Gastrointestinal complications of diabetes mellitus

Table 1 Classification of severity of gastroparesis

Grade 1: Mild	Symptoms easily controlled
	Regular diet/minor dietary modifications helps to maintain normal nutritional status
Grade 2: Compensated	Moderate symptoms that are reasonably controlled with prokinetics and anti-emetics
	Maintenance of nutrition with diet/lifestyle changes
	Hospitalizations-infrequent
Grade 3: Gastric failure	Refractory symptoms
	Inadequate nutrition
	Needing hospitalization for therapy and nutritional supplementation (either enteral or parenteral)
	May need surgical or endoscopic intervention or gastric "pacemaker"

Originated from Abell et al[27].

Table 2 Drugs useful in treatment of diabetic gastroparesis

Drug/drug group	Mechanism of action	Common side effects	Efficacy
Metoclopramide 10 mg 4 times/d	Anti-emetic, reduces nausea and post-prandial fullness, increases gastro-esophageal sphincter tone and improves antro-pyloro-duodenal coordination	Tardive dyskinesia, drowsiness, irritability, extrapyramidal symptoms and dystonic reactions	Symptom control in 1/3 to 2/3 of patients
Domperidone 10 -20 mg 3 times/d	Similar to metoclopramide with fewer CNS side effects due to a predominant peripheral mechanism of action	May prolong QTc interval in ECG; in turn may provoke cardiac arrhythmia	Effective in up to 60% of cases; tachyphylaxis develops in a few weeks requiring discontinuation
Erythromycin 50-250 mg thrice daily	Motilin receptor agonist. Reduces gastric emptying time	Nausea and vomiting at high doses	Modest symptom control Intravenous form can be useful in refractory vomiting
Promethazine, prochlorperazine and chlorpromazine	Mechanism of antiemesis poorly understood	Drowsiness, liver injury and extrapyramidal effects	Marginal improvement of symptoms Intramuscular chlorpromazine is very effective in refractory vomiting
Ondansetron	Central serotonin receptor (5-HT3) antagonist Inhibits vagus nerve	Extrapyramidal effect	Modest efficacy

Originated from Hasler[12]. CNS: Central nervous system; ECG: Electrocardiogram; QTc: Corrected QT interval.