MEFTAL-SPAS TABLETS

Indications

• Irritable bowel syndrome
• Functional gastrointestinal disorders
• Spasm of the gastrointestinal tract

Dosage

Children: Refer to the BNF for Children for appropriate pediatric dosing guidelines.

Adults: Typically, dicyclomine is administered in doses of 20-40 mg orally, taken 4 times daily, or 10-20 mg by intramuscular injection. Dicyclomine should not be given intravenously.

Mechanism of action

Dicyclomine exerts its effects through direct antimuscarinic activity at M1, M2, and M3 receptors, along with non-competitive antagonism of bradykinin and histamine. This results in a relaxation of smooth muscle, particularly in the ileum, leading to decreased contractions and alleviation of spasms. Its major action is a non-specific direct relaxant effect on smooth muscle rather than a competitive antagonism of acetylcholine.

Pharmacodynamics

Dicyclomine is classified as an anticholinergic drug, which is effective in relaxing smooth muscle in the intestines. Its onset of action provides symptomatic relief in conditions characterized by gastrointestinal spasm and discomfort. The drug is typically dosed multiple times throughout the day, reflecting its moderate duration of action.

Pharmacokinetics

Dicyclomine is absorbed after oral administration, with peak plasma concentrations usually occurring within 1 to 2 hours. It undergoes hepatic metabolism, and its metabolites are excreted primarily in the urine. The half-life of dicyclomine varies but is generally around 1-2 hours, which supports the need for multiple daily dosing.

Contra-indications

• Glaucoma
• Myasthenia gravis
• Severe ulcerative colitis
• Obstructive uropathy
• Severe hepatic impairment

Adverse effects

• Dry mouth
• Dizziness
• Drowsiness
• Nausea
• Constipation
• Blurred vision
• Tachycardia

Interactions

• Other anticholinergic drugs may increase the risk of side effects
• CNS depressants may enhance drowsiness
• Antacids may affect absorption

Precautions

• Use with caution in patients with urinary retention
• May exacerbate existing gastrointestinal obstruction
• Caution in elderly patients due to increased sensitivity to anticholinergics
• Monitor for signs of overdose, especially in children

Pregnancy

Dicyclomine should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Consult healthcare professionals for guidance.

Breast-feeding

Dicyclomine may pass into breast milk. Caution is advised when administered to nursing women.

Storage

Store at room temperature, away from moisture and heat. Keep out of reach of children.

Formulations

• Oral tablet (20 mg, 40 mg)
• Injectable solution (10 mg/2 mL, 20 mg/2 mL)

Indications

• Mild to moderate pain
• Dysmenorrhea
• Postoperative pain
• Osteoarthritis
• Rheumatoid arthritis

Dosage

Children: For

Adults: The usual adult dose is 500 mg initially, followed by 250 mg every 8 hours as needed. The maximum daily dose should not exceed 2000 mg.

Mechanism of action

Mefenamic acid exerts its therapeutic effect by inhibiting the cyclooxygenase (COX) enzymes, which are responsible for the conversion of arachidonic acid to prostaglandins. By reducing prostaglandin production, mefenamic acid decreases inflammation, pain, and fever. This inhibition primarily occurs through the non-selective blockade of COX-1 and COX-2 isoforms.

Pharmacodynamics

The pharmacodynamics of mefenamic acid involve its analgesic, anti-inflammatory, and antipyretic properties. The drug is effective in reducing pain and inflammation due to its ability to lower prostaglandin levels, which play a key role in the inflammatory response. Mefenamic acid tends to have a rapid onset of action, typically within 1 to 2 hours after administration, and its effects can last for several hours, providing relief from pain.

Pharmacokinetics

Mefenamic acid is well absorbed from the gastrointestinal tract, with peak plasma concentrations occurring approximately 2 to 4 hours after oral administration. The drug is extensively metabolized in the liver, primarily through glucuronidation, leading to the formation of active and inactive metabolites. It has a relatively long half-life of about 2 to 4 hours, and it is excreted mainly in the urine, both as unchanged drug and as metabolites. The pharmacokinetics can be influenced by factors such as age, liver function, and concurrent medications.

Contra-indications

• Hypersensitivity to mefenamic acid or any of its excipients
• Active or history of peptic ulcer disease
• Severe heart failure
• History of gastrointestinal bleeding or perforation
• Severe hepatic impairment
• Severe renal impairment

Adverse effects

• Gastrointestinal disturbances (nausea, vomiting, diarrhea, constipation)
• Headache
• Dizziness
• Rash
• Elevated liver enzymes
• Renal impairment
• Anaphylactic reactions
• Increased risk of cardiovascular events

Interactions

• Increased exposure when used with regorafenib (severe interaction)

Precautions

• Use with caution in patients with a history of gastrointestinal disorders
• Monitor renal function in patients with compromised renal function
• Caution in patients with cardiovascular diseases
• Caution in the elderly, who may be more susceptible to adverse effects

Pregnancy

Mefenamic acid should be avoided during pregnancy, especially in the third trimester due to risks of fetal cardiovascular effects and potential complications.

Breast-feeding

Use with caution; mefenamic acid is excreted in breast milk, but significant effects on the nursing infant are not expected.

Storage

Store in a cool, dry place away from direct sunlight. Keep out of reach of children.

Formulations

• Capsules
• Tablets
• Oral suspension

Mechanism of action

Dicyclomine achieves its action partially through direct antimuscarinic activity of the M1, M3, and M2 receptors; and partially through antagonism of bradykinin and histamine. Dicyclomine non-competitively inhibits the action of bradykinin and histamine, resulting in direct action on the smooth muscle, and decreased strength of contractions seen in spasms of the ileum. ...MAJOR ACTION APPEARS TO BE NONSPECIFIC DIRECT RELAXANT ACTION ON SMOOTH MUSLCE RATHER THAN COMPETITIVE ANTAGONISM OF ACH.

Pharmacodynamics

Dicyclomine is an anticholinergic drug used to relax the smooth muscles of the intestines. It's duration of action is not especially long as it is usually taken 4 times daily with individual doses of 20-40mg orally or 10-20mg by intramuscular injection. Dicyclomine should not be administered intravenously.