  • are allergic to methocarbamol, ASA, codeine, or any of the ingredients of the medication
  • are 12 years of age or younger
  • have an active stomach ulcer
  • have had a bronchospastic reaction (severe asthma-type reaction), generalized hives, severe running and itching nose, or shock brought on by ASA or nonsteroidal anti-inflammatory drugs

What side effects are possible with this medication?

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

  • diarrhea
  • dizziness
  • drowsiness
  • dry mouth
  • headache
  • heartburn
  • lightheadedness
  • nausea
  • stomach upset
  • vomiting

Although most of these side effects listed below don't happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

  • abdominal pain
  • constipation
  • hearing loss
  • ringing in the ears
  • signs of an allergic reaction (e.g., rash, hives or itching)
  • signs of decreased kidney function (e.g., difficulty or pain urinating, frequent urge to urinate, decrease in amount of urine)
  • signs of unusual bleeding (e.g., bloody or black, tarry stools, vomiting of blood or material that looks like coffee grounds, unusual bruising or bleeding, nosebleeds)

Stop taking the medication and seek immediate medical attention if any of the following occur:

  • signs of a serious allergic reaction (e.g., abdominal cramps, difficulty breathing, nausea and vomiting, or swelling of the face and throat)
  • signs of a severe skin reaction such as blistering, peeling, a rash covering a large area of the body, a rash that spreads quickly, or a rash combined with fever or discomfort
  • signs of breathing problems such as shallow, irregular breathing, or slow or troubled breathing
  • symptoms of overdose of codeine, such as:
    • abnormally slow, weak breathing
    • cold, clammy skin
    • confusion
    • extreme drowsiness
    • severe dizziness
    • slow heartbeat

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Are there any other precautions or warnings for this medication?

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

HEALTH CANADA ADVISORY

July 28, 2016

Health Canada has issued new information concerning the use of Methoxisal-C, Robaxisal-C, and Spasmhalt -ASA-8 (ASA - methocarbamol - codeine). To read the full report, visit Health Canada's website at www.hc-sc.gc.ca.

Previous advisories on ASA - methocarbamol - codeine were issued on June 6, 2013 and October 17, 2013.

Abdominal conditions: Codeine may make the diagnosis of abdominal conditions more difficult or it may worsen these conditions. If you have an abdominal condition such as inflammatory or obstructive bowel disease, acute cholecystitis, or pancreatitis, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Breathing: Codeine can suppress breathing. If you are at risk for breathing difficulties, such as asthma, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Constipation: Codeine can be very constipating. Eating a high-fibre diet and following good bowel habits will help to minimize this effect. If you develop constipation easily, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Dependence and withdrawal: This medication contains codeine. Physical dependence, psychological dependence, and abuse have occurred with the use of codeine. People with a history of past or current substance use problems may be at greater risk of developing abuse or addiction while taking this medication. Abuse is not a problem with people who require this medication for pain relief.

If you suddenly stop taking this medication, you may experience withdrawal symptoms such as anxiety, sweating, trouble sleeping, shaking, pain, nausea, tremors, diarrhea, and hallucinations. If you have been taking this medication for a while, it should be stopped gradually as directed by your doctor.

Drowsiness/reduced alertness: This medication may cause drowsiness. Do not drive, operate machinery, or perform other potentially hazardous tasks until you have determined how this medication affects you.

Head injury: If you have a head injury or increased pressure in the head, you may have a higher risk of experiencing side effects (breathing problems) or worsening of their condition while taking this medication. Discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Kidney function: Taking ASA - methocarbamol - codeine over a long period of time may increase the risk of developing kidney disease. If you have kidney disease or reduced kidney function, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Liver function: If you have liver disease or reduced liver function, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Other medical conditions: If you are about to undergo surgery of the biliary tract, approach taking codeine with caution, as it may worsen your condition. Codeine will worsen the effects of acute alcohol intoxication and delirium tremens.

As well, if you have low thyroid (hypothyroidism), Addison's disease, benign prostatic hypertrophy (enlarged prostate), gallbladder disease, urethral stricture, decreased function of the adrenal glands, or porphyria, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Surgery: Do not take ASA - methocarbamol - codeine for 5 to 7 days before any surgery, including dental surgery, unless otherwise directed by your doctor or dentist. If you are scheduled for surgery, let your doctor know that you are taking this medication.

Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast feeding: Codeine passes into breast milk. Some of the codeine dose is converted into morphine by the body, once it has been taken. For some people, this change happens much faster than for others. If this happens to a nursing mother, the baby is a risk of receiving a morphine overdose through the breast milk.

If you are a breast-feeding mother and are taking ASA - methocarbamol - codeine, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using this medication have not been established for children.

The use of ASA may be associated with the development of Reye's syndrome in children and teenagers who have illnesses accompanied by fever, especially influenza and chickenpox. ASA should not be given to, or used by, children or teenagers who have chickenpox or flu symptoms unless a doctor is consulted.

Seniors: Seniors may be more susceptible to the harmful effects of ASA.

What other drugs could interact with this medication?

There may be an interaction between ASA - methocarbamol - codeine and any of the following:

  • acetazolamide
  • alcohol
  • alendronate
  • alteplase
  • anaesthetics
  • angiotensin converting enzyme inhibitors (ACEIs; e.g., captopril, ramipril)
  • antihistamines (e.g., cetirizine, dimenhydrinate, diphenhydramine, hydroxyzine)
  • antipsychotics (e.g., haloperidol, quetiapine, olanzapine, risperidone)
  • baclofen
  • barbiturates (e.g., butalbital, phenobarbital, secobarbital)
  • benzodiazepines (e.g., alprazolam, diazepam, lorazepam)
  • bupropion
  • buspirone
  • butorphanol
  • calcium channel blockers (e.g., diltiazem, nifedipine, verapamil)
  • chloral hydrate
  • corticosteroids (e.g., dexamethasone, prednisone, methylprednisolone)
  • cyclobenzaprine
  • dasatanib
  • desvenlafaxine
  • divalproex sodium
  • fluoroquinolone antibiotics (e.g., ciprofloxacin, norfloxacin, moxifloxacin)
  • furosemide
  • ginkgo biloba
  • glucosamine
  • ketorolac
  • live influenza virus vaccine
  • methotrexate
  • monoamine oxidase inhibitors (e.g., tranylcypromine, phenelzine, moclobemide)
  • non-steroidal anti-inflammaotry medications (NSAIDs; e.g., diclofenac, ibuprofen, naproxen)
  • other narcotic analgesics (e.g., fentanyl, morphine, oxycodone)
  • pentazocine
  • pentoxiphylline
  • phenothiazines (e.g., perphenazine, thioridazine)
  • phenylbutazone
  • probenecid
  • pyridostigmine
  • selective serotonin reuptake inhibitors (e.g., citalopram, fluoxetine, sertraline)
  • sulfinpyrazone
  • tetracycline antibiotics (e.g., doxycycline, minocycline, tetracycline)
  • thiazide diuretics (e.g., hydrochlorothiazide, indapamide)
  • tricyclic antidepressants (e.g., amitriptyline, desipramine, imipramine)
  • valproic acid
  • varicella virus vaccine (chickenpox vaccine)
  • warfarin

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

  • stop taking one of the medications,
  • change one of the medications to another,
  • change how you are taking one or both of the medications, or
  • leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.