This document discusses anti-spasmodic drugs, which are smooth muscle relaxants used to prevent spasms in the gastrointestinal tract and urinary bladder. It describes two types - anticholinergics/antimuscarinics which block acetylcholine receptors, and non-anticholinergic smooth muscle relaxants. Specific drugs discussed include hyoscine butylbromide, dicyclomine, and drotaverine. These drugs are used to treat conditions involving smooth muscle spasms like irritable bowel syndrome, abdominal pain, and urinary incontinence. Their mechanisms of action and side effect profiles are also outlined.

1. Anti-Spasmodics
Dr. Saroj Suwal

2. Anti Spasmodic
 Are the Smooth muscle relaxants in GI
 prevent spasms of the stomach, intestine or urinary
bladder
 are given for abdominal pain, IBS symptoms

3. Anti-spasmodic drugs classification
Two types :
• Antimuscarinics/Anticholinergics :
• Hyoscine Butylbromide, Atropine, Dicyclomine,
Propantheline
•Smooth muscle relaxants: (Non
anticholinergics)
Drotaverine, Alverine, Mebeverine,
Peppermint oil

4. ANTI CHOLINERGIC
 block the neurotransmitter acetylcholine in CNS and PNS.
 combine reversibly with muscarinic cholinergic receptors thus
preventing access of neurotransmitter acetylcholine
 TWO TYPES
ANTI MUSCARINIC
ANTI NICOTINIC

8. Antimuscarinic drugs
block cholinergic transmission at
parasympathetic postganglionic nerve
endings → cause smooth muscle to
relax.
 dicyclomine and propantheline are
probably the most useful in IBS,
Avoid pt with GERD→ can
worsen the conditions

9. smooth muscle relaxants
Alverine and peppermint oil also
have direct smooth muscle
relaxing activity.
peppermint oil block calcium
influx thus cause smooth muscle
relax

10. Common Uses
• For spasm (colic), bloating and abdominal pain
• To reduce the movement ( motility) of the intestine
• Overactive bladder
• Movement problems in Parkinson's disease
• Diarrhea
• Motion sickness
• Nausea and/or vomiting
• Muscle spasms
• Chronic obstructive pulmonary disease (COPD)
• Asthma

11. MECHANISM OF ACTION :
Food in
GUT Relax &
contract
of
muscles
in gut.
Pain
and
bloating
Anti muscarinic
attach to the
muscarinic
receptors
Relax the
smooth
muscle in
intestine.

12. Hyoscine Butylbromide -Buscopan
Also known as scopolamine butylbromide
MOA:
• has anticholinergic action.
• Has high affinity for muscarinic receptors located on the
smooth-muscle cells of the GI tract exerts a smooth-muscle
relaxing/spasmolytic effect.

13. Indications
• crampy abdominal pain
• esophageal spasms
• renal colic
• bladder spasms
• also used to improve respiratory secretions at the
end of life
• Can taken by Oral , im or IV
• (Dosage
• 10mg oral x TDS, 20mg/ml Inj x TDS)

14. Side effects
• sleepiness,
• vision changes,
• dry mouth,
• rapid heart rate,
• triggering of glaucoma and
• severe allergies

15. Dicyclomine:
 muscarinic antagonist used as an antispasmodic
and in urinary incontinence
Has direct smooth muscle relaxant
action
Has weak anti cholinergic
Exerts anti spasmodic action
Also has anti-emetic
property

16. Indications:
Morning sickness
Motion sickness
Dysmenorrhoea
Irritable bowel disease
Dose:
20 mg oral/i.m children 5-10mg

17. Contraindications:
 Paralytic ileus
 Myasthenia gravis
 Pyloric stenosis
 Enlargement of the prostate
 Pregnancy
 Lactating mother

18. ADRs
 Flatulence
 bloating(wind)
 Heart burn
 Constipation
 Dry mouth

19. Smooth muscle relaxants: (Non anticholinergics)
Are direct smooth muscle relaxants
Drotaverine

20. Drotaverine:
❑ non anticholinergic smooth muscle relaxant
❑ Exerts anti spasmodic action
❑ Used orally nd
Injections
❑Eg. Tab. Drotin
40 mg ,

21. MOA
Drotaverine
Inhibits
phosphodiest
erase IV
decrease
cAMP/cGMP
and Ca level smooth
muscle
relaxation

22. Indications:
 Intestinal, biliary, renal colic
 Irritable bowel syndrome
 Uterine spasm ( dysmenorrhea)
 headache,
 also used to relieve cervical spasm during labor.
 Dose
 Drotin 40-80 mg tds
ADR
 Headache Dizziness Constipation
 Flushing
 Fall in BP can occur on iv inj

23. Contraindications
 Allergy
 Sever liver/kidney damage
 Heart Failure