WINTERGREEN 25% OINTMENT

Indications

• Attention Deficit Hyperactivity Disorder (ADHD)
• Narcolepsy

Dosage

Children: Refer to the BNF for Children for precise dosing recommendations tailored to the pediatric population.

Adults: Refer to the BNF for specific dosing guidelines, as doses may vary based on individual patient needs and the formulation used.

Mechanism of action

Methylphenidate primarily acts as a dopamine reuptake inhibitor, blocking the reuptake of dopamine and norepinephrine into neurons. This results in increased synaptic concentrations of these neurotransmitters in the central nervous system, leading to enhanced neurotransmission and improved attention and focus.

Pharmacodynamics

The pharmacodynamic effects of methylphenidate are characterized by its ability to increase attention, decrease impulsiveness, and reduce hyperactivity in patients with ADHD. Its effects are dose-dependent, and it has a relatively quick onset of action, with peak effects typically observed within 1 to 2 hours after oral administration. The duration of action can vary based on the formulation (immediate-release vs extended-release).

Pharmacokinetics

Methylphenidate is well-absorbed from the gastrointestinal tract, with peak plasma concentrations occurring approximately 1 to 2 hours after oral dosing. It has a half-life of about 2 to 3 hours for the immediate-release formulation, whereas extended-release formulations can have a longer duration of action. It is metabolized in the liver primarily via ester hydrolysis and is excreted mainly in the urine as metabolites. Food can affect its absorption, and it should be taken consistently with or without food to maintain steady plasma levels.

Adverse effects

• Nausea
• Vomiting
• Headache
• Insomnia
• Anxiety
• Increased heart rate
• Hypertension

Interactions

• May interact with other central nervous system stimulants
• Potential interactions with monoamine oxidase inhibitors (MAOIs)
• May reduce the effectiveness of antihypertensive medications

Precautions

• Use with caution in patients with a history of cardiovascular disease
• Monitor blood pressure and heart rate regularly
• Use in children should be under strict medical supervision

Pregnancy

Use during pregnancy only if the potential benefit justifies the potential risk to the fetus. Consult healthcare providers.

Breast-feeding

Use with caution while breastfeeding. Potential effects on the infant should be considered.

Storage

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

Indications

• Pain relief
• Fever reduction
• Inflammatory conditions such as arthritis
• Prevention of cardiovascular events in certain populations

Dosage

Children: Refer to the BNF for Children for specific dosing guidelines.

Adults: Refer to the BNF for specific dosing guidelines.

Mechanism of action

Salicylate works by inhibiting the enzyme cyclooxygenase (COX), which is involved in the synthesis of prostaglandins. Prostaglandins are lipid compounds that mediate inflammation, pain, and fever. By decreasing the production of these compounds, salicylate effectively reduces inflammation and provides analgesic and antipyretic effects.

Pharmacodynamics

The pharmacodynamic effects of salicylate include analgesia, antipyresis, and anti-inflammatory action. It reduces the sensitivity of pain receptors and inhibits the generation of pain signals. The antipyretic effect is achieved through action on the hypothalamus, leading to peripheral vasodilation and sweating, thereby reducing body temperature. The drug also modulates the immune response, contributing to its anti-inflammatory properties.

Pharmacokinetics

Salicylate is rapidly absorbed from the gastrointestinal tract following oral administration. Peak plasma concentrations are typically reached within 1 to 2 hours. It is extensively metabolized in the liver, primarily through conjugation, and its metabolites are excreted in the urine. The elimination half-life of salicylate varies depending on the dose and the presence of other medications, averaging around 2 to 3 hours at low doses, but can be prolonged at higher doses due to saturation of metabolic pathways.

Contra-indications

• Hypersensitivity to salicylates
• Active peptic ulcer disease
• Severe hepatic impairment
• Severe renal impairment
• Bleeding disorders
• Children with viral infections (due to risk of Reye's syndrome)

Adverse effects

• Gastrointestinal irritation
• Nausea
• Vomiting
• Tinnitus
• Hearing loss
• Allergic reactions
• Rash
• Asthma exacerbation
• Gastric ulceration

Interactions

• Anticoagulants (increased bleeding risk)
• Methotrexate (increased toxicity)
• NSAIDs (increased gastrointestinal side effects)
• Diuretics (reduced efficacy)
• Alcohol (increased risk of gastrointestinal bleeding)

Precautions

• Use with caution in patients with a history of gastrointestinal disease
• Monitor renal function in long-term use
• Caution in patients with asthma or allergies
• Consider alternative therapy in children with viral infections

Pregnancy

Use with caution during pregnancy, particularly in the third trimester, as it may affect fetal development.

Breast-feeding

Salicylate is excreted in breast milk; caution is advised when administering to breastfeeding mothers.

Storage

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

Formulations

• Tablets
• Oral suspension
• Topical preparations
• Suppositories