Name of the Promotility Drug Agents
- Metoclopramide
- Urecholine (bethanechol)
1.Metoclopramide
| Metoclopramide |
| Availability: Injectable solution ,5mg/mL syrup 5mg/5mL ,10mg/10mL tablet 5mg ,10mg Dispersible tablets 5mg ,10mg |
| Indications and Dosages: To treat diabetic gastroparesis ORAL SOLUTION, ORAL SOLUTION CONCENTRATE, TABLETS Adults and adolescents. 10 mg 30 min before meals and at bedtime up to q.i.d I.V. OR I.M. INJECTION Adults and adolescents. 10 mg t.i.d. or q.i.d. for severe symptoms; dosage adjusted as needed. To treat gastroesophageal reflux disease ORAL SOLUTION, ORAL SOLUTION CONCENTRATE, TABLETS Adults and adolescents. 10 to 15 mg 30 min before meals and at bedtime. To prevent chemotherapy-induced vomiting I.V. INFUSION Adults and adolescents. 3 mg/kg before chemotherapy and then 0.5 mg/kg/hr for 8 hr. I.V. INJECTION Adults and adolescents. 1 to 2 mg/kg 30 min before chemotherapy and then repeated every 2 to 3 hr, as needed. Children. 1 mg/kg as a single dose, repeated in 1 hr. Maximum: 2 mg/kg. To prevent postoperative nausea and vomiting I.M. INJECTION Adults and adolescents. 10 to 20 mg near end of procedure. |
Mechanism of Action :
Antagonizes the inhibitory effect of dopamine on GI smooth muscle. This causes gastric contraction, which promotes gastric emptying and peristalsis, thus reducing gastroesophageal reflux. Metoclopramide also blocks dopaminergic receptors in the chemoreceptor trigger zone, preventing nausea and vomiting.
Contraindications :
Concurrent use of butyrophenones, phenothiazines, or other drugs that may cause extrapyramidal reactions; GI hemorrhage, mechanical obstruction, or perforation; hypersensitivity to metoclopramide or its components; pheochromocytoma; seizure disorders
Pharmacokinetics
- Metabolized by liver
- Metabolites: Metoclopramide glucuronides, metoclopramide sulphates, amino acetic acid (inactive)
- Half-life (IV/IM): 5-6hr (adults); 4 hr (children)
- Dialyzable: Not significant; dose adjustment after dialysis unnecessary
- Total body clearance: 0.53-0.55 L/hr/kg (prolonged in neonates as compared with adults)
- Excretion: Primarily urine (85%)
Administration
- IV Administration
- NS is preferred diluent because drug is most stable in this solution
- Dose ≤10 mg: IV push over 1-2 minutes
- Dose >10 mg: Dilute in 50 mL D5W or NS, and infuse over at least 15 minutes
- Protect from light
Adverse Reactions
- CNS: Agitation, anxiety, depression, dizziness, drowsiness, extrapyramidal reactions (motor restlessness, parkinsonism, tardive dyskinesia), fatigue, headache, insomnia, irritability, lassitude, neuroleptic malignant syndrome, panic reaction, restlessness
- CV: AV block, fluid retention, heart failure, hypertension, hypotension, supraventricular tachycardia
- EENT: Dry mouth
- ENDO: Galactorrhea, gynecomastia
- GI: Constipation, diarrhea, nausea
- GU: Menstrual irregularities
- HEME: Agranulocytosis
- SKIN: Rash
- Other: Restless leg syndrome
Nursing Considerations
- Use metoclopramide cautiously in patients with hypertension because it may increase catecholamine levels
- Monitor patient with NADH-cytochrome b5 reductase deficiency because metoclopramide increases risk of methemoglobinemia and sulfhemoglobinemia, and patient can’t receive methylene blue.
- Assess patient for signs of intestinal obstruction, such as abnormal bowel sounds, diarrhea, nausea, and vomiting, before administering metoclopramide. Notify prescriber if you detect them.
- For I.V. use, you need not dilute doses of 10 mg or less. Give drug over 1 to 2 minutes. For doses larger than 10 mg, dilute in 50 ml normal saline solution, half-normal (0.45) saline solution, D5W, or lactated Ringer’s solution and infuse over at least 15 minutes.
- Avoid rapid I.V. delivery because it may cause anxiety, restlessness, and drowsiness.
- Monitor patient, especially one with heart failure or cirrhosis, for possible fluid retention or volume overload due to transient increase in plasma aldosterone level.
- Monitor patient closely for neuroleptic malignant syndrome, a rare but potentially fatal disorder characterized by hyperthermia, muscle rigidity, altered level of consciousness, irregular pulse or blood pressure, tachycardia, diaphoresis, and arrhythmias.
- Store drug in a light-resistant container; discard if discolored or contains particulate.
Patient Teaching
- Advise against activities that require alertness for about 2 hours after each dose.
- Urge patient to avoid alcohol and CNS depressants while taking metoclopramide. They may increase CNS depression.
- Tell patient to immediately report involuntary movements of face, eyes, tongue, or hands, including lip smacking, chewing, puckering of mouth, frowning, scowling, sticking out tongue, blinking, moving eyes, or shaking arms and legs.
- Explain that stopping metoclopramide may cause withdrawal symptoms that include dizziness, nervousness, and headache.
2.Urecholine (bethanechol)
| Urecholine (bethanechol) |
| Availability: Tablets: 5 mg, 10 mg, 25 mg, 50 mg |
| Indications and dosages Postpartum and postoperative nonobstructive urinary retention; urinary retention caused by neurogenic bladder Adults: 10 to 50 mg P.O. three to four times daily; dosage may be determined by giving 5 or 10 mg q hour until response occurs, or a total of 50 mg has been given. |
Mechanism of Action
Stimulates parasympathetic nervous system and cholinergic receptors, leading to increased muscle tone in bladder and increased frequency of ureteral peristaltic waves. Also stimulates gastric motility, increases gastric tone, and restores rhythmic GI peristalsis.
Administration
Give drug on empty stomach 1 hour before or 2 hours after a meal to help prevent nausea and vomiting.
Pharmacokinetics
Onset: 30-60 min
Duration: Up to 6 hr
Absorption: Variable
Contraindications :
- Hypersensitivity to drug
- GI or GU tract obstruction
- Hyperthyroidism
- Active or latent asthma
- Bradycardia
- Hypotension
- Atrioventricular conduction defects
- Coronary artery disease
- Seizure disorders
- Parkinsonism
- Peptic ulcer disease
Precautions:
- Sensitivity to cholinergics or their effects and tartrazine (some products)
- Pregnant or breastfeeding patients
- Children.
Adverse reactions
- CNS: headache, malaise, seizures
- CV: bradycardia, hypotension, heart block, syncope with cardiac arrest
- EENT: excessive lacrimation, miosis
- GI: nausea, vomiting, diarrhea, abdominal discomfort, belching
- GU: urinary urgency
- Respiratory: increased bronchial secretions, bronchospasm
- Skin: diaphoresis, flushing Other: hypothermia
Patient monitoring
- Monitor blood pressure. Be aware that hypertensive patients may experience sudden blood pressure drop.
- Stay alert for orthostatic hypotension, a common adverse effect.
- Monitor fluid intake and output and residual urine volume
Patient teaching
- Tell patient that drug is usually effective within 90 minutes of administration.
- Advise patient to take drug on empty stomach 1 hour before or 2 hours after a meal to avoid GI upset.
- Instruct patient to move slowly when sitting up or standing, to avoid dizziness or light-headedness from blood pressure decrease.
- As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, and herbs mentioned above.
REFERENCES
- Robert Kizior, Keith Hodgson, Saunders Nursing Drug handbook,1st edition 2024, Elsevier Publications. ISBN-9780443116070
- McGraw Hill- Drug Handbook, Seventh Edition, 2013, McGraw Hill Education Publications,9780071799430.
- April Hazard, Cynthia Sanoski, Davi’s Drug Guide for Nurses -Sixteenth Edition 2019, FA Davis Company Publications,9780803669451.
- Jones and Bartlet, Pharmacology for Nurses, Second Edition, 2020, Jones and Bartlet Learning Publications, ISBN 9781284141986.
- Nursebro.com, Search – Nursebro
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