Workshop on Pharmacology of hearing and speech sciences

1. Drug Induced Swallowing
Disorders
Dr. Ghulam Saqulain
Head Of Department of ENT
Capital Hospital

2. Stages of Swallowing:
 The three stages of swallowing are:
1. Oral
1. The act of taking food, chewing it, mixing it with
saliva, and forming it into a bolus.
2. Controlling the bolus and transporting it to the
back of the mouth.
2. Pharyngeal- initiating the swallow reflex in a
timely manner which is normally 1 second.
3. Esophageal- the food enters the esophagus, the
passageway to the stomach.

3. Oral Preparatory PhaseOral Preparatory Phase
Break down foodBreak down food
Mix with salivaMix with saliva
Prevent premature escape into pharynxPrevent premature escape into pharynx
Oral PhaseOral Phase
Tongue elevates ant to postTongue elevates ant to post
Tongue forms central grooveTongue forms central groove
Labial andLabial and buccalbuccal sealseal
Begins when tongue moves bolusBegins when tongue moves bolus posteriorlyposteriorly,,
and ends when bolus passes anterior pillar ofand ends when bolus passes anterior pillar of faucesfauces
Voluntary controlVoluntary control -- ( XII )( XII )

4. Pharyngeal PhasePharyngeal Phase
Begins when bolus passes anterior pillar orBegins when bolus passes anterior pillar or faucesfauces
Ends when bolus passes through upper oesophageal sphincter intoEnds when bolus passes through upper oesophageal sphincter into oesophagusoesophagus
Velum elevates and contracts, closing nasal passage, bolus propeVelum elevates and contracts, closing nasal passage, bolus propelled through pharynx,lled through pharynx,
larynx closed and elevated, respiration inhibited, upper oesophalarynx closed and elevated, respiration inhibited, upper oesophageal sphincter relaxesgeal sphincter relaxes
Involuntary controlInvoluntary control –– ( IX, X, XII )( IX, X, XII )

5. OesophagealOesophageal PhasePhase
Begins when bolus entersBegins when bolus enters oesophagusoesophagus
Ends when bolus passes through lowerEnds when bolus passes through lower oesophagealoesophageal sphincter into stomach 8sphincter into stomach 8--
20 seconds later20 seconds later
Sequential peristaltic wave propels bolusSequential peristaltic wave propels bolus
Relaxation of lowerRelaxation of lower oesophagealoesophageal sphinctersphincter
Involuntary controlInvoluntary control –– ( X )( X )

6. 6

7. Dysphagia
Defined as difficulty in swallowing
As part of :
 Neurological disorders
 Head and neck cancers
 Gastroentrologic Conditions
 Many drugs
 Misc. Conditions

8. Drug Induced Dysphagia
 Drug-induced dysphagia can be classified into one
of three categories:
 dysphagia as a side effect,
 dysphagia as a complication of therapeutic action,
 and medication-induced esophageal injury.

9.  Drugs impair swallowing by:
 Inducing a mechanical obstruction (mechanical
dysphagia)
 dysphagia as a complication of therapeutic action,
 and medication-induced esophageal injury.
 Affecting neuromuscular control of swallowing
(Neurogenic dysphagia)
 dysphagia as a side effect
(Note: Often resolves spontaneously
Sometimes complications occur e.g., esophageal stricture,
ulceration, bleeding, aspiration pnemonia, weight loss etc)

10. Mechanical Dysphagia
 Risk Factors For Mechanical Dysphagia
 Ingesting small amount of fluid with drug
 Assuming recumbent position following drug intake
 Oesophageal injury following NG intubation
 Oesophagus at the level of aortic arch most vulnerable to
contact by acid producing drugs (with pH less than 3) such
as tetracyclines, doxycycline, vitamin C and ferrous sulphate
 Enlarged left atrium.

11. A. Medications that can cause
esophageal injury and increase risk
 Some medications can cause dysphagia because of injury
to the esophagus caused by local irritation/chemical
irritation/oesophagitis

12.  Other medications such as high dose steroids and
chemotherapeutic (anti-cancer) preparations may
cause muscle wasting or damage to the
esophagus and may suppress the immune system
making the person susceptible to infection.
Reference: Balzer, KM, PharmD, “Drug-Induced Dysphagia”, International Journal of MS Care, page 6, Volume 2 Issue 1,
March 2000. (http://www.mscare.com/a003/page_06.htm)

13.  Drug lodging in Oesophagus and causing
mechanical obstruction – less frequent

14. Neurogenic Dysphagia
 Drugs can cause weakness of muscles involved in
swallowing or incoordination of the swallowing
process

15. A. Dysphagia as a complication of the
therapeutic action of the medication
 Medications that depress the Central Nervous System
(CNS) can decrease awareness and voluntary muscle
control that may affect swallowing

16.  Drugs that decrease oesophageal motility (Anticholinergic
properties that inhibit the activity of the striated muscle
of the pharynx, upper esophageal sphincter, esophageal
muscle incoordination, decreased esophageal parastalsis)
 E.g, clonazepam, molindrone/benztropine
combination, thiothixene/benztropine combination-
inhibit coordination of pharyngeal and laryngeal
phases of swallowing –

17.  Tardive dyskinesia is a disorder that involves
involuntary movements especially of the lower
face including persistent involuntary tongue
movements which prevent normal swallowing.
Tardive means "delayed" and dyskinesia means
"abnormal movement."
 The drugs that most commonly cause this
disorder are older antipsychotic drugs,
including:
Chlorpromazine, Fluphenazine, Haloperidol, Trifluoperazine

18.  Other drugs, similar to these antipsychotic
drugs, that can cause tardive dyskinesia
include:
Flunarizine (Sibelium), Metoclopramide, Prochlorperazine
 Newer antipsychotic drugs seem less likely to
cause tardive dyskinesia

19. B.Dysphagia as a side effect of
medication
 Medications that affect the smooth and striated muscles
of the esophagus that are involved in swallowing may
cause dysphagia.
 Discontinuation results in resolution of dysphagia.

20.  Botulinum toxin produces dysphagia in 29-57%
cases injected in the cervical muscles for
torticollis.

21.  Medications that cause dry mouth (xerostomia) may
interfere with swallowing by impairing the person’s ability
to move food

22.  Antipsychotic/ Neuroleptic medications given for
treatment of psychiatric disorders may affect swallowing
as many of them produce dry mouth and some of them
can cause movement disorders that impact the muscles of
the face and tongue which are involved in swallowing and
can also result in induction of pharyngeal-laryngeal
dystonia.
 They can also result in speaking and breathing difficulty.

23.  Respond to discontinuation and anticholinergic drugs like
benztropine, glycopyronium and diphenhydramine.

24.  Local anesthetics such as Novocain which is often
used for dental work may temporarily cause a loss
of sensation that may affect swallowing before it
wears off

25.  Broad-spectrum antibiotics and
chemotherapeutic agents may cause secondary
viral ulceration or fungal infections

26.  Stevens-Johnson syndrome is a more serious
complications of antibiotic therapy with an acute
erosive pharyngitis/ oesophagitis as well as
delayed oesophageal strictures

27.  Management:
 Discontinuation of therapy
 Supportive treatment: limiting oral intake,
administration of analgesics and
 Medical and surgical management of
complications