Isorem 10

Indications

• Pediatric dosing adjustments
• Intravenous therapy
• Intramuscular injections
• Topical applications
• Oral medications for easier swallowing

Dosage

Children: Refer to the BNF for Children for appropriate dosing adjustments based on age and weight.

Adults: Refer to specific drug guidelines for appropriate dilution and dosage based on the active ingredient.

Mechanism of action

The mechanism of action of a diluted drug depends on the specific active ingredient within the solution. Generally, when a drug is diluted, its pharmacological effects are proportional to its concentration. The active molecules interact with specific receptors or enzymes in the body, leading to a desired therapeutic effect. For example, an analgesic diluted for oral administration will still bind to pain receptors, albeit at a lower intensity compared to its concentrated form.

Pharmacodynamics

Pharmacodynamics refers to the relationship between drug concentration and its effect on the body. In diluted solutions, the pharmacodynamic properties of the active ingredient remain intact, though the therapeutic effect may be reduced due to the lower concentration. The efficacy of the drug is influenced by factors such as receptor affinity, intrinsic activity, and the presence of other substances in the formulation.

Pharmacokinetics

Pharmacokinetics involves the absorption, distribution, metabolism, and excretion (ADME) of drugs. For diluted drugs, absorption can be affected by the dilution medium, which may enhance or delay the onset of action. Distribution is generally influenced by the volume of distribution of the active ingredient. Metabolism occurs primarily in the liver, where the drug is biotransformed, and excretion is typically via the kidneys. The pharmacokinetic profile may differ based on the dilution level and formulation.

Pregnancy

Consult a healthcare provider, as the effects of diluted preparations can vary depending on the active ingredient.

Breast-feeding

Consult a healthcare provider, as the safety of diluted preparations during breastfeeding can depend on the active ingredient.

Storage

Store in a cool, dry place away from direct sunlight. Ensure that the specific active ingredient's storage requirements are followed.

Indications

• Angina pectoris
• Heart failure
• Acute coronary syndrome
• Hypertensive emergencies

Dosage

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

Adults: Refer to the BNF for specific dosage guidelines.

Mechanism of action

Isosorbide dinitrate is converted in the body to nitric oxide, which activates guanylate cyclase, leading to increased levels of cyclic GMP. This results in relaxation of smooth muscle in the vascular wall, causing vasodilation. The primary effects include reduced preload and afterload on the heart, leading to decreased myocardial oxygen demand.

Pharmacodynamics

The pharmacodynamic effects of isosorbide dinitrate include vasodilation, which reduces cardiac workload and improves oxygen supply to the heart muscle. The onset of action is typically within 20 to 30 minutes when administered orally, with peak effects occurring around 1 to 2 hours. The duration of action can last several hours, depending on the formulation.

Pharmacokinetics

Isosorbide dinitrate is rapidly absorbed from the gastrointestinal tract, with bioavailability ranging from 20% to 30% due to first-pass metabolism. Peak plasma concentrations are reached approximately 1 hour after oral administration. The drug is metabolized in the liver to active and inactive metabolites, with a half-life of 1 to 4 hours. It is primarily excreted through the kidneys as metabolites.

Contra-indications

• Hypersensitivity to dinitrates or any of their components
• Severe anemia
• Closed-angle glaucoma
• Cardiogenic shock
• Severe hypotension
• Concurrent use with phosphodiesterase type 5 inhibitors (e.g., sildenafil)

Adverse effects

• Headache
• Dizziness
• Flushing
• Hypotension
• Tachycardia
• Nausea
• Palpitations

Interactions

• May enhance the hypotensive effects of antihypertensive agents
• Concurrent use with other nitrates can lead to additive effects
• Increased risk of hypotension when used with alcohol
• May interact with drugs that affect hepatic metabolism

Precautions

• Use with caution in patients with hepatic or renal impairment
• Monitor blood pressure regularly
• Taper doses gradually to prevent withdrawal symptoms
• Consider potential for tolerance with long-term use

Pregnancy

There are no adequate and well-controlled studies in pregnant women. Use only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

Dinitrate is excreted in breast milk. Caution should be exercised when administered to a nursing mother.

Storage

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

Formulations

• Sublingual tablets
• Oral tablets
• Topical ointments
• Transdermal patches

Indications

• Angina pectoris
• Heart failure
• Hypertension
• Intraocular pressure management

Dosage

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

Adults: Refer to BNF for specific dosing recommendations based on individual patient needs and clinical indications.

Mechanism of action

Isosorbide causes vascular relaxation, reducing systolic ophthalmic artery pressure (SOAP) and systolic ocular perfusion pressure (SOPP). This mechanism contributes to its effectiveness in treating conditions characterized by elevated intraocular pressure.

Pharmacodynamics

Isosorbide reduces intraocular pressure through its effects on ocular blood vessels. While in the blood, isosorbide promotes the redistribution of water toward the circulation, which enhances urinary excretion. This diuretic effect can help alleviate symptoms related to fluid overload in certain cardiovascular conditions.

Pharmacokinetics

Isosorbide is absorbed well from the gastrointestinal tract with peak plasma concentrations occurring within 1 to 2 hours after oral administration. It undergoes extensive first-pass metabolism, which significantly reduces its bioavailability. The drug is primarily eliminated through the kidneys, with a half-life ranging from 5 to 6 hours, but this may vary based on formulation and patient factors.

Mechanism of action

Isosorbide causes vascular relaxation, reducing systolic ophthalmic artery pressure (SOAP), systolic ocular perfusion pressure (SOPP).

Pharmacodynamics

Isosorbide reduces intraocular pressure through its effects on ocular blood vessels. While in the blood, isosorbide promotes redistribution of water toward the circulation, promoting the excretion of urine.