STREPSILS ORANGE WITH VITAMIN C LOZENGES

Indications

• Angina pectoris
• Diagnostic procedures in medicine
• Recreational use for psychoactive effects

Dosage

Children: Refer to established clinical guidelines or specific product information for dosing recommendations.

Adults: Refer to established clinical guidelines or specific product information for dosing recommendations.

Mechanism of action

Amyl nitrite acts by releasing nitric oxide (NO) in the body, which leads to the relaxation of smooth muscle and vasodilation. This effect is primarily mediated through the activation of guanylate cyclase, leading to increased levels of cyclic guanosine monophosphate (cGMP) in vascular smooth muscle cells, resulting in decreased vascular resistance and increased blood flow, especially to the coronary arteries.

Pharmacodynamics

The pharmacodynamic effects of amyl nitrite include the relaxation of vascular smooth muscle, leading to decreased preload and afterload on the heart, which can result in a reduction of myocardial oxygen demand. The onset of action is rapid, typically within minutes, and effects can last for a short duration, making it suitable for acute relief of anginal symptoms. The drug can also cause hypotension, tachycardia, and headache due to its vasodilatory effects.

Pharmacokinetics

Amyl nitrite is rapidly absorbed after inhalation or sublingual administration. It has a very short half-life, usually around 3 to 5 minutes, leading to quick onset of action. The metabolism occurs primarily in the liver via conjugation with glucuronic acid, and the excretion is predominantly via urine. The rapid clearance of the drug necessitates frequent dosing for sustained effects, particularly in the management of angina.

Contra-indications

• Hypersensitivity to amyl nitrite or any of its components
• Severe anemia
• Increased intracranial pressure
• Hypotension
• Severe heart failure

Adverse effects

• Headache
• Dizziness
• Flushing
• Tachycardia
• Hypotension
• Nausea
• Vomiting
• Methemoglobinemia

Interactions

• Concurrent use with phosphodiesterase type 5 inhibitors (e.g., sildenafil) can lead to profound hypotension
• Use with other antihypertensive agents may enhance hypotensive effects
• Alcohol may exacerbate vasodilatory effects

Precautions

• Use with caution in patients with pre-existing cardiovascular conditions
• Monitor blood pressure regularly during treatment
• Caution in patients with a history of substance abuse
• Avoid use in patients with severe liver or kidney impairment

Pregnancy

Amyl nitrite is classified as category C. 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

It is not known whether amyl nitrite is excreted in human milk. Caution is advised when administering to nursing mothers.

Storage

Store in a tightly closed container at room temperature, away from light and moisture. Keep out of reach of children.

Formulations

• Amyl nitrite inhalation solution

Indications

• Disinfection of skin and mucous membranes
• Preservative in pharmaceutical formulations
• Antiseptic in medical and veterinary applications

Dosage

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

Adults: Refer to BNF for specific dosing guidelines based on the formulation and condition being treated.

Mechanism of action

Metacresol exhibits antimicrobial activity by disrupting the cell membrane of bacteria, leading to cell lysis and death. Its effectiveness is attributed to its ability to denature proteins and dissolve lipid membranes, which is critical for maintaining the integrity of bacterial cells.

Pharmacodynamics

The pharmacodynamic effects of metacresol are primarily related to its antiseptic and disinfectant properties. It is effective against a wide range of pathogens, including bacteria, fungi, and some viruses. The concentration and exposure time are key factors that influence its efficacy, with higher concentrations generally leading to increased antimicrobial activity.

Pharmacokinetics

Metacresol is absorbed through the skin and mucous membranes, and its systemic absorption can vary based on the route of administration. It is metabolized primarily in the liver and excreted in the urine. The half-life and excretion rates can vary significantly based on individual factors such as age and liver function. Precautions should be taken to minimize exposure due to its potential toxicity.

Pregnancy

There is limited data on the use of metacresol in pregnancy. It is advisable to avoid use unless the potential benefits outweigh the risks.

Breast-feeding

Caution is advised when using metacresol during breastfeeding, as the effects on the nursing infant are not well studied.

Storage

Store in a tightly sealed container at room temperature, away from light and moisture.