DIMINOR PLUS GRANULES for INJECTION 2.36g

Mechanism of action

Cyanocobalamin serves as a cofactor for methionine synthase and L-methylmalonyl-CoA mutase enzymes. Methionine synthase is essential for the synthesis of purines and pyrimidines that form DNA. L-methylmalonyl-CoA mutase is involved in the degradation of propionate, crucial for fat and protein metabolism. The lack of vitamin B12 results in the accumulation of methylmalonyl CoA, contributing to neurological manifestations. Additionally, it is vital for the synthesis of methionine from homocysteine, and its deficiency can lead to functional folate deficiency, which impacts red blood cell formation.

Pharmacodynamics

Cyanocobalamin corrects vitamin B12 deficiency and alleviates symptoms and laboratory abnormalities associated with pernicious anemia, such as megaloblastic indices, gastrointestinal lesions, and neurological damage. It is essential for growth, cell reproduction, hematopoiesis, nucleoprotein, and myelin synthesis. The drug significantly impacts fat and carbohydrate metabolism, as well as protein synthesis. Rapidly dividing cells, such as those in the bone marrow, have a high demand for vitamin B12. Parenteral administration of cyanocobalamin can quickly reverse the anemia and gastrointestinal symptoms of vitamin B12 deficiency, while also preventing the progression of related neurological damage.

Pharmacokinetics

Cyanocobalamin is absorbed in the intestine, primarily in the ileum, via specific transport mechanisms that may be impaired in individuals with intrinsic factor deficiency (as seen in pernicious anemia). Once absorbed, it is widely distributed in body tissues, with significant concentrations found in the liver, kidneys, and heart. The vitamin is stored in the liver, where it can be released into circulation as needed. Cyanocobalamin undergoes conversion to its active forms, methylcobalamin and adenosylcobalamin, which are utilized in various metabolic processes. The elimination half-life is variable, but it is generally excreted via urine as metabolites

Adverse effects

• Abdominal distension
• Decreased appetite
• Flatulence
• Nausea

Interactions

• Folic acid may interact with cyanocobalamin, especially in cases of megaloblastic anemia caused by folate deficiency.

Precautions

• Should not be given alone for pernicious anemia.
• Use caution in patients with Leber's disease, as it may worsen optic atrophy.

Pregnancy

Cyanocobalamin is essential during pregnancy as it helps prevent neural tube defects. It is advised that females of childbearing potential take 5 mg of folic acid daily before conception and throughout pregnancy.

Breast-feeding

Cyanocobalamin is generally considered safe during breastfeeding, but it is advised to monitor the infant for any adverse effects.

Storage

Store in a cool, dry place, away from direct sunlight. Protect from moisture.

Formulations

• Tablet: 1000 micrograms
• Tablet: 500 micrograms
• Tablet: 100 micrograms
• Oral solution: 50 micrograms per ml
• Solution for injection: 1000 micrograms per ml

Indications

• Muscle spasticity
• Muscle spasms
• Pain management in musculoskeletal disorders

Dosage

Children: Refer to specific pediatric guidelines or consult a healthcare professional for appropriate dosing.

Adults: Refer to specific clinical guidelines or consult a healthcare professional for appropriate dosing.

Mechanism of action

Diaceturate acts by inhibiting the presynaptic release of acetylcholine at the neuromuscular junction, thereby reducing muscle contraction. This inhibition leads to decreased excitability of motor neurons and relaxation of skeletal muscles.

Pharmacodynamics

The pharmacodynamic profile of diaceturate indicates its ability to produce muscle relaxation through central and peripheral mechanisms. It alters neurotransmitter release and modulates synaptic transmission, leading to decreased muscle tone and increased ease of movement. Its effects can be observed within a short time frame following administration, making it effective for acute muscle spasm relief.

Pharmacokinetics

Diaceturate is typically absorbed rapidly after administration, with peak plasma concentrations achieved within a few hours. It undergoes hepatic metabolism, with its metabolites being excreted primarily through the kidneys. The drug has a relatively short half-life, necessitating multiple doses for sustained effect in clinical use.

Adverse effects

• Nausea
• Vomiting
• Diarrhea
• Dizziness
• Rash

Precautions

• Use with caution in patients with liver impairment
• Monitor for allergic reactions
• Caution in patients with renal impairment

Pregnancy

The safety of diaceturate during pregnancy has not been established. It should only be used if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

Caution is advised when using diaceturate in breastfeeding women, as it's unknown if it passes into breast milk.

Storage

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

Indications

• African trypanosomiasis (sleeping sickness) caused by Trypanosoma brucei gambiense
• African trypanosomiasis (sleeping sickness) caused by Trypanosoma brucei rhodesiense

Dosage

Children: Refer to the BNF for Children for specific dosing recommendations in paediatric patients.

Adults: Refer to the BNF for specific dosing recommendations in adults.

Mechanism of action

Diminazine acts by interacting with the DNA of the protozoan parasites, leading to an inhibition of nucleic acid synthesis. It is thought to inhibit mitochondrial functions, disrupting the energy metabolism of the parasites and ultimately leading to their death. The exact molecular pathways are not fully elucidated, but it is known to interfere with the parasite's ability to replicate and survive in the host.

Pharmacodynamics

Diminazine exhibits a dose-dependent effect on the parasites, leading to a reduction in parasitemia. The drug's effectiveness is enhanced in the early stages of infection, and resistance may develop with prolonged use. The clinical response is monitored through parasitological assessments and symptom resolution, with treatment typically administered in a controlled healthcare setting.

Pharmacokinetics

Diminazine is administered parenterally and is rapidly distributed in the body. It has a moderate volume of distribution and is metabolized in the liver, with renal excretion of its metabolites. The half-life of diminazine varies, generally ranging from 4 to 10 hours, depending on individual patient factors. Therapeutic drug monitoring may be employed to assess plasma concentrations and ensure efficacy while minimizing toxicity.

Pregnancy

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

Breast-feeding

It is not known whether diminazine is excreted in human milk. Caution should be exercised when administering to a nursing mother.

Storage

Store in a cool, dry place, protected from light.

Formulations

• {'name': 'Diminazine Aceturate', 'type': 'Injection', 'strength': '100 mg/mL'}

Mechanism of action

Vitamin B12 serves as a cofactor for _methionine synthase_ and _L-methylmalonyl-CoA mutase_ enzymes. Methionine synthase is essential for the synthesis of purines and pyrimidines that form DNA. L-methylmalonyl-CoA mutase converts L-methylmalonyl-CoA to _succinyl-CoA_ in the degradation of propionate, an important reaction required for both fat and protein metabolism. It is a lack of vitamin B12 cofactor in the above reaction and the resulting accumulation of methylmalonyl CoA that is believed to be responsible for the neurological manifestations of B12 deficiency. Succinyl-CoA is also necessary for the synthesis of hemoglobin. In tissues, vitamin B12 is required for the synthesis of _methionine_ from homocysteine. Methionine is required for the formation of S-adenosylmethionine, a methyl donor for nearly 100 substrates, comprised of DNA, RNA, hormones, proteins, as well as lipids. Without vitamin B12, tetrahydrofolate cannot be regenerated from 5-methyltetrahydrofolate, and this can lead to functional folate deficiency,. This reaction is dependent on methylcobalamin (vitamin B12) as a co-factor and is also dependent on folate, in which the methyl group of methyltetrahydrofolate is transferred to homocysteine to form _methionine_ and _tetrahydrofolate_. Vitamin B12 incorporates into circulating folic acid into growing red blood cells; retaining the folate in these cells. A deficiency of vitamin B12 and the interruption of this reaction leads to the development of megaloblastic anemia.

Pharmacodynamics

**General effects** Cyanocobalamin corrects vitamin B12 deficiency and improves the symptoms and laboratory abnormalities associated with pernicious anemia (megaloblastic indices, gastrointestinal lesions, and neurologic damage). This drug aids in growth, cell reproduction, hematopoiesis, nucleoprotein, and myelin synthesis. It also plays an important role in fat metabolism, carbohydrate metabolism, as well as protein synthesis. Cells that undergo rapid division (for example, epithelial cells, bone marrow, and myeloid cells) have a high demand for vitamin B12. **Parenteral cyanocobalamin effects** The parenteral administration of vitamin B12 rapidly and completely reverses the megaloblastic anemia and gastrointestinal symptoms of vitamin B12 deficiency. Rapid parenteral administration of vitamin B12 in deficiency related neurological damage prevents the progression of this condition. **Nasal spray effects** In 24 vitamin B12 deficient patients who were already stabilized on intramuscular (IM) vitamin B12 therapy, single daily doses of intranasal cyanocobalamin for 8 weeks lead to serum vitamin B12 concentrations that were within the target therapeutic range (>200 ng/L).