- Drugs List
- Therapeutic Indications
- Precautions and Warnings
- Pregnancy and Lactation
- Side Effects
Oral formulations of terazosin hydrochloride.
Hypertension - mild to moderate
Lower urinary obstruction due to benign prostatic hyperplasia
Mild to moderate hypertension: Monotherapy or in combination with thiazide diuretics and/or other antihypertensive drugs.
Symptomatic treatment of lower urinary obstruction caused by benign prostatic hyperplasia.
An initial dose of 1mg daily before bedtime. The daily dose can then be doubled at approximately weekly intervals to achieve the desired response.
A typical maintenance dose is 2mg to 10mg once daily.
Benign prostatic hyperplasia:
An initial dose of 1mg daily before bedtime. The daily dose can then be doubled at approximately weekly or fortnightly intervals as necessary to achieve the desired response.
A typical maintenance dose is 5mg to 10mg once daily.
Additional Dosage Information
If using terazosin in combination with thiazide diuretics or other antihypertensive agents, the dose of terazosin should be reduced and re-titration carried out if necessary.
Review patient response at each dose increase as side effects may occur at each stage. If these persist, consider a dose reduction.
Children under 18 years
Congestive cardiac failure secondary to mechanical obstruction
History of micturition syncope - if treating benign prostatic hyperplasia
Precautions and Warnings
Patients over 65 years
Predisposition to orthostatic hypotension
Glucose-galactose malabsorption syndrome
High output cardiac failure
History of postural hypotension
Ischaemic heart disease
Left ventricular failure
Pulmonary oedema due to aortic stenosis
Pulmonary oedema due to mitral stenosis
Right sided cardiac insufficiency due to PE or pericardial effusion
Advise hypotension/syncope may affect ability to drive/operate machinery
Advise patient not to drive/operate machinery after first or dose changes
Benign prostatic hyperplasia: Exclude prostate carcinoma before treatment
Exclude urinary tract infection before treatment of BPH
Not all available brands are licensed for all indications
Some formulations contain sunset yellow (E110); may cause allergic reaction
Monitor blood pressure after dose increases
Profound hypotension can occur,especially after initial dose-monitor
Review therapy after 4 weeks
Intraoperative Floppy Iris Syndrome has been reported in cataract surgery
May cause postural hypotension especially in elderly
Seek immediate medical attention if priapism occurs
Retitration of dosage required after interruption of therapy
Exclude concomitant obstruction of the upper urinary tract before treatment.
Pregnancy and Lactation
Terazosin is contraindicated in pregnancy. There is insufficient study data to conclude safety of terazosin during pregnancy. Other drugs with a greater safety profile should be considered first.
Animal studies in terazosin have shown no teratogenic effect. There have been incidence of foetal resorption in rat and rabbit studies, and low foetal weight observed in rabbits. At a dose greater than 75 times the recommended maximum human dose a significant increase in mortality in perinatal and postnatal rat pups has been seen. Terazosin may also increase the duration of pregnancy and inhibit labour.
The use of all medication in pregnancy should be avoided whenever possible; particularly in the first trimester. Non-drug treatments should also be considered. When essential, a medication with the best safety record over time should be chosen, employing the lowest effective dose for the shortest possible time. Polypharmacy should be avoided. Teratogens taken in the pre-embryonic period, often quoted as lasting until 14 to 17 days post-conception, are believed to have an all-or-nothing effect. Where drugs have a short half-life, and when the date of conception is certain, this may allow women to be reassured where drug exposure has occurred within this time frame. Further advice may be available from the UK National Teratology Information Service (NTIS) and through ToxBase, available via password on the internet ( www.toxbase.org ) or if this is unavailable at the backup site ( www.toxbasebackup.org ).
Use terazosin with caution in breastfeeding. There is limited data to support the use of terazosin during breastfeeding.
The molecular weight of terazosin is low enough that excretion into breast milk should be expected. The effects on the nursing infant from exposure to the drug from breast milk are unknown. An alternative antihypertensive drug may be preferred, especially while nursing a newborn or preterm infant.
Specialist advice is available from the UK Drugs in Lactation Advisory Service at https://www.midlandsmedicines.nhs.uk/content.asp?section=6&subsection=17&pageIdx=1
Advise patients that their ability to drive or operate machinery may be impaired by dizziness, light-headedness or drowsiness. They should avoid driving or operating machinery for about 12 hours after the initial dose or each subsequent dose increase or if they are aware that they are affected by these effects.
Advise patient to seek immediate medical attention if priapism occurs.
Decrease in haematocrit
Decrease in haemoglobin
Decreased serum albumin
Decreased total serum protein
Intraoperative floppy iris syndrome
Urinary tract infections
White blood cell count decreased
The following number will direct the caller to the relevant local centre (0844) 892 0111
Last Full Review Date: January 2018
Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk, 10th edition (2015) ed. Briggs, G., Freeman, R. Wolters Kluwer Health, Philadelphia.
Drugs During Pregnancy and Lactation: Treatment Options and Risk Assessment, 3rd edition (2015) ed. Schaefer, C., Peters, P. and Miller, R. Elsevier, London.
NICE Evidence Services Available at: www.nice.org.uk Last accessed: 10 January 2018
US National Library of Medicine. Toxicology Data Network. Drugs and Lactation Database (LactMed).
Available at: https://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?LACT
Terazosin Last revised: 10 March 2015
Last accessed: 18 January 2018
Summary of Product Characteristics: Benph tablets 2mg. Generics UK Ltd t/a Mylan. Revised August 2015.
Summary of Product Characteristics: Benph tablets 5mg. Generics UK Ltd t/a Mylan. Revised August 2015.
Summary of Product Characteristics: Hytrin tablets 2mg. Concordia International. Revised February 2016.
Summary of Product Characteristics: Hytrin tablets 5mg. Concordia International. Revised February 2016.
Summary of Product Characteristics: Hytrin tablets 10mg. Concordia International. Revised February 2016.
Summary of Product Characteristics: Terazosin Teva tablets 2mg. Teva Pharma. Revised July 2015.
Summary of Product Characteristics: Terazosin Teva tablets 5mg. Teva Pharma. Revised July 2015.
Summary of Product Characteristics: Terazosin Teva tablets 10mg. Teva Pharma. Revised July 2015.
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Medscape UK | Univadis prescription drug monographs & interactions are based on FDB Multilex Content