Dosing & Uses
Benign Prostatic Hypertrophy
Indicated for treatment of signs and symptoms of benign prostatic hyperplasia (BPH)
0.4 mg PO qDay; take 30 minutes after same meal each day
If inadequate response after 2-4 weeks, may increase to 0.8 mg qDay
If therapy interrupted or discontiniued for several days, resume at 0.4 mg/day and increase if needed
Bladder Outlet Obstruction (Off-label)
Relief of symptoms
0.4 mg PO qDay
Ureteral Stones (Off-label)
Facilitation of kidney stone expulsion
0.4 mg PO qDay; discontinued after successful expulsion (average, 1-2 weeks)
Double-blind, placebo-controlled trial found tamsulosin did not significantly increase stone passage rate compared with placebo for stones <9 mm (JAMA Intern Med. 2018 Aug 1;178(8):1051-1057)
Dosing Modifications
Renal impairment
- CrCl ≥10 mL/min: Dosage adjustment not necessary
- CrCl <10 mL/min: Not studied
Hepatic impairment
- Mild to moderate: Dosage adjustment not necessary
- Severe: Not studied
Dosing Considerations
Not indicated for hypertension
Safety and efficacy not established
Interactions
Interaction Checker
Contraindicated
Serious
Significant - Monitor Closely
Minor
Contraindicated (2)
- mavorixafor
mavorixafor will increase the level or effect of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Contraindicated. Mavorixafor (a strong CYP2D6 inhibitor) is contraindicated with drugs that are highly dependent on CYP2D6 for clearance.
- ombitasvir/paritaprevir/ritonavir & dasabuvir (DSC)
ombitasvir/paritaprevir/ritonavir & dasabuvir (DSC) will increase the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Increased risk for hypotensio
Serious (45)
- alfuzosin
alfuzosin, tamsulosin. Either increases effects of the other by additive vasodilation. Avoid or Use Alternate Drug. Risk of hypotension.
- apalutamide
apalutamide will decrease the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of apalutamide, a strong CYP3A4 inducer, with drugs that are CYP3A4 substrates can result in lower exposure to these medications. Avoid or substitute another drug for these medications when possible. Evaluate for loss of therapeutic effect if medication must be coadministered. Adjust dose according to prescribing information if needed.
- atazanavir
atazanavir increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Potential for increased toxicity. .
- carbamazepine
carbamazepine will decrease the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- ceritinib
ceritinib will increase the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- chloramphenicol
chloramphenicol will increase the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
- clarithromycin
clarithromycin increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- cobicistat
cobicistat will increase the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- conivaptan
conivaptan increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- dacomitinib
dacomitinib will increase the level or effect of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. Avoid use with CYP2D6 substrates where minimal increases in concentration of the CYP2D6 substrate may lead to serious or life-threatening toxicities.
- darunavir
darunavir increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- doxazosin
doxazosin, tamsulosin. Either increases effects of the other by additive vasodilation. Avoid or Use Alternate Drug. Risk of hypotension.
- enzalutamide
enzalutamide will decrease the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- fexinidazole
fexinidazole will increase the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Fexinidazole inhibits CYP3A4. Coadministration may increase risk for adverse effects of CYP3A4 substrates.
- fosamprenavir
fosamprenavir increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- fosphenytoin
fosphenytoin will decrease the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- givosiran
givosiran will increase the level or effect of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP2D6 substrates with givosiran. If unavoidable, decrease the CYP2D6 substrate dosage in accordance with approved product labeling.
- idelalisib
idelalisib will increase the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Idelalisib is a strong CYP3A inhibitor; avoid coadministration with sensitive CYP3A substrates
- imatinib
imatinib increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- isoniazid
isoniazid increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- itraconazole
itraconazole increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Not recommended during and 2 weeks after itraconazole treatment. .
- ivosidenib
ivosidenib will decrease the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP3A4 substrates with ivosidenib or replace with alternative therapies. If coadministration is unavoidable, monitor patients for loss of therapeutic effect of these drugs.
- ketoconazole
ketoconazole increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Potential for increased toxicity.
- levoketoconazole
levoketoconazole increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Potential for increased toxicity.
- lonafarnib
lonafarnib will increase the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration with sensitive CYP3A substrates. If coadministration unavoidable, monitor for adverse reactions and reduce CYP3A substrate dose in accordance with product labeling.
- lopinavir
lopinavir increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Potential for increased toxicity.
- nefazodone
nefazodone increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- nelfinavir
nelfinavir increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- nicardipine
nicardipine increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- nirmatrelvir/ritonavir
nirmatrelvir/ritonavir will increase the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Tamsulosin metabolized mainly by CYP3A4 and to a lesser extent by CYP2D6. Pause tamsulosin and restart 3 days after completing nirmatrelvir/ritonavir given that CYP3A4 inhibition takes several days to resolve.
- phenobarbital
phenobarbital will decrease the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- phenoxybenzamine
phenoxybenzamine, tamsulosin. Either increases effects of the other by additive vasodilation. Avoid or Use Alternate Drug. Risk of hypotension.
- phentolamine
phentolamine, tamsulosin. Either increases effects of the other by additive vasodilation. Avoid or Use Alternate Drug. Risk of hypotension.
- phenytoin
phenytoin will decrease the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- posaconazole
posaconazole increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- prazosin
prazosin, tamsulosin. Either increases effects of the other by additive vasodilation. Avoid or Use Alternate Drug. Risk of hypotension.
- primidone
primidone will decrease the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- quinidine
quinidine increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- rifampin
rifampin will decrease the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- ritonavir
ritonavir increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- silodosin
silodosin, tamsulosin. Either increases effects of the other by additive vasodilation. Avoid or Use Alternate Drug. Risk of hypotension.
- terazosin
terazosin, tamsulosin. Either increases effects of the other by additive vasodilation. Avoid or Use Alternate Drug. Risk of hypotension.
- tipranavir
tipranavir increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- tucatinib
tucatinib will increase the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid concomitant use of tucatinib with CYP3A substrates, where minimal concentration changes may lead to serious or life-threatening toxicities. If unavoidable, reduce CYP3A substrate dose according to product labeling.
- voriconazole
voriconazole increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
Monitor Closely (97)
- abiraterone
abiraterone increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Avoid coadministration of abiraterone with substrates of CYP2D6. If alternative therapy cannot be used, exercise caution and consider a dose reduction of the CYP2D6 substrate.
- amifostine
amifostine, tamsulosin. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration with blood pressure lowering agents may increase the risk and severity of hypotension associated with amifostine. When amifostine is used at chemotherapeutic doses, withhold blood pressure lowering medications for 24 hr prior to amifostine; if blood pressure lowering medication cannot be withheld, do not administer amifostine.
- amiodarone
amiodarone increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dose reduction may be neeed for coadministered drugs that are predominantly metabolized by CYP3A.
amiodarone increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. - amobarbital
amobarbital will decrease the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- aprepitant
aprepitant increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dose reduction may be needed for coadministered drugs that are predominantly metabolized by CYP3A.
- avanafil
avanafil, tamsulosin. Either increases effects of the other by additive vasodilation. Use Caution/Monitor. Risk of hypotension.
- bicalutamide
bicalutamide increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dose reduction may be needed for coadministered drugs that are predominantly metabolized by CYP3A.
- bortezomib
bortezomib increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- bosentan
bosentan will decrease the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- bupropion
bupropion increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- cenobamate
cenobamate will decrease the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Increase dose of CYP3A4 substrate, as needed, when coadministered with cenobamate.
- chloroquine
chloroquine increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- chlorpromazine
chlorpromazine increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- cimetidine
cimetidine increases levels of tamsulosin by decreasing renal clearance. Use Caution/Monitor. Decreases tamsulosin clearance by 26% resulting in increased AUC (44%).
cimetidine increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. - cinacalcet
cinacalcet increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- clobazam
clobazam increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- clomipramine
clomipramine increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- clozapine
clozapine increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- cocaine topical
cocaine topical increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- crizotinib
crizotinib increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dose reduction may be needed for coadministered drugs that are predominantly metabolized by CYP3A.
- crofelemer
crofelemer increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Crofelemer has the potential to inhibit CYP3A4 at concentrations expected in the gut; unlikely to inhibit systemically because minimally absorbed.
- cyclosporine
cyclosporine increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dose reduction may be needed for coadministered drugs that are predominantly metabolized by CYP3A.
- dabrafenib
dabrafenib will decrease the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.
- danazol
danazol will increase the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- darifenacin
darifenacin increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- desipramine
desipramine increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dose reduction may be needed for coadministered drugs that are predominantly metabolized by CYP3A.
desipramine increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. - dexmedetomidine
dexmedetomidine increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- diltiazem
diltiazem increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dose reduction may be needed for coadministered drugs that are predominantly metabolized by CYP3A.
- diphenhydramine
diphenhydramine increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- disulfiram
disulfiram increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- dronedarone
dronedarone increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dose reduction may be needed for coadministered drugs that are predominantly metabolized by CYP3A.
dronedarone increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. - duloxetine
duloxetine increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- duvelisib
duvelisib will increase the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with duvelisib increases AUC of a sensitive CYP3A4 substrate which may increase the risk of toxicities of these drugs. Consider reducing the dose of the sensitive CYP3A4 substrate and monitor for signs of toxicities of the coadministered sensitive CYP3A substrate.
- efavirenz
efavirenz increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dose reduction may be needed for coadministered drugs that are predominantly metabolized by CYP3A.
- elagolix
elagolix decreases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Elagolix is a weak-to-moderate CYP3A4 inducer. Monitor CYP3A substrates if coadministered. Consider increasing CYP3A substrate dose if needed.
- eliglustat
eliglustat increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Monitor therapeutic drug concentrations, as indicated, or consider reducing the dosage of the concomitant drug and titrate to clinical effect.
- elvitegravir/cobicistat/emtricitabine/tenofovir DF
elvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Cobicistat is a CYP3A4 inhibitor; contraindicated with CYP3A4 substrates for which elevated plasma concentrations are associated with serious and/or life-threatening events.
elvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Cobicistat is a CYP2D6 inhibitor; caution with CYP2D6 substrates for which elevated plasma concentrations are associated with serious and/or life-threatening events. - encorafenib
encorafenib, tamsulosin. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Encorafenib both inhibits and induces CYP3A4 at clinically relevant plasma concentrations. Coadministration of encorafenib with sensitive CYP3A4 substrates may result in increased toxicity or decreased efficacy of these agents.
- erythromycin base
erythromycin base increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dose reduction may be needed for coadministered drugs that are predominantly metabolized by CYP3A.
- erythromycin ethylsuccinate
erythromycin ethylsuccinate increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dose reduction may be needed for coadministered drugs that are predominantly metabolized by CYP3A.
- erythromycin lactobionate
erythromycin lactobionate increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dose reduction may be needed for coadministered drugs that are predominantly metabolized by CYP3A.
- erythromycin stearate
erythromycin stearate increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dose reduction may be needed for coadministered drugs that are predominantly metabolized by CYP3A.
- etravirine
etravirine will decrease the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- fedratinib
fedratinib will increase the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP3A4 substrates as necessary.
fedratinib will increase the level or effect of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP2D6 substrates as necessary. - fluconazole
fluconazole increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dose reduction may be needed for coadministered drugs that are predominantly metabolized by CYP3A.
- fluoxetine
fluoxetine increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- fosaprepitant
fosaprepitant increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dose reduction may be needed for coadministered drugs that are predominantly metabolized by CYP3A.
- grapefruit
grapefruit increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dose reduction may be needed for coadministered drugs that are predominantly metabolized by CYP3A.
- haloperidol
haloperidol increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- iloperidone
iloperidone increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Iloperidone is a time-dependent CYP3A inhibitor and may lead to increased plasma levels of drugs predominantly eliminated by CYP3A4.
- iloprost
iloprost, tamsulosin. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. When administering iloprost IV, consider temporary discontinuation of concomitant vasodilators or other medications that reduce blood pressure to mitigate potential additive hypotensive effects. If hypotension persists despite discontinuing other antihypertensives and fluid resuscitation, consider iloprost dose reduction or discontinuation.
- imatinib
imatinib increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- imipramine
imipramine increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- isoniazid
isoniazid increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- istradefylline
istradefylline will increase the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Istradefylline 40 mg/day increased peak levels and AUC of CYP3A4 substrates in clinical trials. This effect was not observed with istradefylline 20 mg/day. Consider dose reduction of sensitive CYP3A4 substrates.
- ketoconazole
ketoconazole increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- lapatinib
lapatinib increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dose reduction may be needed for coadministered drugs that are predominantly metabolized by CYP3A.
- larotrectinib
larotrectinib will increase the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- lenacapavir
lenacapavir will increase the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Lencapavir may increase CYP3A4 substrates initiated within 9 months after last SC dose of lenacapavir, which may increase potential risk of adverse reactions of CYP3A4 substrates.
- levoketoconazole
levoketoconazole increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- lidocaine
lidocaine increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dose reduction may be needed for coadministered drugs that are predominantly metabolized by CYP3A.
lidocaine increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. - lopinavir
lopinavir increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- lorcaserin
lorcaserin increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- lorlatinib
lorlatinib will decrease the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- methadone
methadone increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- methimazole
methimazole increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- metronidazole
metronidazole increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dose reduction may be needed for coadministered drugs that are predominantly metabolized by CYP3A.
- mifepristone
mifepristone will increase the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- mitotane
mitotane decreases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Mitotane is a strong inducer of cytochrome P-4503A4; monitor when coadministered with CYP3A4 substrates for possible dosage adjustments.
- nafcillin
nafcillin will decrease the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- nefazodone
nefazodone increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- nicardipine
nicardipine increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- oxymetazoline topical
oxymetazoline topical increases and tamsulosin decreases sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- paroxetine
paroxetine increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- pseudoephedrine
pseudoephedrine decreases effects of tamsulosin by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.
- pyrimethamine
pyrimethamine increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- quinidine
quinidine increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- quinine
quinine increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- ranolazine
ranolazine increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- ribociclib
ribociclib will increase the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- rifabutin
rifabutin will decrease the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- rifapentine
rifapentine will decrease the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- ritonavir
ritonavir increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- rolapitant
rolapitant will increase the level or effect of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Rolapitant may increase plasma concentrations of CYP2D6 substrates for at least 28 days following rolapitant administration.
- rucaparib
rucaparib will increase the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Adjust dosage of CYP3A4 substrates, if clinically indicated.
- sertraline
sertraline increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- sildenafil
sildenafil, tamsulosin. Either increases effects of the other by additive vasodilation. Use Caution/Monitor. Risk of hypotension.
- stiripentol
stiripentol, tamsulosin. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Stiripentol is a CYP3A4 inhibitor and inducer. Monitor CYP3A4 substrates coadministered with stiripentol for increased or decreased effects. CYP3A4 substrates may require dosage adjustment.
- tadalafil
tadalafil, tamsulosin. Either increases effects of the other by additive vasodilation. Use Caution/Monitor. Risk of hypotension.
- tazemetostat
tazemetostat will decrease the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- tecovirimat
tecovirimat will decrease the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Tecovirimat is a weak CYP3A4 inducer. Monitor sensitive CYP3A4 substrates for effectiveness if coadministered.
- terbinafine
terbinafine will increase the level or effect of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Assess need to reduce dose of CYP2D6-metabolized drug.
- thioridazine
thioridazine increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- tranylcypromine
tranylcypromine increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- trazodone
trazodone increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- vardenafil
vardenafil, tamsulosin. Either increases effects of the other by additive vasodilation. Use Caution/Monitor. Risk of hypotension.
- viloxazine
viloxazine will increase the level or effect of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Viloxazine (a weak CYP2D6 inhibitor) may increase systemic exposure of CYP2D6 substrates. Monitor and adjust dose of substrate as clinically indicated.
Minor (6)
- acetazolamide
acetazolamide will increase the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- anastrozole
anastrozole will increase the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- benazepril
tamsulosin, benazepril. Either increases effects of the other by pharmacodynamic synergism. Minor/Significance Unknown. May increase risk of hypotension.
- captopril
tamsulosin, captopril. Either increases effects of the other by pharmacodynamic synergism. Minor/Significance Unknown. May increase risk of hypotension.
- cyclophosphamide
cyclophosphamide will increase the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- drospirenone
drospirenone will increase the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
Adverse Effects
>10%
Headache (19-21%)
Orthostatic hypotension (6-19%)
Rhinitis (13-18%)
Abnormal ejaculation (8-18%)
Dizziness (15-17%)
Arthralgia (11%)
Infection (9-11%)
1-10%
Asthenia (8%)
Back pain (7-8%)
Skin rash (7%)
Pharyngitis (5-6%)
Diarrhea (4-6%)
Myalgia (5%)
Chest pain (4%)
Cough (3-4%)
Somnolence (3-4%)
Nausea (2-4%)
Sinusitis (2-4%)
Abdominal discomfort (2-3%)
Bitter taste (2-3%)
Decreased libido (1-2%)
Insomnia (1-2%)
Postmarketing Reports
Priapism (rare)
Signs and symptoms of orthostasis, including syncope
Infrequent reports of dyspnea, palpitations, hypotension, atrial fibrillation, arrhythmia, and tachycardia
Visual impairment
During cataract and glaucoma surgery, a variant of small pupil syndrome known as Intraoperative Floppy Iris Syndrome (IFIS) has been reported in association with alpha1 blocker therapy
Skin desquamation including reports of Stevens-Johnson syndrome, erythema multiforme, and dermatitis exfoliative
Constipation, vomiting, and epistaxis
Allergic-type reactions (eg, skin rash, urticaria, pruritus, angioedema, respiratory symptoms) have been reported with positive rechallenge
Dry mouth
Warnings
Contraindications
Hypersensitivity
Cautions
Use with caution in coronary artery disease, liver disease, general anesthesia
Orthostatic hypotension may occur
Priapism rarely reported
Prostatic cancer should be ruled out before therapy is initiated
May cause syncope (first-dose effect)
Discontinue if angina symptoms occur or worsen
Intraoperative floppy iris syndrome has been reported in patients receiving alpha1 blockers at time of cataract surgery; association is unclear
Patients with sulfa allergy have rarely developed allergic reaction; avoid use if previous sulfa allergy reactions have been life-threatening
Not for use as antihypertensive drug
May exacerbate heart failure
Pregnancy & Lactation
Pregnancy
No data are available on use in pregnant women
No adverse developmental effects observed in animal studies administering tamsulosin to rats or rabbits during organogenesis
Infertility
- Males: Abnormal ejaculation including ejaculation failure, ejaculation disorder, retrograde ejaculation, and ejaculation decrease has been associated with therapy; studies in rats revealed significantly reduced fertility in males considered to be due to impairment of ejaculation, which was reversible
- Females: Drug is not indicated for use in women; female fertility in rats was significantly reduced, considered to be due to impairment of fertilization
Lactation
There are no data on presence of drug in human milk, effects on breastfed infant, or on milk production
No data are available; owing to potential of tamsulosin to cause hypotension, breastfeeding is not recommended if taking tamsulosin
Pregnancy Categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk. C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done. D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk. X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist. NA: Information not available.Pharmacology
Mechanism of Action
Blocks alpha1a adrenergic receptor in smooth muscle of prostate, decreasing bladder neck and urethral resistance
Absorption
Bioavailability: Fasting, 30%
Onset: 4-8 hr
Peak plasma time: With food, 6-7 hr; fasting, 4-5 hr
Distribution
Protein bound: 90%
Vd: 0.2 L/kg or 16 L
Metabolism
Metabolized in liver
Metabolites: Glucuronide and sulfate conjugates (inactive)
Elimination
Half-life: 14-15 hr
Excretion: Urine (76%), feces (21%)
Administration
Oral Administration
Administer 30 minutes after same meal each day
Do not crush, chew, or open capsules
Images
| BRAND | FORM. | UNIT PRICE | PILL IMAGE |
|---|---|---|---|
| Flomax oral - | 0.4 mg capsule |  |
Copyright © 2010 First DataBank, Inc.
Formulary
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