Actions of Metoclox in details
Pharmacotherapeutic Group: Antiemetic.
Pharmacology: Pharmacodynamics: Mechanism of Action: Metoclox has antiemetic, antinauseant and gastrokinetic activity. It stimulates motility of the upper gastrointestinal tract without stimulating gastric, biliary or pancreatic secretions. The rate of gastric emptying is increased due to increased peristalsis of the jejunum and duodenum. The tone and amplitude of gastric contractions are increased with relaxation of the pyloric sphincter and duodenal bulb. These effects combine to result in decreased intestinal transit time. The effect of Metoclox on motility is not dependent on intact vagal innervation, but it can be abolished by anticholinergic drugs. Metoclox has little, if any effect on the motility of the colon or bladder. Metoclox also exhibits dopamine-antagonist activity and consequently produces sedation and rarely, other extrapyramidal reactions. It may have serotonin receptor (5-HT3) antagonist properties. Metoclox inhibits the central and peripheral effects of apomorphine, induces release of prolactin and produces a transient increase in circulating aldosterone levels.
Pharmacokinetics: Following IV administration, the onset of action is within 1-3 min and after IM administration, this interval is extended to 10-15 min. The effect usually lasts from 1-2 hrs.
About 80% of the drug is excreted in the urine in the first 24 hrs after administration. Approximately ½ is unchanged Metoclox and ½ is the glucuronide and sulphate conjugate. Metabolism mainly occurs in the liver and elimination t½ may vary from 2.5-6 hrs. Impaired renal function results in a reduced clearance and an increased t½, up to 15 hrs. Plasma protein-binding is 13-22%.
How should I take Metoclox?
Take Metoclox exactly as prescribed by your doctor. Metoclox is usually taken for only 4 to 12 weeks. Follow the directions on your prescription label.
NEVER TAKE Metoclox IN LARGER AMOUNTS THAN RECOMMENDED, OR FOR LONGER THAN 12 WEEKS.
High doses or long-term use of Metoclox can cause a serious movement disorder that may not be reversible. Symptoms of this disorder include uncontrollable muscle movements of your lips, tongue, eyes, face, arms, or legs. The longer you take Metoclox, the more likely you are to develop a serious movement disorder. The risk of this side effect is higher in women, diabetics, and older adults.
Take Metoclox 30 minutes before eating. Metoclox is usually taken before meals and at bedtime. Your doctor may want you to take the medication as needed only with meals that usually cause heartburn. Follow your doctor's instructions.
Measure the liquid medicine with a special dose-measuring spoon or cup, not a regular table spoon. If you do not have a dose-measuring device, ask your pharmacist for one.
Do not take two different forms of Metoclox (such as tablets and oral syrup) at the same time.
Store Metoclox at room temperature away from moisture and heat. Keep the bottle tightly closed when not in use. After you stop taking Metoclox, you may have unpleasant withdrawal symptoms such as headache, dizziness, or nervousness. Talk to your doctor about how to avoid withdrawal symptoms when stopping the medication.
Metoclox administration
Take exactly as prescribed by your doctor. Metoclox is usually taken for only 4 to 12 weeks. Follow the directions on your prescription label.
NEVER TAKE Metoclox IN LARGER AMOUNTS THAN RECOMMENDED, OR FOR LONGER THAN 12 WEEKS. High doses or long-term use of Metoclox can cause a serious movement disorder that may not be reversible. Symptoms of this disorder include uncontrollable muscle movements of your lips, tongue, eyes, face, arms, or legs. The longer you take Metoclox, the more likely you are to develop a serious movement disorder. The risk of this side effect is higher in women, diabetics, and older adults.
Take Metoclox 30 minutes before eating. Metoclox is usually taken before meals and at bedtime. Your doctor may want you to take the medication as needed only with meals that usually cause heartburn. Follow your doctor's instructions.
Measure the liquid medicine with a special dose-measuring spoon or cup, not a regular table spoon. If you do not have a dose-measuring device, ask your pharmacist for one.
To take Metoclox orally disintegrating tablet (ODT):
- Keep the tablet in its bottle or blister pack until you are ready to take the medicine. Make sure your hands are dry before handling a tablet. If the tablet breaks or melts in your hand, throw it away and use a new tablet.
- Place the tablet on your tongue. It will begin to melt right away. Do not swallow the tablet whole. Allow it to melt in your mouth without chewing.
- Swallow several times as the tablet melt. You do not need to drink liquid to help the tablet melt.
Do not take two different forms of Metoclox (such as tablets and oral syrup) at the same time.
Store at room temperature away from moisture and heat. Keep the bottle tightly closed when not in use.
After you stop taking Metoclox, you may have unpleasant withdrawal symptoms such as headache, dizziness, or nervousness. Talk to your doctor about how to avoid withdrawal symptoms when stopping the medication.
Metoclox pharmacology
Mechanism of Action
Metoclox stimulates motility of the upper gastrointestinal tract without stimulating gastric, biliary, or pancreatic secretions. Its mode of action is unclear. It seems to sensitize tissues to the action of acetylcholine. The effect of Metoclox on motility is not dependent on intact vagal innervation, but it can be abolished by anticholinergic drugs.
Metoclox increases the tone and amplitude of gastric (especially antral) contractions, relaxes the pyloric sphincter and the duodenal bulb, and increases peristalsis of the duodenum and jejunum resulting in accelerated gastric emptying and intestinal transit. It increases the resting tone of the lower esophageal sphincter. It has little, if any, effect on the motility of the colon or gallbladder.
The antiemetic properties of Metoclox appear to be primarily a result of its antagonism of central and peripheral dopamine receptors. Dopamine produces nausea and vomiting by stimulation of the medullary chemoreceptor trigger zone (CTZ), and Metoclox blocks stimulation of the CTZ by agents like 1-dopa or apomorphine which are known to increase dopamine levels or to possess dopamine-like effects. Metoclox also abolishes the slowing of gastric emptying caused by apomorphine.
Like the phenothiazines and related drugs, which are also dopamine antagonists, Metoclox produces sedation and may produce extrapyramidal reactions, although these are comparatively rare. Metoclox inhibits the central and peripheral effects of apomorphine, induces release of prolactin and causes a transient increase in circulating aldosterone levels, which may be associated with transient fluid retention.
Pharmacodynamics
The onset of pharmacological action of Metoclox is 1 to 3 minutes following an intravenous dose, 10 to 15 minutes following intramuscular administration, and 30 to 60 minutes following an oral dose; pharmacological effects persist for 1 to 2 hours.
In patients with gastroesophageal reflux and low LESP (lower esophageal sphincter pressure), single oral doses of Metoclox produce dose-related increases in LESP. Effects begin at about 5 mg and increase through 20 mg (the largest dose tested). The increase in LESP from a 5 mg dose lasts about 45 minutes and that of 20 mg lasts between 2 and 3 hours. Increased rate of stomach emptying has been observed with single oral doses of 10 mg.
Pharmaeokincties
Absorption
Metoclox is well absorbed. Relative to an intravenous dose of 20 mg, the absolute oral bioavailability of Metoclox is 80% ± 15.5% as demonstrated in a crossover study of 18 subjects. Peak plasma concentrations occur at about 1 to 2 hr after a single oral dose. Similar time to peak is observed after individual doses at steady state.
In a single dose study of 12 subjects, the area under the drug concentration-time curve increases linearly with doses from 20 to 100 mg. Peak concentrations increase linearly with dose; time to peak concentrations remains the same. Linear kinetic processes adequately describe the absorption of Metoclox.
Distribution
The drug is not extensively bound to plasma proteins (about 30%). The whole body volume of distribution is high (about 3.5 L/kg) which suggests extensive distribution of drug to the tissues.
Excretion
In a single dose study of 12 subjects with doses from 20 to 100 mg, whole body clearance is unchanged; and the elimination rate remains the same. The mean elimination half-life of Metoclox is approximately 7 hr after administration of Metoclox™. Linear kinetic processes adequately describe the elimination of Metoclox.
Approximately 85% of the radioactivity of an orally administered dose appears in the urine within 72 hr. Of the 85% eliminated in the urine, about half is present as free or conjugated Metoclox.
| Adult Pharmakokinetic Data | |
| Parameter | Value |
| Vd (L/kg) | ~3.5 |
| Plasma Protein Binding | ~ 30% |
| t½ (hr) | ~ 7 |
Oral Bioavailability | 80% ± 15.5% |
Special Populations
Renal Insufficiency
Renal impairment affects the clearance of Metoclox. In a study with patients with varying degrees of renal impairment, a reduction in creatinine clearance was correlated with a reduction in plasma clearance, renal clearance, non-renal clearance, and increase in elimination half-life. The kinetics of Metoclox in the presence of renal impairment remained linear however. The reduction in clearance as a result of renal impairment suggests that adjustment downward of maintenance dosage should be done to avoid drug accumulation.
Pediatric Patients
In pediatric patients, the pharmacodynamics of Metoclox following oral and intravenous administration are highly variable and a concentration-effect relationship has not been established.
There are insufficient reliable data to conclude whether the pharmacokinetics of Metoclox in adults and the pediatric population are similar. Although there are insufficient data to support the efficacy of Metoclox in pediatric patients with symptomatic gastroesophageal reflux (GER) or cancer chemotherapy-related nausea and vomiting, its pharmacokinetics have been studied in these patient populations.
In an open-label study, six pediatric patients (age range, 3.5 weeks to 5.4 months) with GER received Metoclox 0.15 mg/kg oral solution every 6 hours for 10 doses. The mean peak plasma concentration of Metoclox after the tenth dose was 2-fold (56.8 µg/L) higher compared to that observed after the first dose (29 µg/L) indicating drug accumulation with repeated dosing. After the tenth dose, the mean time to reach peak concentrations (2.2 hr), half-life (4.1 hr), clearance (0.67 L/h/kg), and volume of distribution (4.4 L/kg) of Metoclox were similar to those observed after the first dose. In the youngest patient (age, 3.5 weeks), Metoclox half-life after the first and the tenth dose (23.1 and 10.3 hr, respectively) was significantly longer compared to other infants due to reduced clearance. This may be attributed to immature hepatic and renal systems at birth.
Single intravenous doses of Metoclox 0.22 to 0.46 mg/kg (mean, 0.35 mg/kg) were administered over 5 minutes to 9 pediatric cancer patients receiving chemotherapy (mean age, 11.7 years; range, 7 to 14 yr) for prophylaxis of cytotoxic-induced vomiting. The Metoclox plasma concentrations extrapolated to time zero ranged from 65 to 395 µg/L (mean, 152 µg/L). The mean elimination half-life, clearance, and volume of distribution of Metoclox were 4.4 hr (range, 1.7 to 8.3 hr), 0.56 L/h/kg (range, 0.12 to 1.20 L/h/kg), and 3.0 L/kg (range, 1.0 to 4.8 L/kg), respectively.
In another study, nine pediatric cancer patients (age range, 1 to 9 yr) received 4 to 5 intravenous infusions (over 30 minutes) of Metoclox at a dose of 2 mg/kg to control emesis. After the last dose, the peak serum concentrations of Metoclox ranged from 1060 to 5680 µg/L. The mean elimination half-life, clearance, and volume of distribution of Metoclox were 4.5 hr (range, 2.0 to 12.5 hr), 0.37 L/h/kg (range, 0.10 to 1.24 L/h/kg), and 1.93 L/kg (range, 0.95 to 5.50 L/kg), respectively.
References
- NCIt. "Metoclopramide: NCI Thesaurus (NCIt) provides reference terminology for many systems. It covers vocabulary for clinical care, translational and basic research, and public information and administrative activities.". https://ncit.nci.nih.gov/ncitbrowser... (accessed September 17, 2018).
- EPA DSStox. "Metoclopramide: DSSTox provides a high quality public chemistry resource for supporting improved predictive toxicology.". https://comptox.epa.gov/dashboard/ds... (accessed September 17, 2018).
Reviews
The results of a survey conducted on ndrugs.com for Metoclox are given in detail below. The results of the survey conducted are based on the impressions and views of the website users and consumers taking Metoclox. We implore you to kindly base your medical condition or therapeutic choices on the result or test conducted by a physician or licensed medical practitioners.User reports
Consumer reported administration
No survey data has been collected yetConsumer reviews
There are no reviews yet. Be the first to write one! |
Information checked by Dr. Sachin Kumar, MD Pharmacology
