Calcium Channel Blockers include -

Bepridil, Diltiazem, Felodipine, Isradipine, Nicardipine, Nifedipine,
 Nimodipine, Verapramil, Amlodipine, Nisodipine, Clevidipine, Lercandipine
 Refer verapramil-

Interacting drugs -summary-         
          
+  Felodipine -

Barbiturates
Felodipine bioavailabilty decreased

Erythromycin
 pharmacological & toxic eff of Felodipine  increased

Cimetidine
  bioavailabilty  of Cimetidine increased

Ranitidine
bioavailablity  of Ranitidine increased

Hydantoin
 serum Felodipine levels decreased

Carbamazepine
increased carbamazepine serum levels with possible toxicity may occur. Plasma levels of felodipine may be decreased    

Betablockers
coadministration may result in increased adverse effects due to depressant effects on myocardial contractility or AV conduction

Barbiturate
Felodipine plasma leveld and bioavailabilty may be reduced

Increases plasma digoxin concentration by approx 40%.
Concomittant admin of substances interfering with cytochrome P450 enzymes may affect plasma  concentration of felodipine.
Plasma levels enhanced by enzyme inhibitors(eg Cimetidine).
Plasma levels reduced by enzyme  inducers(eg Phenytoin, carbamazepine, barbiturates).
Concomittant admin of beta-blkrs reduces side effects.

FELODIPINE-
----------------
CNS -           Headache  18% Dizziness/lightheadedness  6 %, Asthenia 5%,

                      Parathesia 3%,
                      Nervousness,Psychiatric disturbances,Depression, Amnesia,Paranoia, Psychosis,
                      Hallucinations , Somnolence,  Insomina , Anxiety < 2%

GASTROINTESTINAL-  Abdominal discomfort/cramps/dyspepsia    2 % Nausea 2%, Diarrhea
                                        Constipation 2%, Vomting,dry mouth/thirst, Flatulence  <2 %

CARDIOVASCULAR-   Periph.edema  22%, Palpitation 2%,Hypotension, Syncope,
                                      AV block  1,2,3 degree ,Myocardial infarction,Arrhythmias
                                      unspecified,  Angina, Tachycardia  < 2 %
 
DERMATOLOGICAL-   Dermatitis/rash 2 %, Pruritis/urticaria  < 2 %
        

HAEMATOLOGICAL-   Anemia   < 2%

OTHER-                        Flushing  6% ,  Cough 3% Muscle cramps/ pain/inflammation,
                                       joint stiffness, arthiritis < 2%,
                                      Nasal or chest cong/sinusitis/ rhinitis , Mituration disorder,
                                      polyuria/nocturia/dysuria/frequency,  Sexual difficulties,
                                      Shortness of breath/dyspepsis, wheezing , epistatixis,  < 2%

Hypersensitivity.Pregnancy including early stages.

Special precautions:

May cause rare hypotension with tachycardia resulting in myocardail ischemia in susceptible patients,severe liver disease.

Approved by  FDA in  May 1991

Hypertension

Dosage:

Individualise dose. Initial dose - 5mg once daily. Usual dose varies between 5 to 10mg. Maximum dose is 20mg once daily.

 Refer verapramil-

Refer - Verapramil- Calcium channel blockers

Refer- Verapramil- Calcium channel blockers

Refer - Verapramil- Calcium channel blockers