Density functional theory calculations were performed to inspect the potential application of pristine AlN nanotube (AlNNT) as well as Pd-decorated AlNNT (Pd@AlNNT) in recognition of gabapentin (GB) drug. The sensing response of AlNNT to the GB drug is very small (similar to 5.2 at 298 K) attributed to the small adsorption energy (AE) of -0.16 eV. Molecular orbital energy decomposition method (EDA) showed that the contributions of electrostatic attraction, Pauli repulsion, orbital relations, and dispersion forces in the AE are about -0.21, 0.19, -0.11, and -0.09 eV, respectively. A Pd atom preferentially adsorbed over an Al-N bond of the AlNNT, releasing the energy of 2.93 eV. We found that the GB strongly adsorbed on the Pd@AlNNT with AE of -1.29 eV and the sensing response increased to 524.6 by the Pd decoration. Based on the results, the main stabilization contribution to the AE of GB on the Pd@AlNNT comes from the electrostatic attraction based on the EDA analysis. The recovery time was achieved to be 1.8 s for the GB desorption from the Pd@AlNNT surface. Finally, we concluded that the Pd@AlNNT can transform the presence of GB molecules into electrical signal, and it may potentially be applied as an electronic sensor for GB drug detection.