CLINICAL USE

Beta-adrenoceptor blocker: Hypertension Angina Glaucoma Migraine prophylaxis

DOSE IN NORMAL RENAL FUNCTION

Hypertension: 10–60 mg daily, doses >30 mg in divided doses Angina: 5–30 mg twice daily Post MI: 5–10 mg twice daily Migraine:

  • 10 to 20     : mg daily in 1–2 divided doses

    PHARMACOKINETICS

  • Molecular weight                           : 432.5
  • %Protein binding                           : 10
  • %Excreted unchanged in urine     : 5
  • Volume of distribution (L/kg)       : 1.7
  • half-life – normal/ESRD (hrs)      : 4/Unchanged

    DOSE IN RENAL IMPAIRMENT

    GFR (mL/MIN)

  • 20 to 50     : Dose as in normal renal function
  • 10 to 20     : Dose as in normal renal function. Start with lowest dose and titrate according to response
  • <10           : Dose as in normal renal function. Start with lowest dose and titrate according to response

    DOSE IN PATIENTS UNDERGOING RENAL REPLACEMENT THERAPIES

  • CAPD                : Not dialysed. Dose as in GFR <10 mL/min
  • HD                     : Not dialysed. Dose as in GFR <10 mL/min
  • HDF/high flux   : Unknown dialysability. Dose as in GFR <10 mL/min
  • CAV/VVHD      : Unknown dialysability. Dose as in GFR 10 to 20 mL/min

    IMPORTANT DRUG INTERACTIONS

    Potentially hazardous interactions with other drugs

  • Anaesthetics: enhanced hypotensive effect
  • Analgesics: NSAIDs antagonise hypotensive effect
  • Anti-arrhythmics: increased risk of myocardial depression and bradycardia; increased risk of bradycardia, myocardial depression and AV block with amiodarone
  • Antidepressants: enhanced hypotensive effect with MAOIs Antihypertensives: enhanced hypotensive effect; increased risk of withdrawal hypertension with clonidine; increased risk of first dose hypotensive effect with post-synaptic alpha-blockers such as prazosin
  • Antimalarials: increased risk of bradycardia with mefloquine Antipsychotics enhanced hypotensive effect with phenothiazines
  • Calcium-channel blockers: increased risk of bradycardia and AV block with diltiazem; hypotension and heart failure possible with nifedipine and nisoldipine; asystole, severe hypotension and heart failure with verapamil
  • Diuretics: enhanced hypotensive effect
  • Moxisylyte: possible severe postural hypotension
  • Sympathomimetics: severe hypertension with adrenaline and noradrenaline and possibly with dobutamine Tropisetron: increased risk of ventricular arrhythmias – use with caution

    ADMINISTRATION

    Reconstition

    Route

    Oral, topical

    Rate of Administration

    Comments

    OTHER INFORMATION

    Timolol is more hydrophilic than lipophilic

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