Judge Geraldine Fiel-Macaraeg of the Marikina Regional Trial Court Branch 192 also ordered accused Adu Satirada to pay the government a fine of P500,000.
Macaraeg gave weight to the positive identification made by a police raiding team led by Superintendent Romeo Abaring over Satiradas alibi.
In her defense, Satirada said she was cooking dinner when unidentified men barged into her house looking for a drug suspect.
Failing to find the suspect, the policemen took her into custody instead, the accused claimed.
But in her 12-page decision, Macaraeg found Satiradas theory that police were supposedly after a male person "incredible and unbelievable."
"I find it unbelievable that police would pick a woman to take place of their supposed target," the judge said.
Court records showed that Abaring, head of the anti-drug unit of the Marikina police, ordered a buy-bust operation against Satirada on March 8, 2005 following reports that she was behind the proliferation of shabu in Barangay Concepcion I.
PO3 Ramuel Soriano, who acted as a buyer, managed to arrange the purchase of P100 worth of shabu from Satirada. The deal was to be made in front of her house on Singkamas street, Sitio Tumana in Barangay Concepcion I at about 7 p.m.
After the suspect handed him a sachet of shabu in exchange for P100, Soriano signaled his companions for a positive test buy.
Before the policemen could collar Satirada, she ran inside her house, where she was later cornered.
The accused had insisted she was unlawfully arrested.
Satirada said she would appeal the case.