Propranolol

BRAND NAMES

Hemangeol: It contains the active ingredients of propranolol. It is available in oral solutions to treat high blood pressure and heart-related problems.

Inderal LA: It contains the active ingredients of propranolol. It is available in the form of oral extended-release capsules and tablets.

MECHANISM OF ACTION

A non-selective antagonist of β-adrenergic receptors is propranolol. Vasoconstriction, endothelial cell death, inhibition of the renin-angiotensin-aldosterone system, and inhibition of angiogenic factors like vascular endothelial growth factor and basic growth factor of fibroblasts are all brought on by blocking these receptors.

PHARMACOKINETICS

Absorption

Propranolol has a Tmax of around 2 hours, but it might range from 1 to 4 hours in fasting patients. Propranolol taken with food does not improve Tmax, but it increases bioavailability. 

Distribution

Propranolol has a volume distribution of about 4 L/kg.

Metabolism

Propranolol undergoes side chain oxidation to α-napthoxylactic acid, ring oxidation to 4-hydroxy propranolol, and glucuronidation to propranolol glucuronide. It can also be N-desisopropylated to produce N-desisopropyl propranolol, with 17% of a dosage undergoing glucuronidation and 42% undergoing ring oxidation.

Excretion

Propranolol is excreted through urine.

PHARMACODYNAMICS

Propranolol is a beta-adrenergic receptor antagonist prescribed to treat hypertension. It has a lengthy duration of action and is administered once or twice a day, depending on the indication. Patients who discontinue taking propranolol quickly may have angina flare-ups and myocardial violations. DOSAGE AND ADMINISTRATION

Propranolol is available in tablet, solution, and extended-release capsule forms for oral use. Extended-release propranolol pills are normally taken once daily. The extended-release capsule is typically given at bedtime and should be taken consistently with or without meals each time. Immediate-acting propranolol pills or solutions can be taken two, three, or four times per day.

• It is available in the form of oral solutions with the strengths of 20mg and 40mg/5ml
• It is available in tablets with strengths of 10mg, 20mg, 40mg, 60mg, and 80mg.
• It is available in extended-release tablets with the strengths of 60mg, 80mg, 120mg, and 160mg.

DRUG INTERACTIONS

•        Propranolol may interact with beta-blockers such as acebutolol, atenolol, bisoprolol, cartelol, esmolol, metoprolol, nadolol, and nebivolol, leading to a hazardous reduction in heart rate.

•        Asthma medications - theophylline 

•        Blood pressure medications include lisinopril, enalapril, diltiazem, prazosin, and terazosin. 

CONTRAINDICATIONS

Propranolol is contraindicated in cardiogenic shock, sinus bradycardia with greater than first-degree block, bronchial asthma, and congestive heart failure unless the failure is caused by a tachyarrhythmia that can be treated with propranolol.

SIDE EFFECTS

Side effects of propranolol may include

•        Tiredness

•        Constipation

•        Dizziness

•        Diarrhea

•        Some side effects of propranolol may include

•        Rash

•        Hives

•        Difficulty breathing

•        Peeling skin

•        Itching

•        Feeling faint 

•        Shortness of breath

•        Irregular heartbeat

OVERDOSE

Symptoms of overdose may include

• Fainting
• Slow heartbeat
• Dizziness
• Cough
• Fatigue

TOXICITY

When a beta-blocker overdose is suspected, patients should always be administered glucagon immediately. Glucagon has been demonstrated to be highly effective in reversing beta-blocker overdose and raising heart rate, and myocardial contractility. Ingestion of more than 1 gram of propranolol within 24 hours has the potential to be fatal, causing significant bradycardia, bradyarrhythmia, hypotension, and bronchospasm.