Pause MF Tablets

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

Indications

• Heavy menstrual bleeding (menorrhagia)
• Surgical procedures to reduce blood loss
• Trauma-related bleeding
• Hereditary angioedema
• Dental procedures in patients with bleeding disorders

Dosage

Children: Refer to the BNF for Children for specific dosing guidelines based on age, weight, and indication.

Adults: Refer to the BNF for specific dosing guidelines based on indication and patient condition.

Mechanism of action

Tranexamic acid competitively inhibits the lysine binding sites on plasminogen, preventing its conversion to plasmin. This inhibition decreases fibrinolysis, leading to increased clot stability and reduced bleeding.

Pharmacodynamics

The primary pharmacodynamic effect of tranexamic acid is its ability to reduce bleeding by stabilizing fibrin clots. The drug exhibits a dose-dependent effect on clotting, with higher doses leading to a more pronounced antifibrinolytic effect. Tranexamic acid does not significantly affect platelet function or coagulation factors.

Pharmacokinetics

Tranexamic acid is rapidly absorbed after oral administration, with peak plasma concentrations occurring within 1 to 3 hours. It has a bioavailability of approximately 30% to 50%. The drug is primarily excreted unchanged in the urine, with a half-life of approximately 2 hours. It does not undergo significant metabolism in the liver, which is beneficial in patients with hepatic impairment.

Contra-indications

• Active venous thromboembolism
• History of thromboembolic disorders
• Severe renal impairment
• Hypersensitivity to tranexamic acid or any excipients

Adverse effects

• Nausea
• Vomiting
• Diarrhea
• Abdominal pain
• Dizziness
• Headache
• Visual disturbances
• Thrombosis
• Hypotension
• Allergic reactions

Interactions

• Anticoagulants (increased risk of thrombosis)
• Hormonal contraceptives (increased risk of thrombosis)
• Fibrinolytics (increased risk of bleeding)

Precautions

• Monitor for signs of thrombosis during treatment
• Use with caution in patients with a history of seizures
• Caution in patients with renal impairment
• Assess the risk of bleeding before use

Pregnancy

Tranexamic acid should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

Tranexamic acid is excreted in breast milk; caution should be exercised when administered to nursing mothers.

Storage

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

Formulations

• Tablets
• Injection solution