Pharmacology of prokinetic agents
Meclid activates 5-HT 4 receptors, antagonizes 5-HT3 receptors, and antagonizes central and peripheral D2 receptors to release the “dopamine brake.” It works on the stomach and proximal small bowel but has little effect on colonic motility. The pharmacokinetics of Meclid and of most other antiemetics discussed in this chapter is summarized in Table 25-4 .
Table 25-4 . Pharmacokinetics of selected antiemetic drugs
Reglan S >
In approximately 10 percent of patients given 10 mg of Reglan (Meclid) four times daily, the most commonly reported side effects included restlessness, drowsiness, fatigue and lassitude (mental weariness or lack of energy). The incidence of such adverse reactions was dependent upon dosage and duration of drug exposure.
Some adverse reactions occurred after Reglan treatment was discontinued, especially involving the nervous system. These side effects included dizziness, nervousness and headaches.
Use of Reglan, especially for longer than 12 weeks, carries the risk of developing a condition known as tardive dyskinesia (TD), a neurological disorder that involves involuntary, rapid movements of the face and body.
Depending on the person, TD symptoms may be mild and only last for a short time or they may continue indefinitely. If the condition is diagnosed early enough, changing medications may be enough. In some instances, however, it can be permanent.
Ondansetron (Zofran) vs. Meclid (Reglan): What's the difference?
- Ondansetron and Meclid are used to prevent and treat nausea and vomiting.
- Ondansetron is most often used to prevent nausea and vomiting caused by cancerchemotherapy and to prevent vomiting and nausea after surgery.
- Meclid is used to relieve heartburn symptoms with gastroesophageal reflux when certain other treatments do not work and to relieve the symptoms of slow stomach emptying in people with diabetes.
- Brand names for ondansetron include Zofran, Zofran ODT, and Zuplenz.
- Brand names for Meclid include Reglan and Metozolv ODT.
- Ondansetron and Meclid belong to different drug classes. Ondansetron is an anti-nausea medication and Meclid is a "prokinetic" drug.
- Side effects of ondansetron and Meclid that are similar include fatigue and drowsiness.
- Side effects of ondansetron that are different from Meclid include headache, feeling unwell (malaise), constipation, dizziness, diarrhea, and abnormal heart rate and rhythm.
- Side effects of Meclid that are different from ondansetron include restlessness, anxiety, insomnia, depression, and sedation.
Benzam > Meclid is the most commonly used drug in this class. It blocks type 2 dopamine receptors and 5-HT 3 serotonin receptors (when used in higher doses used to prevent CINV) in the chemoreceptor trigger zone, increases lower esophageal sphincter tone, and enhances bowel and gastric motility. The usual recommended doses are 20 to 40 mg orally every 4 to 6 hours (conventional dose) or 2 to 3 mg/kg (high dose). 64 Meclid crosses the blood-brain barrier, and side effects include extrapyramidal reactions such as acute dystonia, akathisia, and possible irreversible tardive dyskinesia, especially with prolonged use of high doses and in the elderly. Diphenhydramine or hydroxyzine can be used to antagonize the dopaminergic toxicity of Meclid. In addition, Meclid can lower the seizure threshold and increase the risk of convulsions in patients with epilepsy. 37 In the past, Meclid combined with dexamethasone was the antiemetic regimen of choice for preventing delayed CINV, 65,66 but it has largely been replaced by the use of 5-HT 3 antagonists and aprepitant.
What is the most important information I should know about Meclid:
Meclid is a prescription medication that is not FDA approved for use in veterinary medicine; however, it is a commonly accepted practice for veterinarians to use this medication in dogs and cats. Meclid is available as 5mg and 10mg scored tablets. The usual dose for dogs and cats is 0.1-0.2mg/pound every 6-8 hours. Always follow the dosage instructions provided by your veterinarian. Meclid is not for use in animals allergic to it. Call your veterinarian immediately if your pet exhibits uncontrollable movements or muscle spasms of the legs, lips, jaw, tongue, face or other body part, agitation, jitteriness, shortness of breath or insomnia. Meclid may cause drowsiness.
A few cases of neutropenia, leukopenia, or agranulocytosis, generally without clear-cut relationship to Meclid. Methemoglobinemia, in adults and especially with overdosage in neonates (see OVERDOSE). Sulfhemoglobinemia in adults.
Meclid side effects
Get emergency medical help if you have signs of an allergic reaction to Meclid: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Stop taking Meclid and call your doctor at once if you have any of these SIGNS OF A SERIOUS MOVEMENT DISORDER, which may occur within the first 2 days of treatment:
tremors or shaking in your arms or legs;
uncontrolled muscle movements in your face (chewing, lip smacking, frowning, tongue movement, blinking or eye movement); or
any new or unusual muscle movements you cannot control.
Call your doctor at once if you have:
confusion, depression, thoughts of suicide or hurting yourself;
slow or jerky muscle movements, problems with balance or walking;
mask-like appearance in your face;
anxiety, agitation, jittery feeling, trouble staying still, trouble sleeping;
swelling, feeling short of breath, rapid weight gain; or
severe nervous system reactionvery stiff (rigid) muscles, high fever, sweating, confusion, fast or uneven heartbeats, tremors, feeling like you might pass out.
Common Meclid side effects may include:
feeling drowsy or tired;
headache, confusion; or
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
What should I avoid while giving Meclid to my pet:
Do not use Preventic Flea Collar on your pet while giving this medication.
What is the dosage for Meclid?
The usual dose of Meclid for treating GERD is 10-15 mg four times daily, 30 minutes before each meal.
Gastroparesis is treated with 10 mg administered orally four times daily, 30 minutes before each meal and at bedtime.