Propranolol (inderal) is used extensively as treatment for what condition?

Propranolol

Inderal, Inderal LA, Hemangeol, and generics

Adrenergic blocking agent (β), class II antiarrhythmic

Tabs: 10, 20, 40, 60, 80 mg

Extended-release caps (Inderal LA and others including generics): 60, 80, 120, 160 mg

Oral solution: 20 mg/5 mL, 40 mg/5 mL; contains parabens and saccharin

Hemangeol: 4.28 mg/mL (120 mL); alcohol, sugar and parabens free; contains saccharin

Injection: 1 mg/mL (1 mL)

Arrhythmias:

Child:

IV: 0.01–0.1 mg/kg/dose IV push over 10 min, repeat Q6–8 hr PRN;max. dose: 1 mg/dose for infant; 3 mg/dose for child

PO: Start at 0.5–1 mg/kg/24 hr ÷ Q6–8 hr; increase dosage Q3–5 days PRN. Usual dosage range: 2–4 mg/kg/24 hr ÷ Q6–8 hr;max. dose: 60 mg/24 hr or 16 mg/kg/24 hr

Adult:

IV: 1 mg/dose Q5 min up to total 5 mg

PO: 10–30 mg/dose TID–QID; increase PRN. Usual range 30–160 mg/24 hr ÷ TID–QID.

Hypertension (as alternative therapy):

Child:

PO: Initial: 0.5–1 mg/kg/24 hr ÷ Q6–12 hr. May increase dose Q5–7 days PRN;max. dose: 8 mg/kg/24 hr

Adult:

PO: 40 mg/dose PO BID or 60–80 mg/dose (sustained-release capsule) PO once daily. May increase 10–20 mg/dose Q3–7 days;max. dose: 640 mg/24 hr.

Migraine prophylaxis:

Child:

<35 kg: Start with 10 mg PO once daily and increase dose PRN weekly intervals at 10 mg increments. Usual dosage range: 10–20 mg PO TID.

≥35 kg: 20–40 mg PO TID

Adult: 80 mg/24 hr ÷ Q6–8 hr PO; increase dose by 20–40 mg/dose Q3–4 wk PRN. Usual effective dose range: 160–240 mg/24 hr.

Tetralogy spells:

IV: 0.15–0.25 mg/kg/dose slow IV push. May repeat in 15 min ×1. See alsoChapter 7.

PO: Start at 2–4 mg/kg/24 hr ÷ Q6 hr PRN. Usual dose range: 4–8 mg/kg/24 hr ÷ Q6 hr PRN. Doses as high as 15 mg/kg/24 hr have been used with careful monitoring.

Thyrotoxicosis:

Neonate: 2 mg/kg/24 hr PO ÷ Q6–12 hr

Adolescent and adult:

IV: 1–3 mg/dose over 10 min. May repeat in 4–6 hr.

PO: 10–40 mg/dose PO Q6 hr

Infantile hemangioma (see remarks):

Infant (5 wk–5 mo and ≥2 kg; labeled dosing information for Hemangeol product): 0.6 mg/kg/dose BID PO (at least 9 hr apart) ×7 days, then increase to 1.1 mg/kg/dose BID PO ×14 days, followed by 1.7 mg/kg/dose BID PO ×6 mo.

Alternative dosing: Start at 1 mg/kg/24 hr ÷ Q8 hr PO. If tolerated after 1 day, increase dose to 2 mg/kg/24 hr ÷ Q8 hr PO

Thyrotoxicosis Due to Metastatic Thyroid Carcinoma

In general, thyroid carcinomas are made up of poorly functioning tissue. On occasion, follicular thyroid carcinomas will have sufficient function when combined with the total mass of the metastases to result in an elevation in serum free T4 or T3 and may even be seen in Graves disease with TRAbs activating the tissue.383 Typically such a course is a complication of a previously diagnosed lesion.384 The symptoms of thyrotoxicosis will vary and the metastatic disease is usually obvious from radiologic studies. On occasion, the presentation may be confusing if the patient is receiving TSH-suppressive therapy, and diagnosis will require its discontinuation. In spite of that, TSH will remain suppressed and the serum free T4 is elevated. Treatment of this condition is typical for that of thyroid carcinoma and is described inChapter 14. In patients with thyrotoxicosis due to metastatic tumor, serum Tg is quite elevated, indicating that the thyrotoxicosis is caused by thyroidal tissue that is not located in the neck. An RAIU during the thyrotoxic phase will show no neck uptake due to TSH suppression even if the thyroid is still present.

6.1.2 Distribution

Propranolol is widely distributed into body tissues including lungs, liver, kidneys, and heart. Propranolol readily crosses the blood–brain barrier and the placenta. The drug is distributed into milk.

The apparent volume of distribution of propranolol at steady state varies widely in proportion to the fraction of unbound drug in whole blood. Propranolol is more than 90% bound to plasma proteins over a wide range of blood concentrations. Both free and protein-bound propranolol are metabolized. Increased plasma protein binding of the drug increases its metabolism and decreases its volume of distribution, resulting in a shorter terminal half-life [29].

Propranolol

Propranolol (Inderal, Ipran), the prototypical β-blocker, is a nonselective β-blocking drug. Because of its high lipid solubility, it is extensively metabolized in the liver, but metabolism varies greatly from patient to patient. Clearance of the drug can be affected by liver disease or altered hepatic blood flow. Propranolol is available in an intravenous form and was initially given as either a bolus or an infusion. Infusions of propranolol have largely been supplanted by the shorter-acting esmolol. For bolus administration, doses of 0.1 mg/kg may be given, but most practitioners initiate therapy with much smaller doses, typically 0.25 to 0.5 mg, and titrate to effect. Propranolol shifts the oxyhemoglobin dissociation curve to the right, which might account for its efficacy in vasospastic disorders.15 Additionally, propranolol is commonly used in the treatment of hyperthyroidism to mitigate tachycardia that may result.

Organs and systems

Propranolol

Propranolol is 1-(iso-propylamino)-3-(1-naphthoxy)-2-propanol (12.1.2). The synthesis of this drug is described in Chapter 12.

Propranolol is a nonselective β-adrenoblocker that affects both the mechanical and electrophysiological properties of the myocardium. It lowers myocardial contractibility, heart rate, blood pressure, and the myocardial need for oxygen. These properties make propranolol and other β-adrenoblockers useful antianginal drugs.

Propranolol is used for treating hypertension, angina pectoris, supraventricular arrhythmia, ventricular tachycardia, migraines, hypertrophic subaortal stenosis, and pheochromocytosis. It is used following a myocardial infraction. Generally accepted synonyms of this drug are anaprilin, obsidan, inderal, novapranol, and defensol.

PROPRANOLOL

Propranolol (Inderal, Wyeth-Ayerst Laboratory, Philadelphia) is a non-selective β-adrenergic antagonist that is used widely for the treatment of a diverse group of medical conditions including arrhythmia, angina, hypertension, and migraine. Propranolol lowers IOP when administered topically,144,145 orally,146,147 or intravenously.148 The drug has been shown to reduce aqueous humor formation in both monkey and human eyes.149,150 Most physicians have abandoned propranolol as a treatment for glaucoma because its membrane-stabilizing properties produce corneal anesthesia. Patients who are treated with oral propranolol for a medical condition such as hypertension generally experience a decrease in IOP, particularly when the dose exceeds 10 mg/day.151,152

Clinical applications

Propranolol is indicated in canine and feline patients with ventricular and supraventricular tachyarrhythmias. It is commonly used with digoxin to slow the ventricular rate in patients with atrial fibrillation. It is effective for terminating and preventing the recurrence of supraventricular tachycardia.

Propranolol can be effective as the sole agent for terminating ventricular tachyarrhythmias but is generally more effective when used in combination with other antiarrhythmic agents. Propranolol is effective for decreasing the sinus rate in patients with hyperthyroidism, pheochromocytoma and heart failure. Few antiarrhythmic drugs can be used in cats. Propranolol has been used to treat both supraventricular and ventricular tachyarrhythmias in cats with moderate success.