Harnal D

Harnal D

tamsulosin

Manufacturer:

Astellas
Full Prescribing Info
Contents
Tamsulosin HCl.
Action
Pharmacology: In a receptor-binding assay using human prostate preparations, tamsulosin hydrochloride was 2.2 times more potent than prazosin hydrochloride and 40 times more so than phentolamine mesylate in α1-receptor blocking activity.
Blockade of α1-Adrenergic Receptors: In a receptor-binding assay using isolated rat cerebral membrane and an in vitro experiment using isolated rabbit aorta, tamsulosin hydrochloride inhibited α1-receptors selectively and competitively.
Its action was 1/2.2 to 22 times more potent than prazosin hydrochloride and 45-140 times more potent than phentolamine mesylate. In vitro experiments using isolated rabbit aorta, isolated rat vas deferens and isolated guinea pig intestine, tamsulosin hhydrochloride proved to be 5400-24,000 times more selective for α1-receptors than for α2-receptors.
Effect on the Lower Urinary Tract (Urethra and Urinary Bladder) and Prostate: In a receptor-binding assay using isolated smooth muscle from the rabbit urethra, prostate and urinary bladder base, tamsulosin hydrochloride was 23-98 times more potent than prazosin hydrochloride in α1-receptor blocking activity, and 87-320 times more potent than phentolamine mesylate. In anesthetized dogs, the drug inhibited the α1-agonist (phenylephrine)-induced increase in intraurethral pressure with 13 times greater potency than the increase in diastolic blood pressure.
Improvement of Bladder Outlet Disturbance: In anesthetized male dogs, tamsulosin hydrochloride decreased urethral pressure in the prostatic zone of the intraurethral pressure curve. In anesthetized rats, however, tamsulosin did not affect rhythmic bladder contraction or threshold intravesical pressure.
Mechanism of Action: Tamsulosin hydrochloride decreases urethral pressure in the prostatic zone of the intraurethral pressure curve by inhibiting α1-receptors in the urethra and prostate, thus improving bladder outlet obstruction associated with benign prostatic hyperplasia.
Indications/Uses
Bladder outlet disturbance associated with benign prostatic hyperplasia.
Dosage/Direction for Use
Adults: Usual Dosage: 0.2-0.4 mg once daily after meals.
Overdosage
In case of acute hypotension occuring after the overdosage, cardiovascular support should be given. Blood pressure can be restored and the heart rate brought back to normal by lying the patient down.
If this does not help, then volume expanders, when necessary, vasopressors could be employed. Renal function should be monitored and general supportive measures applied. Dialysis is unlikely to be of help as tamsulosin is very highly bound to plasma proteins.
Measures eg, emesis, can be taken to impede absorption. When large quantities are involved, gastric lavage can be applied and activated charcoal and an osmotic laxative eg, sodium sulfate can be administered.
Contraindications
Known hypersensitivity to tamsulosin hydrochloride or to any of the components of Harnal D; severe hepatic insufficiency.
Special Precautions
General: The tablets disintegrate in the mouth, but are not absorbed through the oral mucosa. Therefore, the patients should be instructed to swallow the dissolved tablet with saliva or a drink of water. Use with caution concerning dosage and administration. Overdosage may cause a decrease in blood pressure.
Blood pressure in the orthostatic position may decrease. Patients must be watched for any changes in blood pressure occuring with postural change.
Harnal D does not eliminate the cause of the disease, but gives symptomatic relief. If the expected response is not noted, surgical therapy or other alternative procedures should be considered.
Before the start of treatment, patients should be asked whether they are taking any antihypertensive drugs. If any such drugs are used, blood pressure during treatment should be monitored closely. If a decrease in blood pressure is observed, the dose should be reduced, the treatment discontinued or other appropriate measures taken.
Intraoperative Floopy Iris Syndrome (IFIS), a variant of small pupil syndrome, considered to be due to α1-blocking action has been observed during cataract and glaucoma surgery in some patients on or previously treated with tamsulosin. Ophtalmologists should be aware of possible occurance of IFIS during cataract and glaucoma surgery.
Tamsulosin hydrochloride 0.4 mg should be used with caution in combination with strong inhibitors of CYP3A4. Tamsulosin hydrochloride 0.4 mg should not be used in combination with strong inhibitors of CYP3A4 in patients known to be CYP2D6 poor metabolizers.
Use in patients with micturition syncope is not advised.
Effects on the Ability to Drive or Operate Machinery: Since Harnal D may produce dizziness, patients should be cautioned about driving, operating machinery or performing hazardous tasks.
Adverse Reactions
(Rarely <0.1%; infrequently 0.1 to <5%; incidence unknown.)
Psychoneurologic: Dizziness on standing up, headache, sleepiness may occur infrequently.
Cardiovascular: Blood pressure dropped, orthostatic hypotension, tachycardia, palpitation may occur infrequently.
Hypersensitivity: Itching and rash may occur infrequently. Administration should be discontinued if such symptoms occur.
Gastrointestinal: Nausea/vomiting, thirst, constipation, stomach heaviness, diarrhea, dysphagia, gastralgia, anorexia may occur infrequently.
Hepatic Dysfunction or Jaundice (Incidence Unknown): As increases of AST (GOT), ALT (GPT) or jaundice may appear.
Syncope Unconsciousness (Incidence Unknown): As transient unconsciousness or etc may appear with the decrease of blood pressure.
Others: Edema, urinary incontinence, burning sensation of pharynx, general malaise, nasal congestion may occur infrequently.
Drug Interactions
When co-administered with others antihypertensives drugs, should take precautions by decreasing doses as orthostatic hypotension may occur.
Concomitant use of phosphodiesterase-5 inhibitors, sildenafil citrate, vardenafil hydrochloride hydrate, etc may cause hypotension.
Caution For Usage
Patients should be instructed not to chew the granules contained within.
Storage
Store at room temperature in tight container.
ATC Classification
G04CA02 - tamsulosin ; Belongs to the class of alpha-adrenoreceptor antagonists. Used in the treatment of benign prostatic hypertrophy.
Presentation/Packing
Dispersible tab 0.2 mg x 2 x 14's.
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