QUINALIN 100MG/5ML SYRUP

Indications

• Preservative in pharmaceutical formulations
• Antioxidant in food and drug products
• Stabilizer for certain active pharmaceutical ingredients

Dosage

Children: Refer to specific formulation guidelines and BNF for Children for appropriate dosing.

Adults: Refer to specific formulation guidelines and BNF for appropriate dosing.

Mechanism of action

Bisulfate acts as a reducing agent by donating electrons to other molecules. This electron donation helps to neutralize free radicals and prevent oxidative damage. In the context of pharmacology, bisulfate can also interact with sulfhydryl groups in proteins, influencing their structure and function.

Pharmacodynamics

The pharmacodynamic properties of bisulfate are related to its ability to act as a reducing agent and antioxidant. It can protect cells from oxidative stress, which is linked to various pathological conditions. Its role in stabilizing drug formulations also impacts the pharmacodynamic profile of the therapeutic agents it is combined with, ensuring their efficacy and safety.

Pharmacokinetics

The pharmacokinetics of bisulfate, when used in medicinal formulations, involves its absorption, distribution, metabolism, and excretion. Generally, bisulfate is well absorbed in the gastrointestinal tract when ingested. It is rapidly distributed throughout the body and can be metabolized to sulfate. Excretion primarily occurs through the kidneys, with a significant portion being eliminated in urine.

Contra-indications

• Hypersensitivity to bisulfate or any of its components
• Severe asthma or respiratory conditions
• History of allergic reactions to sulfites

Adverse effects

• Hypersensitivity reactions including anaphylaxis
• Bronchospasm
• Respiratory distress
• Skin reactions such as rash or urticaria
• Itching
• Headache
• Nausea

Interactions

• May interact with other medications that induce or inhibit sulfite metabolism
• Caution is advised when used with other drugs that can cause bronchospasm
• Potential for increased sensitivity when combined with certain anesthetics and analgesics

Precautions

• Use with caution in patients with asthma or history of sulfite sensitivity
• Monitor for signs of allergic reactions in sensitive individuals
• Consider alternative therapies in patients known to have sulfite allergies

Pregnancy

Safety during pregnancy has not been established. Use only if clearly needed.

Breast-feeding

Use with caution while breastfeeding. Monitor for any adverse effects in the infant.

Storage

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

Formulations

• Oral tablets
• Injectable solution

Indications

• Treatment of uncomplicated malaria caused by Plasmodium falciparum
• Treatment of severe malaria
• Management of nocturnal leg cramps

Dosage

Children: Refer to the BNF for Children for specific dosing information based on age and weight.

Adults: Refer to local guidelines for specific dosing information, including adjustments for renal function.

Mechanism of action

Quinine acts by interfering with the parasite's ability to digest hemoglobin. It inhibits the polymerization of heme, which is toxic to the Plasmodium species, leading to the accumulation of free heme and ultimately the death of the parasite. Quinine also exhibits some activity against the gametocytes of Plasmodium falciparum, reducing transmission.

Pharmacodynamics

Quinine is a cinchona alkaloid that exhibits a concentration-dependent effect on the malaria parasite. It has a significant effect on the asexual blood stages of the parasite and is effective in both uncomplicated and severe malaria, particularly caused by Plasmodium falciparum. Quinine can also have mild analgesic properties and may influence muscle contraction.

Pharmacokinetics

Quinine is well absorbed from the gastrointestinal tract, with peak plasma concentrations occurring within 1-3 hours after oral administration. It is extensively metabolized in the liver, primarily via CYP3A4 and CYP2D6 pathways, and has a half-life ranging from 10 to 12 hours. Renal excretion is the primary route of elimination for its metabolites, which necessitates dose adjustments in patients with renal impairment.

Contra-indications

• Hypersensitivity to quinine or any of its components
• Myasthenia gravis
• Torsades de pointes or other forms of ventricular tachycardia
• Severe thrombocytopenia
• G6PD deficiency

Adverse effects

• Cinchonism (tinnitus, headache, nausea, visual disturbances)
• Hypotension
• Hypersensitivity reactions (urticaria, angioedema)
• Hemolytic anemia
• Thrombocytopenia
• Cardiac arrhythmias
• Gastrointestinal disturbances (nausea, vomiting, diarrhea)

Interactions

• Increased risk of bleeding with anticoagulants (e.g., warfarin)
• Increased plasma concentrations of digoxin
• Coadministration with other QT interval prolonging drugs may increase the risk of arrhythmias
• May interact with antimalarial drugs, increasing toxicity

Precautions

• Monitor cardiac function in patients with pre-existing heart conditions
• Use with caution in patients with renal impairment
• Regular monitoring of platelet counts in patients with a history of thrombocytopenia
• Assess for signs of cinchonism, especially in prolonged therapy

Pregnancy

Quinine is classified as Category C. It should only be used if the potential benefit justifies the potential risk to the fetus. It is contraindicated in the first trimester.

Breast-feeding

Quinine is excreted in breast milk. Caution is advised when used in breastfeeding women, and alternatives may be considered.

Storage

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

Formulations

• Oral tablets (various strengths)
• Injectable solution