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
• Osteoarthritis
• Rheumatoid arthritis

Dosage

Children: Refer to the BNF for Children for specific dosing guidelines.

Adults: Refer to the BNF for specific dosing guidelines.

Mechanism of action

Mefanamic acid works by inhibiting the enzyme cyclooxygenase (COX), which is responsible for the conversion of arachidonic acid to prostaglandins. By blocking COX enzymes, mefanamic acid reduces the synthesis of prostaglandins, thereby decreasing inflammation, pain, and fever. It primarily inhibits COX-1 and COX-2, which leads to a reduction in the inflammatory response in tissues.

Pharmacodynamics

The pharmacodynamic effects of mefanamic acid include its ability to decrease pain perception and reduce inflammation. It achieves this through the inhibition of prostaglandin synthesis, which plays a crucial role in mediating pain and inflammatory processes. Mefanamic acid is particularly effective in alleviating menstrual pain due to its pronounced effect on prostaglandin levels related to uterine contractions.

Pharmacokinetics

Mefanamic acid is well absorbed from the gastrointestinal tract, with peak plasma concentrations typically occurring within 2 to 4 hours after oral administration. It has a bioavailability of approximately 90%. The drug is extensively metabolized in the liver, with a half-life ranging from 2 to 4 hours. It is primarily excreted in the urine as metabolites, with less than 1% of the dose being excreted unchanged. The pharmacokinetics can be influenced by factors such as age, liver function, and concurrent medications.

Contra-indications

• Active peptic ulceration
• History of gastrointestinal bleeding
• Severe renal impairment
• Hypersensitivity to mefanamic acid or any of its components
• Pregnancy, particularly during the third trimester

Adverse effects

• Gastrointestinal disturbances (nausea, vomiting, diarrhea)
• Dizziness
• Headache
• Rash or allergic reactions
• Increased risk of cardiovascular events with long-term use
• Hepatic dysfunction

Interactions

• May enhance the effects of anticoagulants such as warfarin
• May reduce the effect of antihypertensive drugs
• Concurrent use with other NSAIDs may increase the risk of gastrointestinal side effects
• Caution with renal excretion drugs due to potential renal impairment

Precautions

• Use with caution in patients with a history of asthma or allergic reactions
• Monitor renal function in long-term therapy
• Evaluate cardiovascular risk factors before initiation
• Avoid use in dehydration or hypovolemia

Pregnancy

Mefanamic acid is not recommended during pregnancy, especially in the third trimester due to potential effects on the fetal cardiovascular system and possible increase in bleeding risk during delivery.

Breast-feeding

Mefenamic acid is excreted in breast milk; caution is advised when administered to nursing mothers.

Storage

Store at room temperature, away from moisture and heat. 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.