Pharmacology Lecture Notes
Drugs Use in the Management of
Gastrointestinal Disorder II
(Antiemetic, Prokinetic & Digestant Agents)
For Set 7x/Rms 3x
By
Azi Bulus Samuel (MSc, BNSc, PgDE, HND
(PHN), RN,RM RPHN)
, Emesis (Vomiting)
Vomiting occurs due to stimulation of the emetic (vomiting) centre situ
the medulla oblongata.
The chemoreceptor trigger zone (CTZ) located in the area postrema a
nucleus tractus solitarius (NTS) are the most important relay areas for a
impulses arising in the g.i.t, throat and other viscera.
The CTZ is also accessible to bloodborne drugs, mediators, hormones,
etc. because it is unprotected by the blood-brain barrier.
Cytotoxic drugs, radiation and other g.i. irritants release 5-HT
enterochromaffin cells acts on 5-HT3 receptors present on extrinsic p
afferent neurones (PAN) of the enteric nervous system (ENS).
, These neurones connect with vagal and spinal visceral afferents t
impulses to NTS and CTZ.
Released in large quantity, 5-HT may also spill into circulation and
CTZ via the vascular route.
5-HT may as well be released from platelets by inflammatory mediato
5-HT is not the only mediator of such signals: many peptides, e.g. sub
P and other messengers are also involved.
, CTZ and NTS express a variety of receptors, e.g. histamine H1, dopam
serotonin 5-HT3, cholinergic M, neurokinin NK1 (activated by subst
cannabinoid CB1 and opioid μ receptors through which the emetic sig
relayed and which could be targets of antiemetic drug action.
The vestibular apparatus generates impulses when body is rot
equilibrium is disturbed or when ototoxic drugs act.
These impulses reach the vomiting centre mainly relayed from the cer
and utilize muscarinic as well as H1 receptors.
Various unpleasant sensory stimuli such as bad odour, ghastly sight, sev
as well as fear, recall of an obnoxious event, anticipation of an emetic
(repeat dose of cisplatin) cause nausea and vomiting through higher cen
Drugs Use in the Management of
Gastrointestinal Disorder II
(Antiemetic, Prokinetic & Digestant Agents)
For Set 7x/Rms 3x
By
Azi Bulus Samuel (MSc, BNSc, PgDE, HND
(PHN), RN,RM RPHN)
, Emesis (Vomiting)
Vomiting occurs due to stimulation of the emetic (vomiting) centre situ
the medulla oblongata.
The chemoreceptor trigger zone (CTZ) located in the area postrema a
nucleus tractus solitarius (NTS) are the most important relay areas for a
impulses arising in the g.i.t, throat and other viscera.
The CTZ is also accessible to bloodborne drugs, mediators, hormones,
etc. because it is unprotected by the blood-brain barrier.
Cytotoxic drugs, radiation and other g.i. irritants release 5-HT
enterochromaffin cells acts on 5-HT3 receptors present on extrinsic p
afferent neurones (PAN) of the enteric nervous system (ENS).
, These neurones connect with vagal and spinal visceral afferents t
impulses to NTS and CTZ.
Released in large quantity, 5-HT may also spill into circulation and
CTZ via the vascular route.
5-HT may as well be released from platelets by inflammatory mediato
5-HT is not the only mediator of such signals: many peptides, e.g. sub
P and other messengers are also involved.
, CTZ and NTS express a variety of receptors, e.g. histamine H1, dopam
serotonin 5-HT3, cholinergic M, neurokinin NK1 (activated by subst
cannabinoid CB1 and opioid μ receptors through which the emetic sig
relayed and which could be targets of antiemetic drug action.
The vestibular apparatus generates impulses when body is rot
equilibrium is disturbed or when ototoxic drugs act.
These impulses reach the vomiting centre mainly relayed from the cer
and utilize muscarinic as well as H1 receptors.
Various unpleasant sensory stimuli such as bad odour, ghastly sight, sev
as well as fear, recall of an obnoxious event, anticipation of an emetic
(repeat dose of cisplatin) cause nausea and vomiting through higher cen
