Muscular spasms can be painful. A spasm is experienced when a muscle twitches on its own, in an involuntary manner. Some of these episodes can be painful, showing up as discomforts in your lower back or neck. It is in such instances your doctor may prescribe a muscle relaxer. Most muscle relaxers are used only for a shorter span of time. As these drugs are often habit forming, the dosages and duration of medication plan are under close clinical supervision. These drugs are also likely to trigger a few side effects. It is wise to know the likely discomforts, side effects or allergies before taking muscle relaxing drugs.

Muscle relaxers are treatment options for acute muscular pains as well as spasms. In case of chronic pains, these drugs are not prescribed. You need to know there are two broad categories of muscle relaxing meds namely, anti-spastics and antispasmodics. Of these two types, anti-spastics are mainly used for treating muscular spasms and tightness of muscles. This class of drugs mainly work on your spine as well as on your musculoskeletal system. On the other hand, antispasmodics also aim to bring needful relief from discomforts and pains associated with spasms. But, instead of working on your spinal cord, this family of muscle relaxants work its way through your nerves or the central nervous system (CNS).

Foremost of all, you must remember the aforesaid two categories are distinct and different; though they work to bring about similar outcomes. For this reason, an anti-spastic drug is never used as a replacement for an antispasmodic drug. Also, the side effects each of these meds may trigger are also different.

Side effects of anti-spastic muscle relaxers

As mentioned, these drugs work on your spinal-cord to reduce spasms and pains. Since the mechanism of these drugs involves your spinal system, they are also used for treating palsies, injuries in the spine, etc. Drugs such as dantrolene, baclofen, etc. are categorised as anti-spastic muscle relaxers. Common side effects of such drugs include dizziness, being in a confused state of mind, dryness of mouth, blurring of eyesight, hypotension or drop in blood pressure level, itchiness, etc.

Dantrolene – This drug is used for the treatment of spasms and pains in your muscles. It is usually prescribed in dosage forms of less than 20 to 25 milligrams per day. It needs to be taken only for a very short term. The medication plan involving dantrolene is usually less than 6 to 7 days. You need to remember that an intravenous form of this drug is also available; this form is administered in some rare cases of acute pains and muscular-spasticity.

Side effects of dantrolene – Your doctor may not prescribe oral-intake of dantrolene as it can damage your liver. So, if you are already having medical conditions such as hepatitis (i.e., inflammation of liver) or cirrhosis, you need to stay away from oral administration of dantrolene. In case of intravenous delivery of this drug, some people have witnessed tiredness, excessive levels of weariness, breathing problems, etc. Among all these side effects, respiratory conditions are known to develop due to weakness experienced in the muscles of your air pathways as well as lungs.

Baclofen – This is another widely used anti-spastic medicine. You need to know, this has the approval of the food and drug administration (FDA) in the US, to treat spasms and associated muscular discomforts. It can be an effective muscle relaxant for those living with spinal cord problems or injuries, multiple sclerosis as well as conditions like clonus.

Clonus is a nerve condition wherein the cells controlling your muscular tissues are impaired. The commonly prescribed dosage is never than 70 milligrams (mg) each day. For the treatment of normal episodes of spasms, a much lower dosage – of say, less than 15 mg is prescribed. Each dose is in the range of 5 mg and you may be advised to take it twice or thrice daily. This drug is also not prescribed for a long term use. The timeline of a typical medication plan is in the range of 5 to 7 days.

Side effects of baclofenBaclofen is known to trigger a few discomforts and adverse side effects. Such effects include dizziness, feeling drowsy, experiencing frequent spells of confusion, tiredness, abdominal problems like indigestion, nausea, etc., weariness and weakness. These effects may however disappear soon after starting the medication plan. But, if one or more of these discomforts are known to persist, you need to consult your treating physician as soon as possible.

People who have allergies to baclofen are likely to develop swelling or breathing problems. Upon noticing any of these serious symptoms, you are advised to call 911 immediately. It is also a good practice to call the hotline numbers of the food and drug administration (as this agency keeps a close watch over the drugs it has approved) or contact a poison control center nearby.

Side effects of antispasmodic muscle relaxing drugs

Unlike anti-spastic muscle relaxing meds, the mechanism of action of these drugs focuses on your nerves. This family of drugs are further classified into non-benzodiazepines and benzodiazepines. The key difference is non-benzodiazepines work on your spinal cord as well as brain; while, benzodiazepines are found to concentrate only on brain for needful relief from pains and muscular spasms. The most common side effects of non-benzodiazepines are headache, feeling dizzy, spells of drowsiness, dryness of mouth due to dehydration, being in an irritated frame of mind, abdominal problems such as nausea or vomiting. A few examples of antispasmodic muscle relaxers are cyclobenzaprine (comes under the non-benzodiazepine sub-category), diazepam (belonging to the benzodiazepine sub-segment), etc.

Cyclobenzaprine – This muscle relaxing drug comes under the non-benzodiazepine class of meds. It is often administered as part of a comprehensive treatment plan involving therapy and plenty of rest. Your doctor may choose an apt form of this muscle relaxing drug among its dual versions – namely, extended release version and an immediate release version. If you are consuming the extended release version, it is highly recommended to take it at the same time every day.

Commonly administered dosage is about 5 milligrams each day for a shorter time span. Your doctor will ensure that the daily dose never exceeds 25 mg within a time span of 24 hours. Those who are taking SSRIs, SNRIs or other such drugs which can influence your serotonin level must be more careful; co-administration of cyclobenzaprine with such drugs can lead to excessive build-up of serotonin. If unchecked, it can result in a toxic condition.

Side effects of cyclobenzaprine – This drug may cause some adverse effects. Commonly noticed discomforts and side effects include – being in a confused state of mind, headaches, irritation, feeling dizzy, dryness of mouth or acute spells of drowsiness.

Diazepam – This medicine falls under the sub-segment of benzodiazepines; it is mainly used among those who have muscular pains or spasms along with nerve conditions. It is available as an injectable form or as an orally consumed variant. Dosages are kept at extremely low levels of less than 8 mg per day. In case of its injectable form, strength is never used more than 6 mg.

Side effects of diazepam – Typical discomforts experienced among people who take diazepam are weariness, feeling dizzy, lack of coordination, tiredness, etc. You must never take diazepam with alcohol or sedative drugs. Intake of sedative meds or anesthetic drugs can lead to loss of consciousness, or at times, fatal outcomes. So, if you are planning to undergo a surgery, you need to inform your surgical team about intake of diazepam. It is likely that your surgeon will advise discontinuation of this drug at least 10 to 15 days prior to the date of surgery.

Over the counter (OTC) muscle relaxants and their side effects

Apart from drugs that are prescribed, a few muscle relaxers are available as over the counter (OTC) meds. These include drugs such as methocarbamol – which is an antispasmodic drug, belonging to the non-benzodiazepine sub-genre. This drug is consumed orally; however, in some rare instances, its intra-muscular and intravenous versions are also used. The common dosage form is never more than 500 milligrams (mg). For some rare muscular conditions, dosage strength of more than 500 mg is recommended. But, in such cases, dosages are divided into multiple parts to avoid likely overdoses. The typical side effects of muscle relaxers taken through OTC route include frequent spells of headache, abdominal dysfunction such as indigestion, diarrhea or vomiting, feeling drowsy as well as spells of dizziness and being in a confused state of mind.

Muscle relaxers with anti-spastic and antispasmodic capabilities

Very few muscle relaxers are made with anti-spastic as well as antispasmodic properties. One such drug is tizanidine. Though it is known to have capabilities of both genres, its use is restricted to treat spastic problems associated with spinal cord or due to conditions like multiple sclerosis. These drugs are prescribed at very low dosage levels of 2 mg or 4 mg. Also, they may need to be taken once every 7 hours for better results. The typical side effects of drugs like tizanidine are difficulties to pass stools, dehydration, signs of rhinitis (runny nose, pressure in the sinus region and congestion, etc.), blurring of eyesight, etc. Some people have also reported discomforts like decrease in heart rate, feeling drowsy or dizzy, persistent spells of itchiness, frequent urges to urinate, being in a nervous frame of mind, etc.

In general, dosages of muscle relaxers depend on multiple factors; these include your age, gender, your muscular condition, presence of other ailments and how well your body responds to the initial doses of the muscle relaxer. The most common side effects one may witness include breathing problems, fainting or passing out. Both can lead to fatal outcomes if left unattended; respiratory difficulties may arise due to weakness of muscles of your lungs. On the other hand, one may faint after taking muscle relaxers along with anesthetic meds or intoxicants such as alcohol.

You need to quickly seek needful medical help upon witnessing any of these serious side effects. You can call your treating physician and pharmacist for proper directions. Those living in the US can either call 911 or a poison control center located near your place. People living in Canada are advised to reach out to Health Canada promptly, or contact the closest poison control unit located in your province.