The FUNDC2P4 gene is a pseudogene associated with the FUNDC2 gene, which has implications in cellular processes such as mitophagy and regulation of mitochondrial dynamics. Below are the details addressing your questions:

### 1. Associated Genes
While the specific associations with other genes for FUNDC2P4 are not extensively documented, the following genes may be relevant based on their connection to FUNDC2, the reference gene:
- **FUNDC2**: As a closely related gene, it has been implicated in the regulation of mitochondrial dynamics, particularly mitophagy.
- **ATG7**: Involved in autophagy, a process inherently connected to the activity of FUNDC2.
- **PINK1**: It plays a crucial role in mitochondrial quality control and is often discussed in the context of FUNDC2 and mitophagy.
- **PRKN (Parkin)**: Like PINK1, it is involved in the selective autophagy of dysfunctional mitochondria.

### 2. Aging and Age-Related Diseases
Although specific information about FUNDC2P4 and its direct role in aging or age-related diseases is limited due to its status as a pseudogene, the following details can be inferred through its association with FUNDC2:
- **Mitophagy and Aging**: FUNDC2 is involved in the selective degradation of damaged mitochondria, a process that tends to decline with age, potentially contributing to age-related cellular dysfunction.
- **Neurodegenerative Diseases**: As FUNDC2 functions in mitochondrial health, dysregulations in its pathway can contribute to conditions like Alzheimer's disease and Parkinson's disease, emphasizing mitochondrial integrity's importance in aging.

### 3. Drug Interactions
As of the latest update, there are no specific drugs or drug classes directly associated with the FUNDC2P4 gene due to its classification as a pseudogene. However, because FUNDC2 interacts with cellular pathways affected by various therapeutics aimed at mitochondrial and autophagy processes, research into drugs targeting mitophagy (e.g., rapamycin and its analogs) may have indirect implications.

### 4. Pathways and Biological Processes
- **Cellular Response to Hypoxia**: FUNDC2 is activated during hypoxic stress, and as such, FUNDC2P4 may also be linked to responses involving oxygen deprivation.
- **Mitochondrial Quality Control**: Both FUNDC2 and its associated functions suggest relevance in monitoring and maintaining mitochondrial health.
- **Autophagy**: Pseudogenes like FUNDC2P4 can affect gene expression of their respective counterparts (FUNDC2), potentially modulating autophagy processes.
- **Stress Response**: Handling cellular stress through mitochondrial dynamics and associated cellular mechanisms may be another area of biological relevance.

In summary, while the scientific literature specifically focusing on FUNDC2P4 is limited due to its classification as a pseudogene, it is conceptually tied to important biological pathways related to mitochondrial health, autophagy, and potentially age-related cellular processes through its relationship with FUNDC2. Further research is warranted to elucidate its precise roles and mechanisms in these areas.