Bisoprolol

Mechanism

Both drugs slow the heart rate and cardiac conduction. Bisoprolol is a selective beta-blocker (bisoprolol SmPC). Amiodarone blocks alpha and beta adrenoceptors non-competitively and slows conduction through the sinus and atrioventricular nodes (amiodarone SmPC). Together they increase bradycardia and conduction disorders (both SmPCs). Amiodarone is eliminated over months, so the interaction can persist for several months after it is stopped (amiodarone SmPC).

Symptoms

Marked bradycardia, dizziness, weakness, fainting. On the ECG: atrioventricular block of varying degree, sinoatrial block, and rarely sinus arrest. In older patients the heart rate can fall especially sharply (amiodarone SmPC).

Management

The amiodarone SmPC does not recommend combining it with beta-blockers because of the risk of marked bradycardia and conduction disorders. The bisoprolol SmPC lists the combination with amiodarone as one to use with caution. If a cardiologist still prescribes both, monitor the heart rate (US Food and Drug Administration (FDA) amiodarone label). Before amiodarone is started, record an ECG and check serum potassium (amiodarone SmPC). Stop amiodarone if second- or third-degree atrioventricular block, sinoatrial block or bifascicular block develops (amiodarone SmPC). In older patients the heart rate can fall especially sharply. The interaction can persist for several months after amiodarone is stopped, so keep checking the heart rate after that too (amiodarone SmPC).

Mechanism

Abrupt clonidine withdrawal on a beta-blocker triggers a hypertensive crisis: the α2 effect is lost while β-blockade persists – an 'unopposed' α1 effect develops with a sharp blood pressure rise.

Symptoms

Abrupt clonidine withdrawal causes hypertensive crisis: sharp blood pressure rise, headache, tachycardia, anxiety, sweating. Symptoms appear 18–24 hours after a missed clonidine dose.

Management

For planned clonidine withdrawal, stop bisoprolol 3–7 days beforehand, then taper clonidine over 1–2 weeks. Alternative antihypertensives: an ACE-I (enalapril) plus amlodipine without clonidine.

Mechanism

Non-dihydropyridine calcium channel blocker (diltiazem) + beta-blocker (bisoprolol) – additive AV node blockade and negative inotropic effect.

Symptoms

Bradycardia (heart rate below 50/min), dizziness, syncope. ECG: first- to second-degree AV block. Older patients: fall risk.

Management

Avoid the combination. For atrial fibrillation rate control, choose bisoprolol + digoxin (without diltiazem) or diltiazem with bisoprolol withdrawn.

Mechanism

Dronedarone has properties of all four Vaughan-Williams antiarrhythmic classes, including antiadrenergic activity (dronedarone SmPC). In healthy volunteers it lengthened the PR interval, meaning slower conduction from the atria to the ventricles, by about 12 ms at 400 mg twice daily (dronedarone label of the US Food and Drug Administration, FDA). Bisoprolol, as a beta-blocker, also slows the heart rate and conduction. In clinical studies bradycardia was seen more often when dronedarone was combined with beta-blockers (dronedarone SmPC).

Symptoms

Slow pulse, weakness, dizziness, fainting. On the electrocardiogram (ECG): bradycardia, PR prolongation, atrioventricular block.

Management

The dronedarone SmPC says beta-blockers should be used with caution with dronedarone: start at a low dose and increase it only after an electrocardiogram (ECG) check. In patients already on a beta-blocker, record an ECG when dronedarone is started and adjust the beta-blocker dose if needed (dronedarone SmPC). The US Food and Drug Administration (FDA) gives the same rule: a low starting dose of the beta-blocker, increased only after the ECG confirms good tolerability (dronedarone FDA label). Dronedarone is contraindicated with a heart rate below 50 beats per minute and with second- or third-degree atrioventricular block without a pacemaker (dronedarone SmPC); bisoprolol is contraindicated with second- or third-degree atrioventricular block without a pacemaker and with symptomatic bradycardia (bisoprolol SmPC). During dronedarone treatment, record an ECG regularly, at least every 6 months (dronedarone SmPC).

Mechanism

Additive AV slowing and reduced contractility. Bradycardia, AV block.

Symptoms

Bradycardia, AV block.

Management

Avoid combination.

Mechanism

Additive bradycardia and hypotension. Alprazolam sedation may mask early symptoms of excessive blood pressure drop.

Symptoms

Lower blood pressure, postural dizziness, fatigue. Older patients: fall risk. With additional antihypertensives: bradycardia (pulse below 60/min).

Management

The combination is acceptable for short alprazolam use with pulse and blood pressure monitoring. In older patients, lorazepam at minimum doses is preferable with fall risk warning.

Mechanism

Amitriptyline (TCA) causes orthostatic hypotension via α1-adrenergic blockade. Combined with bisoprolol: dizziness on standing. Anticholinergic effect of amitriptyline may aggravate bradycardia.

Symptoms

Lower blood pressure, postural dizziness, fatigue. Older patients: fall risk. With additional antihypertensives: bradycardia (pulse below 60/min).

Management

The combination is acceptable at low amitriptyline doses (25–50 mg). For neuropathic pain, gabapentin or pregabalin (no α1-blockade) is preferable. Check blood pressure standing and sitting at 1 week after start.

Mechanism

Dihydropyridine calcium channel blocker (amlodipine) + cardioselective beta-blocker (bisoprolol) – additive bradycardia and hypotension. In reduced ejection fraction (below 40%), heart failure decompensation risk.

Symptoms

Lower blood pressure, postural dizziness, fatigue. Older patients: fall risk. With additional antihypertensives: bradycardia (pulse below 60/min).

Management

The combination is a standard hypertension and angina treatment. In heart failure with reduced ejection fraction, cap amlodipine at 5 mg/day. Check pulse and blood pressure at 1–2 weeks.

Mechanism

Systemic (oral) budesonide causes sodium retention and weakens the antihypertensive effect of the beta-blocker. With inhaled use, systemic effect is minimal, so no clinical impact.

Symptoms

Gradual blood pressure rise 2–4 weeks after starting the glucocorticoid. In heart failure: oedema, weight gain.

Management

Inhaled budesonide for asthma or COPD does not require bisoprolol adjustment. For oral therapy in inflammatory bowel disease, check blood pressure every 2–4 weeks.

Mechanism

Bupropion blocks CYP2D6. Bisoprolol is metabolised 50% via CYP3A4 and 50% renally, so the effect is clinically minor, unlike metoprolol (fully CYP2D6).

Symptoms

Minimal changes: mild additional bradycardia possible. Older patients: rare symptomatic hypotension.

Management

Dose adjustment is usually unnecessary. In older patients and reduced ejection fraction, check pulse and blood pressure 2 weeks after start.

Mechanism

Calcium carbonate may reduce bisoprolol GI absorption when taken simultaneously. The effect is weak and clinically minor.

Symptoms

Minimal changes. In some patients, mild return of hypertension or angina symptoms with prolonged concurrent use.

Management

Separate bisoprolol and calcium carbonate by 2 hours. Most patients require no special adjustment.

Mechanism

Dexamethasone causes sodium and water retention via mineralocorticoid effect, reducing the antihypertensive effect of the beta-blocker.

Symptoms

Gradual blood pressure rise 2–4 weeks after starting the glucocorticoid. In heart failure: oedema, weight gain.

Management

For short dexamethasone courses (up to 7 days), no adjustment. For prolonged systemic therapy, increase bisoprolol or add a diuretic (hydrochlorothiazide, indapamide) with blood pressure monitoring.

Mechanism

Additive CNS depression and mild hypotension. Diazepam sedation may mask early symptoms of excessive blood pressure drop.

Symptoms

Lower blood pressure, postural dizziness, fatigue. Older patients: fall risk. With additional antihypertensives: bradycardia (pulse below 60/min).

Management

The combination is acceptable for short diazepam use with pulse and blood pressure monitoring. In older patients: lorazepam or oxazepam at minimum doses (short-acting, less accumulation risk).

Mechanism

NSAIDs weaken the antihypertensive effect of beta-blockers via renal prostaglandin suppression. Diclofenac is one of the most ulcerogenic NSAIDs with elevated cardiovascular risk.

Symptoms

Gradual blood pressure rise 1–2 weeks after starting the NSAID. In chronic kidney disease: risk of fluid retention and oedema.

Management

Avoid prolonged diclofenac use. For acute pain: short course (5–7 days) with pantoprazole cover. For chronic analgesia: paracetamol, celecoxib, or topical NSAIDs.

Mechanism

Additive bradycardia and atrioventricular (AV) conduction slowing. Used in atrial fibrillation and heart failure for ventricular rate control.

Symptoms

Lower blood pressure, postural dizziness, fatigue. Older patients: fall risk. With additional antihypertensives: bradycardia (pulse below 60/min).

Management

Standard regimen for atrial fibrillation with rapid ventricular response and heart failure. Check pulse and ECG at 1 and 4 weeks. If pulse drops below 50/min or second-degree AV block appears, adjust dose.

Mechanism

Empagliflozin (SGLT2 inhibitor) causes osmotic diuresis and mild hypovolaemia. Combined with a beta-blocker: additive orthostatic hypotension risk, especially in the first weeks.

Symptoms

Lower blood pressure, postural dizziness, fatigue. Older patients: fall risk. With additional antihypertensives: bradycardia (pulse below 60/min).

Management

The combination is part of guideline-directed therapy in heart failure with reduced ejection fraction and type 2 diabetes. In hypovolaemia (dehydration, vomiting, diarrhoea), temporarily stop empagliflozin. Check blood pressure and creatinine 2 weeks after start.

Mechanism

Standard combination in heart failure and hypertension. Additive hypotensive effect; furosemide causes hypokalaemia, amplifying arrhythmia risk with concomitant QT-prolonging drugs.

Symptoms

Lower blood pressure, postural dizziness, fatigue. Older patients: fall risk. With additional antihypertensives: bradycardia (pulse below 60/min).

Management

Standard combination. Check potassium and magnesium every 1–3 months. If potassium drops below 4.0 mmol/L, add a potassium-sparing diuretic (spironolactone) or potassium supplement. Check blood pressure and pulse 1–2 weeks after start.

Mechanism

Beta-blockers can mask the adrenergic warning signs of hypoglycaemia: fast pulse, palpitations, sweating (bisoprolol and glibenclamide SmPCs). The bisoprolol SmPC warns that with sulfonylureas, glibenclamide among them, the risk of severe hypoglycaemia may rise. Glibenclamide is long-acting and so causes severe hypoglycaemia more often than short-acting sulfonylureas, and in older people hypoglycaemia is harder to recognise (glibenclamide SmPC).

Symptoms

Sudden confusion, weakness, ataxia without preceding tachycardia or sweating. Older patients: risk of severe hypoglycaemia without warning symptoms.

Management

The combination can be used with caution (bisoprolol SmPC). Advise the patient with diabetes to monitor blood glucose carefully (bisoprolol SmPC) and explain in advance that on a beta-blocker the fast pulse, palpitations and sweating of hypoglycaemia may weaken or disappear (bisoprolol and glibenclamide SmPCs). In older people the starting and maintenance glibenclamide doses are chosen conservatively, because hypoglycaemia is more frequent and harder to notice. The patient always carries at least 20 g of glucose or sugar to treat hypoglycaemia at once (glibenclamide SmPC). The US Food and Drug Administration (FDA) also requires warning patients on oral antidiabetic drugs that bisoprolol may mask signs of hypoglycaemia, particularly a fast pulse (bisoprolol FDA label).

Mechanism

Additive hypotension (haloperidol blocks α1-adrenoceptors) and QT prolongation risk (haloperidol is a known QT prolonger).

Symptoms

Lower blood pressure, postural dizziness, syncope. ECG: QT prolongation. Older patients: fall risk.

Management

Avoid the combination, especially parenteral haloperidol. Alternative antipsychotics with minimal α1 and QT effect: olanzapine or aripiprazole. For acute delirium: dexmedetomidine.

Mechanism

Standard combination in hypertension – additive antihypertensive effect. Thiazide diuretic causes hypokalaemia.

Symptoms

Lower blood pressure, postural dizziness, fatigue. Older patients: fall risk. With additional antihypertensives: bradycardia (pulse below 60/min).

Management

Standard combination (fixed-dose product available). Check potassium 2–4 weeks after start and then annually. If potassium drops below 4.0 mmol/L, add a potassium-sparing component.

Mechanism

Similar to bisoprolol + ketorolac. Ibuprofen weakens the antihypertensive effect of the beta-blocker via renal prostaglandin blockade.

Symptoms

Gradual blood pressure rise 1–2 weeks after starting the NSAID. In chronic kidney disease: risk of fluid retention and oedema.

Management

For short ibuprofen courses (5–7 days), monitor blood pressure. For chronic analgesia: switch to paracetamol, celecoxib (with PPI cover), or topical NSAIDs.

Mechanism

Standard combination in hypertension – additive antihypertensive effect. Indapamide (thiazide-like diuretic) causes hypokalaemia.

Symptoms

Lower blood pressure, postural dizziness, fatigue. Older patients: fall risk. With additional antihypertensives: bradycardia (pulse below 60/min).

Management

Standard combination. Check potassium 2–4 weeks after start and then annually. If potassium drops below 4.0 mmol/L, add a potassium-sparing component.

Mechanism

Beta-blockers can make treating anaphylaxis to iodinated contrast harder – adrenaline becomes less effective due to β-blockade.

Symptoms

On anaphylaxis: resistance to standard adrenaline dose – persistent hypotension, facial and tongue swelling, bronchospasm.

Management

The beta-blocker is usually not stopped for a contrast study. Prepare higher adrenaline doses and glucagon (3–5 mg IV for refractory anaphylaxis). In patients with allergy history, consider premedication (methylprednisolone + antihistamine).

Mechanism

NSAIDs weaken the antihypertensive effect of beta-blockers via prostaglandin-dependent renal regulation (natriuresis). Ketorolac is the most potent NSAID.

Symptoms

Gradual blood pressure rise 1–2 weeks after starting the NSAID. In chronic kidney disease: risk of fluid retention and oedema.

Management

Ketorolac courses are limited to 5 days. Check blood pressure in the first days. In borderline hypertension, temporarily increase bisoprolol. For chronic analgesia: paracetamol or a short opioid course.

Mechanism

Besides its antibacterial action, linezolid is a reversible, non-selective inhibitor of monoamine oxidase (MAO), so it belongs to the MAO inhibitors (linezolid SmPC). The bisoprolol SmPC warns that MAO inhibitors, except MAO-B inhibitors, increase the blood pressure-lowering effect of beta-blockers but also raise the risk of hypertensive crises (bisoprolol SmPC).

Symptoms

Excessive drop in blood pressure: dizziness, weakness, feeling faint. The opposite reaction is also possible: a hypertensive crisis with a sharp rise in blood pressure and severe headache (bisoprolol SmPC).

Management

The combination is not prohibited, but the bisoprolol SmPC lists monoamine oxidase (MAO) inhibitors, except MAO-B inhibitors, among combinations that need assessment: blood pressure may either fall or rise sharply (bisoprolol SmPC). The linezolid SmPC describes linezolid as a non-selective MAO inhibitor (linezolid SmPC). So blood pressure and wellbeing are watched during a linezolid course in a patient on bisoprolol. In uncontrolled hypertension, linezolid is given only where blood pressure can be closely monitored (linezolid SmPC).

Mechanism

NSAIDs weaken the antihypertensive effect of beta-blockers. Meloxicam is less ulcerogenic than non-selective NSAIDs (preferential COX-2 activity), but the renal effect persists.

Symptoms

Gradual blood pressure rise 1–2 weeks after starting the NSAID. In chronic kidney disease: risk of fluid retention and oedema.

Management

For short meloxicam courses (5–7 days), monitor blood pressure. For chronic analgesia: switch to paracetamol or celecoxib (with PPI cover).

Mechanism

Methylprednisolone causes sodium and water retention via mineralocorticoid effect, reducing the antihypertensive effect of the beta-blocker.

Symptoms

Gradual blood pressure rise 2–4 weeks after starting the glucocorticoid. In heart failure: oedema, weight gain.

Management

For short methylprednisolone courses (up to 7 days), no adjustment. For prolonged systemic therapy, increase bisoprolol or add a diuretic (hydrochlorothiazide, indapamide) with blood pressure monitoring every 2 weeks.

Mechanism

Additive hypotension and sedation. Mirtazapine blocks α2-adrenergic and 5-HT2 receptors, causing orthostatic effects.

Symptoms

Lower blood pressure, postural dizziness, fatigue. Older patients: fall risk.

Management

The combination is acceptable at low mirtazapine doses (15–30 mg). Warn the patient about drowsiness and orthostatic dizziness, especially in the first 1–2 weeks. Check blood pressure standing and sitting.

Mechanism

Additive bradycardia and hypotension. Morphine reduces sympathetic tone via μ-opioid receptors.

Symptoms

Lower blood pressure, postural dizziness, fatigue. Older patients: fall risk. With additional antihypertensives: bradycardia (pulse below 60/min).

Management

The combination is acceptable in palliative care and acute coronary syndrome (standard practice). Titrate morphine from a low dose; monitor pulse, blood pressure, and saturation.

Mechanism

NSAIDs weaken the antihypertensive effect of beta-blockers via renal prostaglandin suppression.

Symptoms

Gradual blood pressure rise 1–2 weeks after starting the NSAID. In chronic kidney disease: risk of fluid retention and oedema.

Management

For short naproxen courses (5–7 days), monitor blood pressure. For chronic analgesia: switch to paracetamol or celecoxib (with PPI cover).

Mechanism

Prednisolone causes sodium and water retention via mineralocorticoid effect, reducing bisoprolol's antihypertensive effect.

Symptoms

Gradual blood pressure rise 2–4 weeks after starting the glucocorticoid. In heart failure: oedema, weight gain.

Management

For short prednisolone courses (up to 7 days), no adjustment. For prolonged systemic therapy, increase bisoprolol or add a diuretic with blood pressure monitoring every 2 weeks.

Mechanism

Additive hypotension (quetiapine blocks α1-adrenoceptors) and additive bradycardia.

Symptoms

Lower blood pressure, postural dizziness, fatigue. Older patients: fall risk.

Management

The combination is acceptable at low quetiapine doses (≤300 mg/day). Check pulse and blood pressure 1–2 weeks after start. In older patients, olanzapine or aripiprazole (less α1-blockade) is preferable.

Mechanism

Rifampicin induces CYP3A4, modestly lowering bisoprolol plasma levels (bisoprolol is metabolised 50% via CYP3A4 and 50% renally). The effect is weaker than for fully CYP-dependent beta-blockers.

Symptoms

Gradual blood pressure rise or return of anginal symptoms 2–3 weeks after starting rifampicin. In tachyarrhythmias: return of symptoms.

Management

During anti-TB therapy, increase bisoprolol by 50% with blood pressure and pulse monitoring. After rifampicin stops, taper back gradually (induction persists for 2 weeks).

Mechanism

Sildenafil is a vasodilator via PDE5 blockade. Combined with bisoprolol: risk of symptomatic hypotension, especially with the first dose.

Symptoms

Lower blood pressure, postural dizziness, fatigue. Older patients: fall risk.

Management

The combination is acceptable in stable hypertension with a well-titrated beta-blocker. Take the first sildenafil dose lying down; do not exceed 25–50 mg. Warn the patient about orthostatic hypotension.

Mechanism

Standard combination in heart failure with reduced ejection fraction – additive antihypertensive effect. Spironolactone retains potassium, reducing arrhythmia risk on a beta-blocker.

Symptoms

Lower blood pressure, postural dizziness, fatigue. Older patients: fall risk.

Management

Standard combination. Check potassium and creatinine 1 week after start, then monthly. If potassium exceeds 5.5 mmol/L, reduce spironolactone.

Mechanism

Bisoprolol is cardioselective, but at high doses (above 10 mg/day) partially blocks β2-receptors and may weaken theophylline's bronchodilator effect in asthma or COPD.

Symptoms

Return of dyspnoea, wheezing, night cough. In severe asthma, bronchospasm is possible.

Management

In mild asthma or COPD, bisoprolol up to 10 mg is acceptable with pulmonary function monitoring. In severe airway obstruction, replace bisoprolol with a non-β2 cardiovascular alternative (amlodipine, ivabradine in heart failure with tachycardia).

Mechanism

Standard combination in heart failure with reduced ejection fraction. Additive antihypertensive effect and complementary neurohormonal blockade.

Symptoms

On starting, in older or hypovolaemic patients: symptomatic hypotension, dizziness. Bisoprolol bradycardia is amplified.

Management

Start both at minimal doses with up-titration every 2 weeks to target. Check standing/sitting BP, heart rate, creatinine and potassium at 2 weeks. In heart failure, target maximum tolerated doses (bisoprolol up to 10 mg, valsartan up to 320 mg). Outcome evidence base is extensive.

Mechanism

Paracetamol and bisoprolol are metabolised by different pathways. No direct pharmacokinetic interaction.

Symptoms

The combination usually causes no specific symptoms. Each drug's individual side effects remain.

Management

No dose adjustment needed. Paracetamol remains the analgesic of choice in patients on bisoprolol.