The prescribing information for propranolol hydrochloride tablets lists bronchial asthma among its contraindications, and its warnings also name diabetes and hypoglycemia, allergic reactions and epinephrine, pheochromocytoma and the glaucoma screening test. Each statement is about the group or situation it names, and this guide says who. The sources used here do not say how any of these warnings apply to occasional single-dose use, and this guide does not say that they do or do not.
Asthma and breathing
The label says propranolol is contraindicated in bronchial asthma. In its Nonallergic Bronchospasm (e.g., Chronic Bronchitis, Emphysema) warning, it says that in general patients with bronchospastic lung disease should not receive beta blockers, and that propranolol should be administered with caution in this setting since it may provoke a bronchial asthmatic attack. A second set of prescribing information for propranolol hydrochloride tablets adds that it may do so by blocking bronchodilation.
A 2014 systematic review and meta-analysis of randomized controlled trials of acute beta-blocker exposure in asthma states that beta blockers are avoided in asthma over concerns regarding acute bronchoconstriction, and that risk is greatest following acute exposure, including the potential for antagonism of beta2-agonist rescue therapy. It concluded that beta-blocker-induced bronchospasm responded partially to beta2-agonists in the doses given, with response blunted more by nonselective than selective beta-blockers. That second set of prescribing information describes propranolol as a nonselective beta-adrenergic receptor blocking agent. The summary used here does not report results for propranolol alone.
A 2014 post-hoc analysis of a double blind, randomised, placebo controlled trial in mild-to-moderate asthmatics on inhaled corticosteroids reported that no bronchoconstriction was seen during up titration following the first dose of 10 mg, 20 mg or 80 mg of propranolol in the presence of tiotropium. The summary does not give the number of participants. This is a different kind of evidence from the label and the meta-analysis, and the sources do not reconcile them.
Diabetes and low blood sugar
In its Diabetes and Hypoglycemia warning, the label says beta-adrenergic blockade may prevent the appearance of certain premonitory signs and symptoms (pulse rate and pressure changes) of acute hypoglycemia, especially in labile insulin-dependent diabetics. It also says hypoglycemia has been reported in patients taking propranolol after prolonged physical exertion and in patients with renal insufficiency.
Allergy, epinephrine and pheochromocytoma
Under Hypersensitivity and Skin Reactions, the label says hypersensitivity reactions, including anaphylactic/anaphylactoid reactions, have been associated with the administration of propranolol. It also says that while taking beta blockers, patients with a history of severe anaphylactic reaction to a variety of allergens may be more reactive to repeated challenge, either accidental, diagnostic, or therapeutic, and may be unresponsive to the usual doses of epinephrine used to treat allergic reaction.
In its Pheochromocytoma warning, the label says blocking only the peripheral dilator (beta) action of epinephrine with propranolol leaves its constrictor (alpha) action unopposed.
Glaucoma test and what to tell health care professionals
The label says beta-adrenergic receptor blockade can cause reduction of intraocular pressure and that patients should be told that propranolol may interfere with the glaucoma screening test. A general FDA consumer page on managing the benefits and risks of medicines, which is not about propranolol, says in its tips for talking with your doctor, pharmacist or other health care professionals to tell them about any allergies or sensitivities that you may have. The sources used here do not list the conditions a person should mention before taking propranolol.
What this does not tell you
These are statements from the label, a general FDA consumer page and two analyses of trials. They give no numbers for how often any of these events happen. The post-hoc analysis does not show that propranolol is free of breathing effects in any person with asthma, and the label lists bronchial asthma as a contraindication. As stated at the top, the sources used here do not say how these warnings apply to occasional single-dose use. A licensed provider decides whether propranolol is appropriate for a person with any condition named here.