Tadalafil is a phosphodiesterase 5 (PDE5) inhibitor indicated for the treatment of- Erectile
dysfunction  (ED),  The  signs  and  symptoms  of  benign  prostatic  hyperplasia  (BPH),  ED  and  the  signs  and symptoms of BPH (ED/BPH) & Pulmonary Hypertension

Tiagra  for  Use  as  Needed  for  Erectile  Dysfunction:
  The  recommended   starting  dose  of  Tadalafil  for  use  as  needed  in  most  patients  is  10  mg,  taken  prior  to  anticipated  sexual  activity.  The  dose  may  be  increased  to  20  mg  or  decreased  to  5  mg,  based  on  individual efficacy  and  tolerability.  The  maximum  recommended  dosing  frequency  is  once  per  day  in  most patients. Tadalafil for use as needed was shown to improve erectile function compared to placebo up  to  36  hours  following  dosing.  Therefore,  when  advising  patients  on  optimal  use  of  Tadalafil,  this  should be taken into consideration.

Tadalafil  should  not  be  used  together  with  nitrate  medication,  such  as  nitroglycerin  (Nitro  Dur,  Nitrolingual,  Nitrostat,  Transderm  Nitro,  and  others),  isosorbide  dinitrate  (Dilatrate,  Isordil,Isochron), isosorbide mononitrate (Imdur, ISMO, Monoket), or recreational drugs such as amyl nitrate or  nitrite  ("poppers").  Taking  Tadalafil  with  a  nitrate  medicine  for  chest  pain  or  heart  problems  can  
cause  a  sudden  and  serious  decrease  in  blood  pressure.  severe  impairment  of  pulmonary  or  renal  function;  moderate  impairment  of  hepatic  function;  and  toxic  psychosis.  Use  not  recommended  in  patients  with  a  recent  MI  (within  90  days)  or  stroke  (within  6  months);  uncontrolled  arrhythmias,  hypotension  (<90/50  mm  Hg  systolic/diastolic  BP)  or  uncontrolled  hypertension  (170/110  mm  Hg  systolic/diastolic  BP);  heart  failure  (>NYHA  class  II)  in  the  previous  6  months;  or  those  with  unstable  angina  or  angina  occurring  during  sexual  intercourse.  Possible  hypotension,  particularly  in  patients  with  left-ventricular  outflow  obstruction  (e.g.,  aortic  stenosis,  idiopathic  hypertrophic  subaortic   stenosis) and in patients with severely impaired autonomic control of blood pressure.

Pediatric Use: Safety and efficacy not established in patients <18 years of age.
Geriatric  Use:   Safety  and  efficacy  in  those  >  65  years  of  age  is  similar  to  that  in  younger  men.   Possibility exists of greater sensitivity to the drug in some geriatric individuals.

Use  in  Patients  with  Hepatic  Impairment:   Use  not  recommended  in  patients  with  severe  hepatic  impairment.
Use  in  Patients  with  Renal  Impairment:   Clearance  decreased  in  patients  with  mild  (Clcr  51-80  ml/minute) to severe renal insufficiency (end-stage renal disease on hemodialysis), and may result in increased adverse effects (e.g., back pain). No dosage adjustments are necessary in those with mild renal  impairment.  Creatinine  clearance  less  than  30  mL/min  or  on  hemodialysis:    Tadalafil  for  once  daily use is not recommended

Administration  of  Tadalafil  to  patients  who  are  using  any  form  of  organic  nitrate,  
either  regularly  and/or  intermittently,  is  contraindicated.  In  clinical  pharmacology  studies,  Tadalafil  was shown to potentiate the hypotensive effect of nitrates

Tadalafil  can  potentiate  the  hypotensive  effects  of  nitrates,  alpha  blockers, antihypertensives  or  alcohol.  CYP3A4  inhibitors  (e.g.  ketoconazole,  ritonavir)  increase  Tadalafil  exposure.  For  concomitant  use  with  potent  CYP3A4  inhibitors,  dose  adjustment  may  be  needed.  CYP3A4 inducers (e.g. rifampin) decrease Tadalafil exposure

Single doses up to 500 mg have been given to healthy subjects, and multiple daily doses up to 100 mg have been given to patients. Adverse events were similar to those seen at lower doses. In cases of overdose, standard supportive measures should be adopted as required.Hemodialysis contributes negligibly to tadalafil elimination