tamsulosin hydrochloride: clinical use

Prescribing considerations

• Exclude other causes of lower urinary tract symptoms before treatment; prostate examination and PSA assessment may be appropriate.
• Assess postural symptoms and concurrent blood-pressure-lowering medicines.
• Ask about planned cataract or glaucoma surgery and communicate current or previous exposure to the ophthalmic team.
• Review CYP3A4 inhibitors and possible CYP2D6 poor-metaboliser status where clinically relevant.
• Use caution in severe renal impairment because this population has not been adequately studied.

Contraindications and cautions

• Hypersensitivity to tamsulosin or product excipients, including previous drug-induced angioedema where specified
• History of orthostatic hypotension
• Severe hepatic insufficiency

Monitoring

• Urinary symptom response and evidence of an alternative diagnosis
• Dizziness, postural hypotension or syncope
• Prostate assessment and PSA where clinically appropriate
• Adverse sexual effects and medicine interactions
• Cataract or glaucoma surgical plans

Clinical pharmacology

Tamsulosin is a selective, competitive postsynaptic alpha-1 antagonist with particular activity at alpha-1A receptors. Relaxation of prostatic and urethral smooth muscle improves urinary flow. It is highly protein-bound and undergoes slow hepatic metabolism involving CYP3A4 and CYP2D6.

Formulation and product differences

• Products include prolonged-release tablets and modified- or prolonged-release hard capsules.
• Food instructions are product-specific: some products may be taken with or without food, while others specify administration after the first meal.
• Modified- or prolonged-release formulations must be swallowed intact.
• Excipients differ: the selected tablet contains lactose, while the SUN Pharma capsule contains colouring agents that may cause allergic reactions.

Capsule

Route: Oral

Strengths: 400 micrograms

Modified-release tablet

Route: Oral

Strengths: 400 micrograms