Nolol 10 Tablets (Prapranolol 10mg)

Indications

• Hypertension
• Angina pectoris
• Cardiac arrhythmias
• Myocardial infarction
• Migraine prophylaxis
• Essential tremor
• Performance anxiety
• Hyperthyroidism

Dosage

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

Adults: Refer to BNF for specific dosing recommendations.

Mechanism of action

Propranolol works by blocking the action of catecholamines (such as epinephrine and norepinephrine) on beta-adrenergic receptors, particularly beta-1 and beta-2 receptors, which results in a decrease in heart rate and contractility. This action reduces the workload on the heart and lowers blood pressure. Additionally, propranolol's ability to cross the blood-brain barrier contributes to its effectiveness in treating anxiety and migraine headaches.

Pharmacodynamics

Propranolol exhibits a dose-dependent response, with higher doses producing more significant reductions in heart rate and blood pressure. Its effects on the central nervous system can also lead to anxiolytic properties, making it useful for performance anxiety. The drug can also inhibit the conversion of glycogen to glucose during stress, which may contribute to its therapeutic effects in anxiety and migraine management.

Pharmacokinetics

Propranolol is well absorbed from the gastrointestinal tract, but it undergoes significant first-pass metabolism in the liver, leading to variable bioavailability (around 25% to 35%). It is highly lipid-soluble, allowing it to cross cell membranes easily, including the blood-brain barrier. The drug is metabolized primarily by the liver via cytochrome P450 enzymes, particularly CYP2D6, and has a half-life of approximately 3 to 6 hours. Propranolol is excreted mainly in the urine as metabolites.

Contra-indications

• Asthma or severe chronic obstructive pulmonary disease
• Bradycardia
• Heart block (second or third degree)
• Cardiogenic shock
• Uncompensated heart failure
• Severe peripheral arterial disease
• Hypersensitivity to propranolol or any of its components

Adverse effects

• Fatigue
• Dizziness
• Cold extremities
• Bradycardia
• Hypotension
• Nausea
• Diarrhea
• Sleep disturbances
• Depression
• Impotence

Interactions

• Caution with other antihypertensives due to additive effects
• May enhance the effects of non-steroidal anti-inflammatory drugs (NSAIDs)
• Caution with calcium channel blockers (e.g., verapamil, diltiazem) due to increased risk of heart block
• May increase the effects of antidiabetic medications, masking hypoglycemia symptoms
• Concurrent use with monoamine oxidase inhibitors (MAOIs) may lead to increased hypotensive effects

Precautions

• Monitor blood pressure and heart rate regularly
• Use with caution in patients with diabetes or hypoglycemia
• Use with caution in patients with liver impairment
• Gradual withdrawal is recommended to avoid rebound hypertension or angina
• Caution in patients with a history of severe allergic reactions

Pregnancy

Propranolol should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. It may cause fetal bradycardia or growth retardation.

Breast-feeding

Propranolol is excreted in breast milk, and caution should be exercised when administered to nursing mothers. Monitor the infant for adverse effects.

Storage

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

Formulations

• Oral tablets
• Oral solution
• Injection