Spasmolytics/antispasmodics
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MUSCLE RELAXANTS
Drugs decreasing muscle tone and muscle  contractility
skeletal muscles
smooth muscles
TERMINOLOGY
SPASMOLYTICS
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Spasmolytics/antispasmodics
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—a group of drugs with a relaxing effect on smooth muscles
—therapy of functional diseases of the GIT, GU system
—symptomatic therapy, aimed at suppressing subjective difficulties caused by incr. tone of  smooth
muscles (cramps), dyskinesia and smooth muscle hyperkinesia (hypermotility of
GIT)
—Indications: therapeutic and diagnostic examinations - endoscopy, e.g. ERCP
—reduction of motility, suppression of pain, diarrhea, convulsions, nausea, vomiting, COPD/AB
hyperactive bladder, supportive treatment in Parkinson's disease
—enteric nervous system (plexus myentericus Auerbachi), ANS, other agents (NO, ATP, VIP)

•Contraindications:
—paralytic ileus
—myasthenia gravis
—pyloric stenosis
—BPH
—pregnancy + lactation
•AE:
—constipation
—dry mouth
—(+ other anticholinergic AE)
—flatulence
—pyrosis
Spasmolytics/antispasmodics

1. Neurotropic
- parasympatholytics (atropine - not currently used as antispasmodic,  oxybutynin, solifenacin,
darifenacin, otilonium, fenpiverine, N-  butylscopolamine, trospium, tolterodine)
2. Myotropic
(drotaverin, alverin, mebeverin, pitofenon)
+ carminative, spasmoanalgesics, deflatulent agents
(dimethicone, simethicone)
+ others (NSAIDs, opioids, nitrates, antidepressants with  anticholinergic action etc.)
Classification of antispasmodics

- VNS receptors, only splanchnic smooth muscle
a) Anticholinergics / parasympatholytics
with tertiary N, lipophilic substances, via HEB (CNS AE)
—atropine – spasmolytic eff. on the GIT, obsolete
—oxybutynine – selectively for the urinary systém, I: pollakiuria,
incontinence, hyperactive urine. Bladder
—darifenacin, solifenacin – urinary bladder hyperactivity, incontinence,  pollakiuria
Neurotropic antispasmodics

b) Parasympatholytics
-quaternary N, does not pass through BBB
—otilonium – spasms of the GIT, biliary system, G-U system
—fenpiverine – combination with metamizole and pitofenone,
spasmoanalgesic system, GIT, GU, dysmenorrhea
—N-butylscopolamine – spasms of the GIT, biliary system, G-U  system, endoscopy fesoterodine,
tolterodine, trospium – functional  disorders of the GIT and GU system
—ipratropium, tiotropium – bronchodilators, often in combination  with beta2 agonists
Neurotropic antispasmodics

— oxybutynine, propiverine
•act selectively on the urinary system
IND: incontinence due to overactive bladder (after spinal cord injury)
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Combination of neurotropic/myotropic  antispasmodics

—direct effect on smooth muscles, smooth muscles in the  vessels
—Various MoA: blockade of calcium channels, activation of  potassium channels, stimulation of NO
production, increase  of cAMP/cGMP, ...
—papaverine
—originating from opium - phosphodiesterase inhibitor, visceral  spasms, colic (biliary, renal),
vasospasm
—
—drotaverine – phosphodiesterase inhibitor, gynecological  indications (dysmenorrhea, adnexitis),
smooth muscle  spasms (irritable bowel syndrome, billiary colic, bladder  tenesmas, ...), headache
of vascular etiology
Myotropic antispasmodics

—alverine – phosphodiesterase inhibition, combination with  simethicone, functional GIT
difficulties - flatulence, flatulence, IBS
—mebeverine – more MoA including local anesthetic effect, irritable  bowel syndrome, GIT spasms
—pitofenone – phosphodiesterase inhibition, combination with  metamizole and fenpiverine -
spasmoanalgesia, IBS
Myotropic antispasmodics

Other antispasmodics
—beta 3 agonist – mirabegron  IND: hyperactive bladder
—alpha 1 antagonists – alfuzosine, tamsulosine  IND: BHP
—glucagon – premedication for endoskopy
—TCA – amitriptyline (anticholinergic action)
—Ca2+ channel blockers – nifedipine
—Nitrates – esophageal motility disorders, esophageal achalasia
—opioids – pethidine
IND: acute painful spasms, biliary system spasm (rather obsolete)

—combination of antispasmodics with analgesics (metamizole,
paracetamol, opioids – codeine, tramadol, pethidine)
—i.v. admin – accelerating onset of the effect
—IND: dysmenorrhea, smooth muscle spasms with pain, obstetrics
surgery, instrumental procedures
Spasmoanalgesics